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Updated CDC Zika Laboratory Testing Guidance


Welcome and thank
you for standing by. At this time all participants
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turn the conference over to William Koehne. Thank you, you may begin. Thank you Jennifer. Good afternoon. I’m William Koehne and I’m
representing the Clinician Outreach and Communication
Activity, COCA with the Emergency
Risk Communications Branch at the Centers for Disease
Control and Prevention. I’m delighted to welcome you to today’s COCA call Updated
CDC Laboratory Testing Guidance. You may participate in
today’s presentation by audio only via webinar or
you may download the slides if you are unable to
access the webinar. The PowerPoint slide set and
the webinar link can be found on our COCA Web page at
emergency.cdc.gov/coca. Free continuing education is
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continuing education will be provided at the end of the call. CDC, our planners, presenters
and their spouses/partners wish to disclose that they
have no financial interest or other relationships
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suppliers of commercial services or commercial supporters. Planners have reviewed
the content to ensure there is no bias. This presentation will
not include any discussion of unlabeled use of
products or products under investigational use. At the end of the presentation
you’ll have the opportunity to ask the presenters. On the phone dialing Star
1 will put you in the queue for questions and you
may submit questions through the Webinar system at
any time during the presentation by selecting the Q&A tab at
the top of the webinar screen and typing in your question. Questions are limited
to clinicians who would like information about Zika
and laboratory testing. For those with media questions
please contact CDC media relations at 404-639-3286 or
send an email to [email protected] If you are a patient
please refer your questions to your healthcare provider. At the conclusion of today’s
session the participants will be able to: describe all available
food and drug administrative – administration emergency
use authorizations for Zika virus assays; discuss
Zika virus testing methods including molecular and antibody
detection; explain the role of public health
laboratories, clinicians, and health departments
and Zika virus testing; and identify Zika virus
laboratory testing algorithms and resources. Today’s first presenter is
Dr. Christy Ottendorfer. Dr. Ottendorfer is currently
serving as a team lead of the Zika Lab Team Task Force at CDC’s Emergency
Operations Center. As a Virologist she’s
conducted doctoral and postdoctoral research on arboviruses including
flaviviruses. Prior to CDC, Dr. Ottendorfer’s
work experience included laboratory positions at the state public
health reference laboratory at the Florida Department
of Health for clinical laboratory
testing and diagnosis of arboviral diseases. Our second presenter is
Dr. Matthew J. Binnicker with the American
Society for Microbiology. Dr. Binnicker completed
a fellowship at – in clinical microbiology at Mayo
Clinic in Rochester Minnesota. He is currently the
Director of Clinical Virology and an Associate Professor
of Laboratory Medicine and Pathology at Mayo Clinic. Our third presenter is Dr.
Grace Kubin with the Association of Public Health Laboratories. Dr. Kubin has been the Director for the Texas State Public
Health Laboratory since 2011. She has been involved with
multiple disease outbreaks which required rapid
increase in capacity such as the 2001 H1N1 pandemic, West Nile in 2012
and Ebola in 2014. At this time please
welcome Dr. Ottendorfer. Good afternoon everyone. My name is Christy
Ottendorfer with the Centers for Disease Control
and Prevention. And today’s presentation I’ll
be covering the new guidance for U.S laboratories testing
for Zika virus infection. As CDC learns more about Zika
virus CDC incorporates new information into its laboratory
guidance for Zika virus so that we can refine
and improve these assays. During this call I have included
some questions here for you to consider as a part
of the new algorithms that have been developed. Approximately two weeks ago CDC
issued an update to its guidance for US laboratories
testing for Zika virus. This guidance expands
the test parameters for CDC’s approved Trioplex
RT-PCR assay as well as acknowledging other
available commercial tests. In addition the guidance
document provides additional clarification for
symptomatic patients and asymptomatic pregnant women
with epidemiological criteria that should be tested, plus the
appropriate testing algorithms. The full algorithms are located
on the website noted here and will be covered
in more detail by another presenter today. As you may have experienced,
laboratory diagnosis of Zika virus is complicated. There is often cross-reactivity with other circulating
flaviviruses or prior yellow fever
vaccination history in patients. This figure provides
some background on why different tests
and specimens are needed. Following exposure Zika virus
RNA is the first detectable analyte in the blood. That’s shown in the first curve. Zika virus RT-PCR
should be performed for specimens collected within
14 days after onset of symptoms. Urine and amniotic fluid
can also be collected for this type of molecular test. As viremia declines the
second detectable analyte, anti-Zika IgM antibodies,
that are shown in the second curve, will rise. Serology assays are used to
detect Zika virus specific IgM and neutralizing antibodies which typically develop
towards the end of the first week of illness. Of note IgM antibody levels
also decline over time. As a result anti-Zika IgM
antibodies can be detected up to 12 weeks after infection. Since these analytes rise and
fall over time it’s important to collect a paired serum
to assist in diagnosis as antibody levels
may remain elevated for a longer time period
than the viral RNA. Finally as a reminder
testing should be limited to specimens collected from individuals
meeting CDC’s clinical and epidemiological criteria. There are three assays
that are commonly used to detect Zika virus,
nucleic acid tests, which are also commonly
called RT-PCR assays, are used to detect viral RNA. In addition there are two
types of serological assays, the IgM ELISA and the plaque
reduction neutralization test or PRNT. The Zika MAC-ELISA is used
for presumptive detection of the Zika IgM antibodies and
specimens that are positive on Zika MAC-ELISA are currently
further analyzed using a plaque reduction neutralization test; however PRNT confirmation is not
currently routinely recommended in Puerto Rico. And this is one of the updates
to the laboratory guidance that was recently issued. The reason for this is
there is a high prevalence of dengue virus and
cross-reactivity in these tests in that area. CDC developed the first two
diagnostic assays for Zika virus that FDA issued an
Emergency Use Authorization. The MAC-ELISA is used
for presumptive detection of anti-Zika IgM antibodies, whereas CDC’s Trioplex
RT-PCR can detect Zika, dengue and chikungunya viral
RNA, which can distinguish from other viruses with similar
clinical signs of Zika virus. These Trioplex test results can
help inform important clinical and public health decisions
as well as improve efficiency and throughput of
laboratory testing. CDC’s Zika diagnostic assays are
distributed in the United States in the Laboratory
Response Network, and have also been distributed
internationally including over 1000 Trioplex RT-PCR
kits to 115 countries. The low level of
viremia observed in some Zika virus cases poses a
challenge for molecular testing. As a result, CDC continues to
refine and improve its assays. Recently the FDA approved
the addition of whole blood and analysis of larger
sample volumes for CDC’s Trioplex assay. These updates were demonstrated
to increase the sensitivity of the Trioplex assay and both
methods may improve detection of low levels of viral RNA. Further, new laboratory
instruments were approved that are commonly available
in diagnostic laboratories. This is an overview of
other commercial assays that have been developed for
Zika virus diagnostic testing. There are ten commercial
diagnostic manufacturers that have received an FDA EUA for molecular test
for Zika viral RNA. Recently all manufacturers with EUA molecular
tests were requested to reassess individual test
sensitivity using an FDA recommended reference panel. The FDA reference
panel contains RNA from two current
Zika virus strains and three controls
for blind testing. Test performance results of
these assays will be published so that test performance can be
compared among EUA manufacturers by laboratories nationwide. Besides the CDC Zika MAC-ELISA
one commercial diagnostic manufacturer has received
an EUA for serological test. Similar to the FDA reference
panel mentioned above, three independent laboratories
are also conducting performance evaluation of the
available serological assays. These results will help
inform future laboratory testing decisions. Three commercial
laboratories have been licensed and are using CDC’s
Zika MAC-ELISA. This is an overview of all of
the nucleic acid-based EUAs that are approved for
Zika virus testing. Note whole blood is approved
for CDC Trioplex assay only. Please check with
your laboratory prior to specimen collection as each
EUA has specific requirements and which assays are
available at that laboratory. Specific information on
each FDA EUA is available at the website noted here and
refer to the labeling section for further instructions. This is an overview of the available IgM
antibody test for Zika. Further CDC is meeting
with states with high risk of local transmission. At this time the state of Texas
has identified a potential case of local Zika virus transmission and CDC is supporting
their investigation. Fortunately we have Dr. Kubin on
the line today and she will be, I’m sure, have a lot of
lessons or a lot of discussion of this topic and things that
they’re learning at this time. In addition CDC works to ensure
there is adequate laboratory capacity for potential testing
demand and providing reagents to support the CDC developed
assays for Zika virus. In closing, CDC recently issued
updated laboratory guidance as we learn more about Zika
virus infection and detection. To improve sensitivity of the
CDC Trioplex assay whole blood and analysis of larger sample
volumes were added to the EUA. Serum must also be collected
for serological testing. FDA has approved several EUAs for Zika virus clinical
diagnostic testing as well so not only CDC developed
assays. CDC will continue to
monitor Zika virus disease and incorporate what is learned into its recommendations
and guidance. Thank you for your attention. All right, so this
is Matt Binnicker. I’m the Director of Clinical
Virology at Mayo Clinic and I want to thank everyone
who’s calling in today for this update on
Zika virus testing. I also want to thank APHL, ASM,
who I’m representing today, and the CDC for coordinating
this important webinar and for inviting
me to participate. So the goal for my portion
of the presentation will be to provide you with an update
on the assays that are available to clinical laboratories for
the diagnosis of Zika virus. And then we’re going to highlight how we
can use these tests. And we’re going to do
that by reviewing a series of case vignettes. I think one of the things
that we’ve come to recognize and appreciate since
the beginning of the Zika virus outbreak
is that our success at controlling this virus is
going to require a team effort. It’s going to depend
on careful coordination and cooperation among healthcare
providers, public health, but also clinical laboratories. And I can’t stress enough
that involvement of both local and private diagnostic
laboratories will be essential in optimizing our ability to control this emerging
viral threat and diagnose and manage our patients. And I think this is because the
local laboratories are going to be closest to the patient,
and can provide the most rapid and actionable results. And in addition, clinical
labs must be involved and play an integral role so
that we can reduce the burden of testing that’s placed
on our public health labs, such as the CDC, during
these outbreak settings. Currently, as was reviewed
during the first portion of the presentation,
diagnostic assays for Zika, whether they be molecular
or serologic, require emergency use
authorization from the Food and Drug Administration prior
to being used routinely. The CDC assays were the first to receive emergency
use authorization, and as was discussed,
include the Trioplex PCR and the MAC-ELISA serology test. Trioplex detects Zika,
dengue, and chikungunya viruses from a variety of
different sample types. And according to the
latest testing guidelines that were released recently, serum remains the preferred
sample type but now whole blood and additional sample
types can be submitted. But if they are [submitted],
they should be accompanied by a paired serum sample. There have been some recent
studies that have been published and shown that Zika virus
may be shed in sample types such as urine and whole blood
for longer periods of time. So those samples may be a
good option if it’s been more than a week or 14 days since
the patient had their onset of symptoms. Importantly, the Trioplex PCR
assay is currently available only at the CDC and in
select CDC designated public health labs. The MAC-ELISA assay
is a serologic test, that detects IgM class
antibodies from serum samples and at this time it is available
only at the CDC but also at CDC designated
public health labs, and also some designated
reference laboratories. Fortunately, as was reviewed
earlier, there are now a number of commercial assays that received emergency use
authorization and are available for detection of
Zika nucleic acid or antibodies directed
against the virus. The table on this slide
is similar to the one that was shown earlier. It summarizes some of
these commercial assays that have received EUA. The second column of the
table summarizes the method that is used, for
example, real-time RT-PCR or transcription mediated
amplification, or in the case of the commercial assay that is
approved for serologic testing, it utilizes an IgM
Capture ELISA technique. The third column also
shows the sample types that have received EUA for
each of the respective assays. I should emphasize though
that this is not going to be an all-inclusive list and that additional assays
will likely become available in the coming months from
various commercial companies. So now that we have a better
appreciation for the assays that are available
to both public health and clinical laboratories
for the diagnosis of Zika virus infection, I wanted to spend some time
discussing how these tests should be used in
the clinical setting. And we’re going to do that
by reviewing four short clinical cases. So in the first case we
have a 27-year-old female who has recently returned
from vacation in Jamaica. And one week after
arriving back home, the patient takes a pregnancy
test, which is positive. However, the patient was
well throughout the course of her trip and has not had any
symptoms following her return so in her conversations with
her primary care provider and her obstetrician,
the question comes up, “Is Zika testing recommended
in this patient, and if so, what type of testing
should be performed?” Due to this patient
being pregnant and recently visiting an area where Zika virus
transmission is occurring, diagnostic testing would be
recommended in this case. A key factor in determining
which type of testing should be
performed is the amount of time that’s passed between
the patient’s return from travel or their last possible exposure, and when they present
for evaluation. So if it’s been greater than 14
days since the patient returned from travel or had their
last potential exposure then serologic testing is
recommended, and that’s shown in the grayed out portion
on the right-hand side of the algorithm on this slide. However, if it’s been less than
14 days, as is the situation in this case, then
it’s recommended to test a serum sample by
an EUA approved PCR method for Zika virus. Urine and whole blood
now may also be tested, but if they’re submitted,
they should be accompanied by a paired serum sample. So a positive PCR result in any of these specimen types
would be diagnostic for Zika virus infection. And that’s showed again grayed
out on the left-hand side. But our patient, however,
tested negative by PCR. Now you might think that
with a negative PCR result, we’d be done with
testing in this case. But in pregnant females
who test negative by PCR and are presenting
less than 14 days after their last potential
exposure, it’s recommended to collect a serum
sample between that two and 12-week timeframe after
their return from travel and that serum sample
would then be tested for IgM class antibodies. And that’s because the period of
positivity by PCR is very brief, as was highlighted
with the figure earlier on during the presentation. In our second case we have
a 45-year-old gentleman from Honduras. And he visits his
family in Texas. He indicates that he was well
during the first seven days of his visit but has experienced
an intermittent low grade fever, a rash, and mild joint pain over
much of the past 2-1/2 weeks. So again the question comes up, “Is Zika testing
indicated in this patient?” So as we learned in the first
case, one of the first pieces of information that we need to drive appropriate testing
is determining the amount of time that’s passed between
exposure or symptom onset. So in this case it’s
been over two weeks since the patient
developed symptoms, so the recommended
approach would be to test a serum sample
by Zika IgM serology. In addition, serologic
testing for chikungunya and dengue virus would
also be indicated since they can be
circulating in that area and cause a very similar
clinical presentation. Our patient tested positive
for IgM class antibodies to Zika virus and results for dengue were interpreted
as equivocal. In this situation, the serum
sample should be tested by plaque reduction
neutralization at CDC or a designated lab prior
to confirming the diagnosis as Zika virus infection. In our third case, we
have a 57-year-old female who lives in Des Moines, Iowa. And she recently
visited Haiti as part of a church mission trip. Two days after returning home, the patient contacts her primary
care provider, and like most of us has seen a lot of
information of Zika on the news, and so this patient is worried
and requests testing for Zika. When asked whether the
patient has been ill, the patient responds that
she was well during her trip and remains asymptomatic but
is worried about an exposure. So in this case, is
testing recommended? The current guidelines state that diagnostic testing
is not recommended in asymptomatic non-pregnant
individuals such as the patient
in this case. One caveat that we need to
consider is blood donors and potentially organ
and/or tissue donors. On August 26 of this
year, the US Food and Drug Administration
recommended that all blood donated in
the United States be screened for Zika virus using
a molecular test. Currently there are several
screening assays available, which use nucleic acid
amplification technology. We definitely need more data
to guide testing in this area, especially in regards to
screening organ donors that have visited or reside
in the Zika endemic region. And our final case is
of a 29-year-old female who has laboratory-confirmed
Zika virus infection during the second trimester of
her first pregnancy. And following delivery of
her child, a clinical exam of the infant is performed
which reveals no evidence of any physical abnormalities. So in this situation where we
have an infant with no evidence of disease but that
infant is born to a mother who had lab-confirmed Zika virus
infection during pregnancy, is specific testing for Zika
virus in the infant recommended? So the answer in
this case is, yes, lab testing would be recommended
and it’s recommended for infants who are born to mothers with
lab evidence of Zika infection. But in addition, testing is
also indicated for infants with findings suggestive of
congenital Zika who are born to mothers with an
epidemiologic link. For example, did the
mother travel to or live in an endemic region for
Zika virus during pregnancy? So if those characteristics
or features are met, initial testing of the infant
should include Zika PCR of serum and urine, and as well, serology
testing should be performed on the serum sample collected from the infant using an assay
detecting IgM class antibodies to Zika virus. The table on this slide
provides a summary of how lab results should
be used and interpreted when evaluating a patient for possible congenital
Zika virus infection. So in the very first
scenario, we have an infant with a positive PCR
result on any sample type. And then regardless of
the serology findings, if the PCR result is positive, this patient would be
interpreted as a case of confirmed congenital
Zika virus infection. For those infants that test
negative by PCR but are positive for IgM class antibodies
by serology, they would be considered to have
probable congenital infection. Finally, newborns testing
negative by both PCR and IgM serology, as is going
to be the case in the majority of the patients that we see, these individuals will be
interpreted as negative for congenital Zika
virus infection. So to summarize this
portion of the presentation, Zika virus poses a significant
challenge to public health and clinical diagnostic labs. I’d reemphasize that a coordinated effort
involving healthcare providers, clinical labs and public health
will continue to be needed to identify cases and
control the outbreak. And finally, one thing that is
certain is that this is going to continue to be
an evolving process. We continue to learn more about
the virus with each passing day and new data are going to
continue to become available that will guide our
diagnostic algorithms. So maintaining flexibility and
focusing on good communication between the provider at the
bedside and the clinical lab and then ultimately
with our colleagues in public health will be keys
to success in the future. So with that I’m going to pass
the baton on to my colleague. Dr. Grace Kubin. who will provide you with
some guidance and information from the perspective of
the public health lab. Hi. Good afternoon everyone or good morning wherever
you may be located. Thanks very much to my
colleagues on this webinar for giving such an
excellent overview and discussion about
Zika testing. I also would like to thank
ASM and of course APHL who I’m representing on the
call today for the opportunity to speak about this topic. As Dr. Ottendorfer mentioned
earlier this week we announced in Texas that we are
investigating a Zika case that was probably caused
by local transmission. So needless to say my colleagues
here at the health department and everybody at the lab have
been quite busy this week as well as a lot
of our individuals out in the local health
departments spent a good deal of their Thanksgiving
holiday dealing with this too. So I want to thank our
colleagues in Florida as well as Dr. Ottendorfer for all her
help and assistance and insights as we’re trying to work through
all the issues that we’ve seen with this most recent case. So I just kind of wanted to
talk a little bit about some of the parallels that we saw
with Zika and that we also kind of saw in the Ebola response. Ebola and Zika viruses
were similar in that not much is
known about them. Zika virus was first
identified in the late 1940s but was not really seen in
humans until the early 1950s. As you know, Ebola was
not well-characterized. I think it was seen quite
a bit earlier but still, not much was really
known about it. And of course the first
documented large-scale outbreak for Zika did not occur until
2007 which was on Yap Island. I’m sure many of you who
are having to be involved in Zika response probably
have heard quite a bit about that outbreak. And we also really
didn’t know much about how the virus
performs in the body and other characteristics such
as how long it might persist in the body and in what type
of fluid, cells, or tissues. There was also a lot of
confusion regarding testing and shipment of specimens. So initially, most commercial and private labs did not perform
either the Ebola or Zika tests and providers were unfamiliar
with how to get specimens to the public health
laboratories who did do that testing. With a typical infectious
disease I’m sure most of you are aware that usually
the primary care providers are the ones who are most involved. But with both of these diseases
we saw many different healthcare providers involved
in the response. First responders, emergency
department personnel, and individuals that were
working with patients in isolation for
the Ebola response. And for Zika OB/GYNs, neonatal
personnel, and to steal a term from my Florida colleagues
the baby catchers, so those individuals who really
are involved with pregnancy and the – what happens
after they, you know, provide, give birth. So let’s talk a little bit
about the actual testing. So you heard already on this
webinar that there are many – there are several
different types of tests that have been approved
by the FDA for EUA. Public health laboratories
have a lot of different types
of test offerings. So some labs still perform
what we call the PCR Singleplex assay. Of course many of the
labs, public health labs, perform the Trioplex assay. And of course as Dr. Binnicker
mentioned that’s only allowed for laboratories who are part of the Laboratory Response
Network and approved by CDC. Some of the public health labs or commercial labs perform
both RT-PCR and serology, of which for the serology some of the labs might
perform Zika only IgM and some also may perform
chikungunya as well dengue IgM. And of course some labs
will perform all three PCR, serology, and PRNT. Of course needless to say
these testing menus can be quite variable. That’s why I really encourage
if you’re looking for testing to check the websites for each of the public health
laboratories whether it’s at the city, county,
or state level and also for the commercial
laboratories and private labs. And also you might want
to familiarize yourself with the tests that
are EUA approved. As mentioned detailed
information about those assays can be found on the FDA medical
device EUA website. Okay so I’m probably going
to sound a little bit like a broken record but individual websites are an
excellent source for helping to know how much specimen to
collect, how it should be stored if not sent right away,
and under what type of conditions it should be
sent whether it be either cold or frozen. You know, really the type of
testing, what type of specimens that you are collecting and how
you should ship them are really critical to ensuring that
we’re able to perform the tests that are needed for the patient. In addition our laboratory and many other labs are
collecting additional information beyond the symptoms
and the symptom onset date. This includes pregnancy status
and at what point the patient is in during her pregnancy
when she is getting testing or maybe has been exposed,
the patient’s travel history, f course this is not necessarily
an unfamiliar territory as we had to do this with Ebola, ut then we’re also looking
to have the travel history of any sexual partners. This information really is
being used to determine at least in our health department as to what is the most
appropriate testing for the patient. Our epidemiologists spend a
large amount of time, you know, having familiarized themselves
with the algorithms and all of this extra information
that we’re collecting to really ensure that we in
the lab are doing the tests that are most appropriate
for that patient. In addition this information
is also required if we end up having to submit specimens
to CDC for additional testing. So as mentioned previously
serum is of course the preferred
specimen type for RT-PCR. But depending on which type
of test is being performed in the lab that you
might be using or working with either whole blood, urine,
or CSF could be submitted. But I will say that all
three of these types of specimens will
require a paired serum. So, you know, if you’re going
to be sending us the urine, whole blood or CSF please also
send a paired serum with that. For this test, for RT-PCR a
positive result is considered conclusive so really no
additional testing is required. Under normal circumstances
and what I kind of mean by that is not in the middle of a local transmission
investigation and of course taking into
account the lab’s capacity, PCR results could possibly be
available two to three days from the time the specimen
arrives in the laboratory. And of course this is
a conservative estimate and it could be really a shorter or longer time really depending
upon the lab’s capacity and availability for testing. So for serology specifically
the MAC-ELISA serum of course is the
only specimen type. The MAC-ELISA really
is a multi-day test and results may be
available three to four days after arrival in the lab. Again that’s kind of a
conservative estimate based on capacity of the lab. And this test is of
course used by most of the public health
laboratories and as mentioned, you know, any positive
or clinical results for Zika IgM will require
confirmation by the PRNT. And of course depending upon where the patient may have been
infected we will usually perform also dengue and chikungunya
serology. So for PRNT of course,
you know, again, serum is the preferred specimen. And only CDC or CDC approved
labs will perform this test. Really the results of the
PRNT must be interpreted in the context of the
serology results again which probably should
include either a dengue or chikungunya IgM
result depending upon where the patient might
have been infected. This test really requires
more time for completion because the basis for
interpretation is whether or not neutralizing antibodies
that are specific to Zika or the other flaviviruses
probably either West Nile or dengue or chikungunya
are present and will basically
inhibit virus growth. This virus must have
an opportunity to grow so that means it’s going to
take a little bit of time for the test to be completed. This is of course a
really gross simplification of what the assay is but
hopefully I was able to kind of at least let you all
know that this is some of the reason why it
can take quite some time for the results to come back. Of course there are
other factors that could delay the results. We, in our lab, pretty
much only ship to CDC Monday through Thursday. So if we get a result on
Friday it’s got to wait until probably Monday
for us to ship it out. So that can delay a
couple of days right there. So and also it will depend upon,
you know, what’s going on at CDC if they’ve had a large
influx of requests for PRNT. They’ve actually done an
excellent job of being able to prioritize these
samples and getting them out really quickly
as fast as they can. But, you know, don’t
be surprised if it might take a
couple of weeks for you to get these particular
test results back. And so if you think about
well I submitted my sample at the beginning of November
you may not see something until closer to the end of
November if we had to go through during both PCR – all
three, PCR serology and PRNT. So keep in mind that that
just adds a lot more time onto the actual testing time. So I’d also like to talk
a little bit about some of our partners that we’ve
hooked up with not only at the public health
level but also at the health department level. And of course many
of these when I talk about public health labs
I’m talking about state, I’m talking about local maybe
county health departments also are intimately involved
in a lot of this. We’ve actually been pretty
fortunate to have some of our private labs
contact us and let us know that they’ve brought up
RT-PCR testing capacity and have offered to
assist us with testing if our lab becomes a little
bit overwhelmed for testing. We’re actually pretty
fortunate in Texas because we have multiple
CDC Laboratory Response Network labs. We have actually
ten including ours. And they all are doing some
sort or form of Zika testing. So we have some –
we’re pretty lucky that we have some
actual built in capacity. And one thing that
we did do this week as we were receiving uro
specimens uro survey specimens in is we actually kind
of divided it up some of the specimen load and we were
able to ship samples to some of these other laboratories
so that we could kind of basically get the results
back maybe a little bit faster. In addition we’ve
actually been in contact with several commercial labs
and they are working with a lot of their public health
laboratories in their states and cities to be ready to
provide surge capacity testing in case there is something
like what happened, a large-scale investigation. But what was very helpful
about these laboratories and I think Dr. Binnicker
mentioned this in his presentation
is that, you know, these labs can provide the
ability to collect specimens in maybe some of the
lower population areas where resources may be very
limited for obtaining testing. You know, we see a lot of these
commercial labs they do have basically draw stations in
some of our smaller communities so it really it is helpful to
have them available to kind of work with us and also
be a surge capacity for us in the event that
we might need them. And I guess we also have several
military bases in the state of Texas who have also
implemented both Zika RT-PCR and IgM testing. And, you know, they stand
of course ready to assist us and provide surge capacity
in case we might need it. And of course, you know,
CDC is the main provider for PRNT in the states. But they also have a separate
lab that’s been set up to help with specifically with local
transmission and investigations. So I just want to spend a
little bit of time last thing on talking about the
efforts related to education and outreach for Zika virus and
response activities associated with cases that we’ve had. We had a large media campaign, and other states
are doing this too, where public service
announcements maybe on radio or TV maybe in multiple
languages and have really tried to use social media
sites to really allow us to reach a much broader
audience. Many health departments
whether they’re state or local or county are working with
local healthcare personnel. Many of the epidemiologists
in these health departments, you know, they work for
closely with providers and they actually have a lot
of interactions with them. And of course at the state
level one of the things that we’ve tried to do is
have meetings and webinars with a variety of healthcare
provider associations. And some of those in our state of course are Texas State
Medical Association, Pediatric Society
that we have here, also the OB/GYN Association
that we have here and our Texas Hospital
Association. We have developed really
good relationships with all of these different groups. And we’ve had the
opportunity to meet with them on several occasions and also
been invited to speak at some of their regular meetings. We also used WIC, which is the
Women’s Infants and Children, sites for distribution
of pamphlets and posting education materials. This has been very
useful for us. We’ve also had the opportunity, our state Medicaid group
has been really very good about getting out
information to providers who are Medicaid providers. And, you know, we do
have several things and I don’t actually have
this in my presentation of lessons learned about what’s
been occurring this week. You know, what we found is that
our local health departments, you know, their staff, their
epidemiologists, you know, they’ve been working these
cases now for many months in some cases almost a year. And they really know how to
interact with their providers. They’ve been invaluable
in ensuring that if a provider has a
question they’re really kind of Johnny on the spot
with information about how to collect, what to collect, what types of forms
should be filled out and also some assistance in how they should be
shipping the specimens. I think their ability
to really interact on a very intimate level with
the providers has helped us at the public health
labs be really successful in getting specimens
here to us in a manner by which we can test them. And, you know, so I really
want to say that, you know, this has really been, this
response and what’s been going on with Zika has really
been an all-hands response. laboratories, epidemiologists,
all the different types of providers and providers that
we’re really not used to working with at the public health
labs because they’re not used to sending us these types
of clinical specimens because they might use a
private or commercial lab. So I think all of these
individuals working together has really been and Dr. Binnicker
mentioned this too a real – it’s a team effort to make sure that we’re getting
the testing done. I think as we move forward in the long term one thing
we will have to look at is, you know, how will we be
treating Zika in the future? So I think with all
of the testing that we’re doing the additional
data that’s being collected that will help guide us in
where we need to go with that. So anyway I want
to thank everybody for joining the call today
and thanks for your attention. With that I’ll turn it
back over to Will Koehne. Thank you. Thank you presenters for
providing our audience with a wealth of information. We’re now going to
open up the lines for a question and
answer session. Questions are limited
to clinicians who would like information related to Zika
virus testing and laboratories. For those who have media
questions please contact CDC Media Relations at 404-639-3286 or send an email
to [email protected] If you are patient please
refer your questions to your healthcare provider. When asking questions please
state your organization and also remember that
you can submit questions through the webinar system. Operator if you’d like to
open up the phone lines, we have a few webinar
questions that I’d like to go through before we
get to the phone Q&A. But, the first one is
from Mary Anderson. She’s asking, ‘When submitting for whole blood testing what is
the preferred anticoagulant?” And she is also asking for
a specific tube collar. Hi. This is Grace Kubin. I’ll be happy to
answer that information. So when you’re submitting
whole blood for the basically for the Trioplex assay it is
a purple top tube with EDTA. All right thank you Grace. We have another one from
Southern Sumason asking, “What is the appropriate
time window to test an infant
with suspected Zika?” So would – I know
Matt Binnicker, Dr. Binnicker presented on that. Would you like to elaborate
a little bit on that? Yes. I believe it’s
within the first two days of life is what’s listed on
the CDC website but I want to make sure that Dr.
Ottendorfer for confirms that. I would concur with
the two days. There is some in the algorithm
that if there’s a possibility that they could be
screened at 18 months if, to ensure the maternal
antibodies have declined. So there’s a possibility they
could be detecting maternal antibodies and not the
infant’s and so they would need to be screened at a later point. And I’d refer back
to the algorithm. I would like to note here that there’s been a recent
study that’s been released about microcephaly that
wasn’t, or brain abnormalities, that weren’t detected at birth but they were detected
six monrto a year up to a year later. And so as we learn more
about this type of, you know, new clinical manifestation
I guess there may be updated guidance on how to test
infants going forward. Thank you. Operator do we want to – can we take a question
from the phone lines? Thank you. We’ll now begin the
question and answer session at this time over the phone. If you would like to ask a
question please press Star 1, unmute your phone and
record your name clearly. When you ask your
question please announce your organization. Your name is required to
introduce your question. If you need to withdraw
that question press Star 2. Again to ask a question
please press Star 1. The first question comes
from Frederick Walters. Your line is open sir. So hi. I had a question
in regards to the CC MAC-ELISA test. Have you guys seen any trends
with inconclusive results because we have certain samples
that the result is inconclusive. And we’ll re-collect
two to four weeks later that it will come back
inconclusive again. Have you guys seen
anything like that? So from CDC we’re actually in
the Emergency Operations Center. I would defer that
question for a follow-up with our actual laboratory
teams either in Fort Collins or
here in Atlanta. We are looking at the
test results to see sort of the person at the do confirm
and we’ll be happy to share that information with you if we
have your contact information. And this is Will Koehne,
William Koehne with CDC as well. If you’d like to if there’s
any questions that we’re unable to answer on the call today
or that we’re unable to get to please feel free to send them to [email protected] that’s
[email protected] and we’ll forward that
on to the correct parties and get you an answer. Okay thank you. Are any other speakers
or would you like to address that question? Okay operator are there
any other questions on the phone line? There are. The next question comes from I
believe it was Ana Disamuels. Your line is open. Hi. Good afternoon. We’re logging in from
Johns Hopkins Pediatrics. Our question is regarding
negative testing in an infant whose mother
had confirmed Zika virus during pregnancy. The infant in this
case would have – does have abnormalities
consistent with congenital Zika syndrome
without any other explanations. However the testing both PCR
and serologies are negative. Our concern is that
if the infection in the mother occurred
during the first trimester that negative serologies may not
exclude congenital infection. Are there any other thoughts
about the interpretation of negative serology in
this type of situation? That is an excellent question. And we may defer
this to our pregnancy and birth defects
groups that handles more of the trimester and,
you know, those results and how you should
interpret these assays. Like we’ve mentioned
the timing is critical when those specimens
are collected. I’m not sure how old
the infant was upon – has it had follow-up testing or it was just tested
at the two day point? Just at the newborn time period. However the serologies
were repeated as they were initially
inconclusive so repeat sampling was
sent from the serum again. That ended up being negative. I think this is something that for this particular case we
might try to get you in contact with our pregnancy and
birth defects team to try to help you understand if there
is another potential cause or how to follow up
with this patient. Thank you. The next question on the phone
line comes from Dr. Hudson. Your line is open sir. Thank you. This is Warner Hudson from UCLA. I’m in charge of occupation
employee health here for the health system on campus. We have a lot of travelers
coming back from Zika areas, researchers in Zika area, and live Zika research
work in our labs. And most of the UC-wide Doc
Med medical writers have been working on developing
post-exposure protocols for the labs. And of course we’re doing
testing for the travelers that come back with
questions or symptoms. And at UCLA we’re
using the Viracore test but the PCR tests
and the IgM tests. Does CDC have a plan to put together post-exposure
guidelines for lab workers, even blood-borne exposures to viremic Zika patients
in the works? Thanks. That is another
excellent question. I know that this guidance that was released
predominantly focuses on symptomatic individuals
as well as, you know, pregnant women that, you know,
those that are highest risk for, you know, complications from
Zika infection for the infants. So I’m not sure if there is
guidance planned for, you know, more of the occupational
exposure risks that may occur in otherwise, you
know, healthy adults but we will certainly take
that into consideration and bring it back to the
leadership as a request. Alright thank you. So we have a question
from the Webinar system that I’d like to ask quick. We have – the question is we
have encountered several mothers with history who travel to
Zika endemic areas longer than 12 weeks ago. Testing has been negative. Newborns are healthy at birth. What – they’re asking
what role of IgG to document earlier
exposure to the virus? What is the role of IgG to document earlier
exposure to the virus? So I guess I’ll take
this one too. As far as IgG we don’t have
a specific assay for IgG, the plaque reduction
neutralization test for once the neutralizing
antibodies develop which in my slide I didn’t
show that part of the course of illness or your, you
know, your antibody response. But at some point in
that window IgG begins to rise longer than 12 weeks. And so if you were to have that sample tested it
would probably be tested in plaque reduction
neutralization and it could be possible to detect a infection
in that sample. But I would defer to
Grace or anyone else that has more experience with samples collected
after 12 weeks. Hi. This is Grace Kubin. We don’t we haven’t
really typically tested or have been sent very many
samples after 12 weeks. I do know a few labs that
have but they don’t – some have seen a positive and
some haven’t so, you know, it’s basically just a byproduct of how good a person’s
immune system is. Right and I would agree. I mean if we’re testing the
infant here you’ll have maternal antibodies until about 18
months so it could be confounded by the mother’s antibodies
or IgG at that point. So you would want to retest
if you have either clinical or epidemiological criteria
for this infant at 18 months. All right thank you presenters. I think that’s all the time that
we have for questions today. And on behalf of COCA we
would like to thank everyone for joining us today
with a special thank you to our presenters Drs. Ottendorfer, Binnicker
and Kubin. And please feel free to contact
the presenters after the call by emailing COCA at cdc.gov
that’s [email protected] The recording of this call and
the transcript will be posted to the COCA website at
emergency.cdc.gov/coca within the next few days. We have two upcoming
COCA calls next week. On Tuesday, December 6 at 2:00
PM Eastern Time please make sure to join us for “Risk
Mitigation Strategies to Reduce Opioid Overdoses,”
part of a COCA call series about the CDC Guideline for Prescribing Opioids
for Chronic Pain. In addition, please join
us next week Thursday, December 8 at 2:00
PM Eastern time for another COCA call on Zika. This one is called “Gearing
Up for the Travel Season, How Clinicians Can Ensure
their Patients are Packed with Knowledge on
Zika Prevention.” And we have speakers from CDC
pregnancy and birth defects and CDC Zika Travelers Health
presenting for that call. All continuing education for
the COCA calls are issued through the TCEO
online the CDC Training and Continuing Education system
at www.cdc.gov/tceonline. Those who have participated
in today’s COCA call and would like to receive continuing
education should complete the online evaluation
by December 31, 2016 and use the
course code WC2286. Those who would – who will
review the call on demand and would like to receive
continuing education should complete the online
evaluation between January 1, 2016 and November 30, 2018 and they will use the
course code WD2286. To receive information about these upcoming COCA
calls please subscribe to COCA by going to the COCA webpage
at emergency.CDC.gov/coca and clicking on the joint
COCA mailing list link. Also CDC has launched a
Facebook for clinicians. Like our page at Facebook.com/cdcclinician
outreachandcommunication activity to stay connected
to the latest news from COCA. Thank you again everyone for
being part of today’s COCA call. Have a great day. That concludes today’s
conference. Thank you for your
participation. You may disconnect at this time. Speakers please stand by
for your post conference.

Reynold King

3 Replies to “Updated CDC Zika Laboratory Testing Guidance”

  1. Until Culex are acknowledged as Zika vectors and birds (esp. red-whiskered bulbuls) are investigated as reservoir hosts of Zika, nothing will change in Florida or southeast Asia. These regions (and soon, California) will be hotbeds of infection for years to come.

    Culex mosquitoes in Brazil and China are spreading Zika (which means birds are likely reservoir hosts). What's worse: Wolbachia that is acquired by any species after (or perhaps along with) a Zika infection is probably enhanced by Wolbachia.

    Wolbachia is responsible for the most widespread pandemics in the animal kingdom (LePage and Bordenstein, 2013). Safety tests were never carried out on vertebrate species prior to Wolbachia-infected mosquito releases (carried out in Brazil, Columbia, India, Indonesia, Vietnam, China, Australia, California, and Florida). It's akin to putting genetic dynamite in a species.

    Wolbachia can survive about a week in a dead host. Lateral transfers to other species have happened. This could be the reason that Zika is spreading out of control. Culex that naturally acquire Wolbachia are better vectors of malaria and West Nile virus (very similar to Zika).

    Source: "More Proof Wolbachia Infected Mosquito Releases Might Be Causing the Most Devastating Zika Infections"

    The latest finding through genome sequencing reveals Zika arrived in Florida sometime in the spring of 2016: http://www.infobarrel.com/Tracing_Zikas_Path_to_Florida_Culex_and_Wolbachia

  2. Wow…that's far on the zika virus, that's great…but…but…why so behind on COPD and diabetes etc.etc..the diseases that ARE NOT RARE…common on let's see some real advancements and some real cures for these older…real old disease….oh…they are keeped uncured by greed, as you…(CDC) allow it. I think it's time you put a stop to it and get them cured…the last cured disease was 47 years ago….that says alot about you.

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