Zika Blood Screening In Puerto Rico - MMWR

[niman]

Screening of Blood Donations for Zika Virus Infection — Puerto Rico, April 3–June 11, 2016

Early Release / June 17, 2016 / 65

http://www.cdc.gov/mmwr/volumes/65/wr/mm6524e2.htm?s_cid=mm6524e2_w#F1_down

 

[niman]

Matthew J. Kuehnert1; Sridhar V. Basavaraju1; Robin R. Moseley1; Lisa L. Pate2; Susan A. Galel2; Phillip C. Williamson3; Michael P. Busch4; Jose O. Alsina5; Consuelo Climent-Peris6; Peter W. Marks7; Jay S. Epstein7; Hira L. Nakhasi7; J. Peyton Hobson7; David A. Leiby7; Pradip N. Akolkar7; Lyle R. Petersen1; Brenda Rivera-Garcia8

1Zika virus response blood safety team, CDC; 2Roche Molecular Systems, Inc., Pleasanton, California; 3Creative Testing Solutions, Tempe, Arizona;4Blood Systems Research Institute, San Francisco, California; 5Banco de Sangre de Servicios Mutuos, San Juan, Puerto Rico; 6Banco de Sangre de Puerto Rico; 7Food and Drug Administration, Silver Spring, Maryland; 8Puerto Rico Department of Health.

Corresponding author: Matthew J. Kuehnert, [email protected], 800-232-4636.

 

Edited June 17, 2016 by niman

[niman]

Transfusion-transmitted infections have been documented for several arboviruses, including West Nile and dengue viruses (1). Zika virus, a flavivirus transmitted primarily by Aedes aegypti mosquitoes that has been identified as a cause of congenital microcephaly and other serious brain defects (2), became recognized as a potential threat to blood safety after reports from a 2013–2014 outbreak in French Polynesia. Blood safety concerns were based on very high infection incidence in the population at large during epidemics, the high percentage of persons with asymptomatic infection, the high proportion of blood donations with evidence of Zika virus nucleic acid upon retrospective testing, and an estimated 7–10-day period of viremia (3). At least one instance of transfusion transmission of Zika virus has been documented in Brazil after the virus emerged there, likely in 2014 (4). Rapid epidemic spread has followed to other areas of the Americas, including Puerto Rico.

In February 2016, the Food and Drug Administration (FDA) issued recommendations for donor screening, donor deferral, and product management to reduce the risk for transfusion-transmitted Zika virus in the United States and its territories (5). In addition to behavioral- and health-risk questionnaires for blood donors in all areas, FDA recommends deferrals for donors in unaffected areas who recently lived in or visited an area with active mosquito-borne transmission of Zika virus. For establishments collecting blood in areas with active, local mosquito-borne transmission, such as Puerto Rico and other U.S. territories, the recommendations include discontinuing local blood collections and importing blood units from unaffected areas of the continental United States unless one of the following is implemented: 1) Zika virus screening of locally collected blood donations or 2) treatment of locally collected units with pathogen-reduction technology (FDA-approved only for plasma and apheresis platelets). In Puerto Rico, interventions initially were limited to importation of blood units from unaffected U.S. areas and to treatment of plasma and apheresis platelets with pathogen-reduction technology; no Zika virus screening test was available. On April 3, 2016, Zika virus screening of locally collected blood donations was implemented using a newly developed nucleic acid test (NAT) (cobas Zika, Roche Molecular Systems, Inc., Pleasanton, California) authorized by FDA under an investigational new drug application (IND) (6). As part of the IND, plasma samples from blood donors are screened individually, and specimens with reactive results are subjected to additional testing including an alternate NAT and immunoglobulin M serology. A blood donation with an initial reactive result by NAT is regarded as a presumptive viremic donor, indicating an infected donor, and is interdicted and removed from the blood supply.

During April 3–June 11, 2016, a total of 68 (0.5%) presumptive viremic donors were identified from 12,777 donations tested. The highest weekly incidence was 1.1% for the latest week of reporting, June 5–June 11, and incidence has been increasing over time (Figure).

Although the blood donor population of Puerto Rico is not intended to be statistically representative of the general population, the increasing prevalence of Zika virus nucleic acid among blood donors likely reflects an overall increase in infection incidence in the population at large. Based on data from previous outbreaks caused by arboviruses transmitted by Aedes aegypti, the high incidence often associated with these outbreaks can result in a substantial proportion of the population becoming infected. For example, chikungunya virus was introduced into Puerto Rico in 2014. Retrospective screening for chikungunya virus nucleic acid was performed on blood donations collected during June–December 2014, and the estimated detectable viremia was 0.65%, with a peak of 2.1% in October. Testing for chikungunya virus immunoglobulin M antibody of retained individual blood donation samples obtained during March 1–9, 2015, suggested that nearly 25% of the Puerto Rico population became infected during the previous year’s epidemic (7). Because viremia is only present days after acute infection, immunoglobulin M antibody can provide a more precise estimate of the burden of recent infection. The 2014–2015 chikungunya virus data suggest that detection of viremia in a relatively small proportion of blood donors each week can reflect a substantial proportion of the general population becoming infected during the course of an epidemic season.

Currently, no medication or vaccine is available to treat or prevent Zika virus disease. Prevention relies on avoidance of mosquito bites, elimination of mosquito breeding sites, community mosquito control, and taking measures to prevent sexual transmission. Screening of the U.S. blood supply using nucleic acid tests has markedly reduced the risk for transfusion transmission for multiple pathogens, including for West Nile virus after it was associated with arboviral epidemics in the United States. Measures to protect the blood supply from Zika virus, including donor deferrals, laboratory screening, and pathogen reduction technology, are expected to similarly reduce the risk for transfusion transmission.

[niman]

FIGURE. Proportion of screened blood donations reactive for Zika virus infection, by week of testing — Puerto Rico, April 3–June 11, 2016

[niman]

References

1. Petersen LR, Busch MP. Transfusion-transmitted arboviruses. Vox Sang 2010;98:495–503. CrossRef PubMed
2. Rasmussen SA, Jamieson DJ, Honein MA, Petersen LR. Zika virus and birth defects—reviewing the evidence for causality. N Engl J Med 2016;374:1981–7. CrossRef PubMed
3. Lanteri MC, Kleinman SH, Glynn SA, et al. Zika virus: a new threat to the safety of the blood supply with worldwide impact and implications. Transfusion 2016. Epub June 9, 2016. CrossRef PubMed
4. Barjas-Castro ML, Angerami R, Cunha M, et al. Probable transfusion-transmitted Zika virus in Brazil. Transfusion 2016. In press.
5. Food and Drug Administration. Recommendations for donor screening, deferral, and product management to reduce the risk of transfusion-transmission of Zika virus. Silver Spring, MD: US Department of Health and Human Services, Food and Drug Administration; 2016.http://www.fda.gov/downloads/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/Guidances/Blood/UCM486360.pdf
6. Food and Drug Administration. FDA allows use of investigational test to screen blood donations for Zika virus. Silver Spring, MD: US Department of Health and Human Services, Food and Drug Administration; 2016.http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm493081.htm
7. Simmons G, Brès V, Lu K, et al. High incidence of chikungunya virus frequency of viremic blood donations during epidemic, Puerto Rico, USA, 2014. Emerg Infect Dis 2016;22:1221–8. Epub April 2016. CrossRef PubMed

[niman]

Zika virus spreading rapidly across Puerto Rico

JOHAN ORDONEZ/AFP/GETTY IMAGES

Blood samples from pregnant women.

By HELEN BRANSWELL @HelenBranswell

JUNE 17, 2016

 

• Twitter
• Facebook
• LinkedIn
• Email
• Print

 

 

There are alarming signs the Zika virus is spreading rapidly in Puerto Rico, the Centers for Disease Control and Prevention reported Friday.

Blood banks on the island have seen a steady rise in the portion of donations that have to be rejected because they contain Zika virus. Last week, 1.1 percent of the donated units were contaminated.

If that many people are infected with Zika when they go to give blood, it’s a sign of how much virus spread there is going on in Puerto Rico, CDC Director Dr. Thomas Frieden warned in an interview with STAT.

ARTICLE CONTINUES AFTER ADVERTISEMENT

 

“What this means is that pregnant women in Puerto Rico are really at risk. That’s the bottom line here,” Frieden said.

“It isn’t that hundreds of thousands of people will die. That’s not what’s going to happen here,” he said. “It’s that we will have in Puerto Rico and potentially in parts of the US — in travelers and potentially even in some local transmission — we have terrible tragedies that will occur. Change people’s whole lives.”

READ MORE

Zika in 30 seconds: What you need to know today

Frieden said the blood bank data suggests that as many as 2 percent of adults in Puerto Rico are getting infected monthly at this point — and it’s not yet high season for transmission. Activity of mosquito-spread viruses typically peaks in the summer.

“If current trends continue, thousands of pregnant women will get infected with Zika,” said Frieden. “And there could be between dozens and hundreds of children with microcephaly born [there] in the next year.”

The CDC estimates 25 percent of the island’s population could be infected with Zika in its first year of spread there. Puerto Rican women give birth to about 3,200 babies a year.

Zika infection during pregnancy — particularly, it appears, in the first trimester — can lead to devastating birth defects.

The most notable — and the one that raised suspicions that the Zika virus could affect profound damage in developing fetuses — is microcephaly, a condition where babies are born with unusually small heads and brains that are not completely formed.

Over time, researchers in Brazil studying that country’s large cohort of Zika-affected newborns have reported other forms of brain damage, visual and hearing impairment, contorted limbs, and other birth defects, in what is coming to be known as congenital Zika syndrome.

Frieden noted it is still not clear if children who were infected in the womb but who appear physically normal at birth will experience development delays later. That has been seen with other viruses that can cause birth defects in babies born to women infected during pregnancy.

The primary focus of the CDC’s Zika response is to do all it can to reduce the risk that pregnant women will be infected. Frieden said the agency is working with local partners trying to identify effective steps that can be taken there.

HUD, the US government’s department of housing and urban development, is putting screens on the windows of public housing units, he noted. Many homes in Puerto Rico don’t have screens or air conditioning — features scientists believe will lessen the risk of wide spread of Zika virus in the continental US.

“We can’t make zero the number of infants who will be affected. But if we can reduce by 10 percent or 30 percent or 50 percent, we will have prevented that many tragedies. And that’s what we’re working to do,” Frieden said.

Health authorities in Puerto Rico have already reported one case of microcephaly there. No details were released but the pregnancy did not go full term.

Puerto Rico’s department of health reported Friday that 191 pregnant women on the island had tested positive for Zika. But a peculiarity of the disease the virus triggers means that number is almost certainly an underestimate.

The majority of people who contract Zika don’t have symptoms; it’s thought only 1 in 5 do. So it’s difficult to know how many people in affected areas have been infected.

Eventually scientists will do what’s called a sero-survey, taking blood samples from hundreds of people to look for the antibodies that indicate they were infected with Zika.

Studies done after the chikungunya virus — also spread by Aedes mosquitoes — swept through Puerto Rico showed that after the first year the virus was there, a quarter of the population of the island had been infected.

It’s too soon to do that work for Zika. Still, looking at the rate at which donated units of blood are testing positive provides a real-time hint of how many infections are taking place.

In fact, the estimate it provides is on the low side, Frieden noted, because anyone infected who has symptoms would be turned away if they tried to donate blood.

“It’s the closest thing we have to a real time pulse on what’s happening,” he said. “And what we’re finding is very concerning, because this is showing a steady and substantial increase in infections.”

MOST POPULAR

• Helen Branswell can be reached at [email protected] 
• https://www.statnews.com/2016/06/17/zika-virus-spreading-rapidly-across-puerto-rico/
•  

Follow Helen on Twitter @HelenBranswell 

[niman]

Transcript for CDC Telebriefing: Zika Update

 

Recommend on FacebookTweet

Press Briefing Transcript

Friday, June 17, 2016, 10:00 a.m. ET

• Audio recording[MP3, 6.9 MB]

Please Note:This transcript is not edited and may contain errors.

OPERATOR: Welcome and thank you for standing by.  I would like to remind parties that your lines have been placed on listen only until the question and answer portion of the conference.  If you're wishing to ask a question, press star followed by one on the key pad of your telephone, and please be sure that your telephone is unmuted and clearly record your name at the prompt so that your question may be introduced.  Today’s conference is being recorded.  If you should have any objection, you may disconnect at this time.  It is now my pleasure to turn the call over to Mrs. Kathy Harben.  Thank you, you may begin. 

KATHY HARBEN: Thank you, Emily and thank you all for joining us this morning for this update on Zika virus, specifically the MMWR on the screening of blood donations for Zika virus infection using an investigational nucleic acid test in Puerto Rico.  Joining us today is CDC Director, Dr. Tom Frieden and Dr. Matt Kuhnert, Director of CDC’s Office of Blood, Organ and Other Tissue Safety.  Dr. Frieden will provide opening remarks before the Q&A Dr. Kuhnert will also have a few remarks.  I’d now like to turn the call over to Dr. Frieden. 

TOM FRIEDEN: Thank you for joining us today.  Summer is heating up and so is Zika.  We’re sharing information on what may be our most accurate real-time leading indicator of Zika activity in Puerto Rico.  I’ll give you the bottom line upfront.  Based on the best information available, Zika infections appear to be increasing rapidly in Puerto Rico.  The implication of this and the real importance of this information is that in the coming months it's possible that thousands of pregnant women in Puerto Rico could become infected with Zika. This could lead to dozens or hundreds of infants being born with microcephaly in the coming year and for the thousands of other infants born to women infected with Zika who don't have microcephaly, we simply don't know and may not know for years if there will be long-term consequences on brain development. Let me go back to what's being done and emphasize that this is part of a blood safety program which is keeping Zika out of the blood supply in Puerto Rico.  So even though there's an increase in infection rates, there's no known risk from transfusion because of this highly sensitive test being used.  Since April 3, blood centers in Puerto Rico have screened locally collected blood for Zika, using a highly accurate nucleic acid amplification test, this is a test that measures for the actual virus in the blood.  It’s highly sensitive and highly specific.  Screening blood that's donated for Zika protects the safety of patients and keeps the blood supply safe.  At the same time, it gives us a window to see what's happening in infection rates generally, even though it's not a random sample of society.  To date, there have been no confirmed cases of Zika spread through a blood transfusion anywhere in the United States or Puerto Rico and the other territories.  A total of 68 out 12,777 blood donations in Puerto Rico have tested positive for Zika.  That proportion has steadily increased.  If you look at the graphic you can see a steady line upwards with infection rates.  The highest percentage is the most recent week, 1.1 percent just last week, the week ending June 11th.  Now although the blood donor population doesn't represent the general population, the increasing prevalence of blood donations that test positive for Zika likely reflect an overall increase in the infection in the population at large.

Let me take a moment to clarify what this means.  This is a test that measures whether someone is infected at the moment.  They have virus in their blood.  It’s not a test of whether they've been infected in recent months.  We don't know precisely how long the virus stays in the blood by this particular test.  By other tests, it's just a few days.  This is more sensitive, so it may be a week or two.  The result of that is that a 1 percent positivity rate at any given time translates into a more than 1 percent, perhaps 2 percent, we don't know exactly, rate of infection each month.  This means that over the course of many months, for example, a nine-month pregnancy, there would be a substantial chance that a woman would become infected.  I would reiterate that all donations that test positive are removed from the blood supply and donors who test positive get information about how to avoid spreading Zika to others.  The increase in blood donations testing positive in Puerto Rico is concerning.  It likely reflects an increase in the general population, but our concern here is about protecting pregnant women.  With this rate of infection, the possibility that there could be thousands of pregnant women infected leading to dozens to hundreds of affected babies is what's of most concern. 

We’re working intensively in addition to keeping the blood supply safe with the Puerto Rico health department, the government, communities, and people throughout Puerto Rico to provide services for pregnant women; Deet, long sleeves, measures in their homes that might reduce their risk of getting infection, as well as to control the mosquitos.  Controlling this mosquito is very difficult.  It takes an entire community working together to protect a pregnant woman.  We can't make the risk zero.  We know that between Puerto Rico and the continental U.S. there have been more than 400 women identified who have likely Zika infections in pregnancy.  Sadly, some of those pregnancies will result in affected infants.  We can't make that risk zero but even if we can reduce it by 10 percent or 30 percent or 50 percent, that is a significant number of tragedies that we can prevent and we're doing everything we can to do that.  Our priority remains to protect pregnant women.  I’ll turn it over to Dr.  Kuhnert to talk more about the testing and how that is protecting the blood supply.  Matt? 

DR. MATT KUEHNERT: Thank you, Dr. Frieden.  The test being used to screen blood in Puerto Rico is extremely accurate.  It’s most effective, as Dr.  Frieden mentioned, at identifying recent infection to protect the blood supply.  Just to give some further insight on test accuracy, there is one blood center that's testing in the continental U.S.  They have not seen any false positive results to date, and no positives at all which makes sense since there's currently no Zika-affected areas in the continental U.S. They've tested more than 9,000 donations.  So this is a very good indicator of the accuracy of the test.  I just wanted to also summarize the blood safety issues.  Mosquito-borne diseases can be transmitted by blood transfusion.  We’ve seen that in multiple examples.  And to protect the blood supply, U.S. blood donors are routinely screened by questionnaire and by laboratory tests for risk of transmittable diseases. 

Transfusion-transmitted infections have been documented for several mosquito-borne diseases including West Nile virus and Dengue virus -- there's a strong possibility that Zika virus could be spread through blood transfusions.  There’s been at least one case of Zika transmission by blood transfusion in Brazil.  In areas without active transmission, such as the continental U.S., there are blood donor deferrals in place, excluding people who travel to Zika-infected areas and also excluding those with sexual contact with those who travel.  But this isn't enough to identify Zika- infected donors in areas that have active mosquito-borne transmission of Zika virus because many won't have symptoms or will only have mild symptoms and won't know they've been infected. So laboratory testing of Zika virus is necessary because many donors won't have had symptoms.  Through the interventions we have in place, the blood supply is being protected in Puerto Rico and through deferrals being protected in the continental U.S.  I’ll turn it back to Dr. Frieden for a few summary remarks before Q&A. 

TOM FRIEDEN:  Thank you very much Dr Kuehnert.  Again, the bottom line is we're seeing a steady increase in infections in blood donors.  That blood is being removed from the blood supply, so there's no reason to think that there's a risk of Zika from blood transfusion in Puerto Rico or anywhere else, but it does reflect a concerning trend in Puerto Rico.  The priority is to protect pregnant women, to reduce the number of infants affected with microcephaly. That’s going to take the whole community - anything we can do to reduce those numbers will be critically important.  We know we can't make them zero but everything we do to bring them down will be crucial.  One of the challenges of combatting Zika is that the consequences of infections today will not become apparent for many months. That’s something which makes it challenging, but also makes us want to ensure that we're doing everything possible now so that we don't look back in three, six, or 12 months and say we wish we had done more back in June.  I’ll stop there and I think Kathy Harben will open it up for questions. 

KATHY HARBEN: Yes, thank you, Dr. Frieden and Dr. Kuhnert.  Emily, we're now ready to open up the line for Q&A. 

OPERATOR: Thank you.  at this time, anyone wishing to ask a question or make a comment, please press star, followed by one on the key pad of your telephone, and please be sure your telephone is unmuted and clearly record your name at the prompt so that your question may be introduced.  Once again, it is star followed by one to ask a question.  One moment, please, for the first question. 

OPERATOR:  Our first question is from Mike Stobbe from the Associated Press. 

MIKE STOBBE Hi.  Thank you for taking my call.  A couple questions if I may.  First, Dr. Frieden, you talked about what may be coming in terms of case numbers of pregnant women and affected babies and fetuses.  Could you walk us through what the projection is, the curve that's ahead of us?  Is it over the summer that you think -- when do you think cases will reach their highest, for how many months ahead do we expect to see increases?  And also could you remind us, when did Puerto Rico start using the test that Dr. Kuehnert was talking about?  When did that first go into use? 

TOM FRIEDEN: First off, we don't have a crystal ball so we can't predict exactly what will happen. The two viruses spread by the same mosquito, Dengue and Chikungunya, generally peak over the summer and into the fall months. We’re not at the peak yet of the traditional time.  If you look at what Chikungunya did the most recent virus to be introduced into Puerto Rico before Zika, the peak was over the summer months with the high rates going into the fall.  So we haven't yet hit what is the traditional peak.  We find that if, say, 20 percent to 30 percent of people become infected in a year, there are 32,000 births a year in Puerto Rico, even if the risk is limited to the first trimester, that's still thousands of infants at high risk of Zika.

Our best estimate based on data from other countries is that of women infected in the first trimester, between 1 and 13 to 15 percent may have infants born with microcephaly.  That’s where the estimates of potentially thousands of pregnant women, potentially dozens to hundreds of affected infants.  Of course, we need to do everything possible to reduce that number.  We also don't know for the infants born without microcephaly who were exposed to Zika in utero, whether there will be any long-term consequences and that's something that we may not know for some time.  I think I said April 3 was the date of the start of testing.  This is a new assay it was approved by the Food and Drug administration. It seems to be performing extremely well, both in terms of sensitivity and specificity.  It’s highly effective at picking up relatively small amounts of the virus in the blood, and we are not aware of false positives so far. 

OPERATOR: Thank you. Our next question comes from Lisa Schnirring with CIDRAP News. 

LISA SCHNIRRING: Hi, thanks for being available today.  Great information.  I am wondering where this test is being used in the United States.  That was good information, but it would be interesting to know where, if it's in kind of one of the vulnerable areas.  Thanks much. 

TOM FRIEDEN: Dr. Kuehnert? 

DR. KUEHNERT: Sure, I can take that question.  Thank you.  Currently, the test is only being used in the continental U.S. by Gulf Coast Regional Blood Center in Houston.  They put out a press release that they were doing so and started testing on May 23rd.  As I mentioned in my comments, they've tested over 9,000 donations with no positives to date.  Gulf Coast area of collection is in east Texas, including Harris County and the Houston area.  There are other blood centers who are also planning to start screening, even though there's no active transmission of Zika in the continental U.S.  They’re getting prepared, and so the blood centers are in those higher risk areas that you're probably thinking about in Texas and Gulf Coast states and Florida.  Thanks. 

LISA SCHNIRRING:  Thank you. 

TOM FRIEDEN:  I’d add that other blood centers are also considering adding screening in the coming days and weeks. 

OPERATOR: Our next question comes from Lena Sun with the "The Washington Post." 

LENA SUN: Thank you.  Two of my questions were already answered, but I do have a follow-up to this last one.  So how many other blood centers are we talking about that might be -- that are considering adding screening in the coming days and weeks? 

TOM FRIEDEN: Dr. Kuehnert? 

DR. KUEHNERT: There's not really a list.  There’s no requirement to test at this time with laboratory screening.  As I mentioned, all the blood centers in the United States already do screening through deferrals through travel and deferrals, so the blood supply is being made safe through that.  As I mentioned, there are some centers who, on their own, have selectively decided to consider testing.  That’s a decision of theirs and they have not made that public. 

LENA SUN: So it's not a requirement by the government, right? 

DR. KUEHNERT: That's correct. 

TOM FRIEDEN: That's correct.  And I would just reiterate the FDA did advise and all blood centers have been deferring donations from people who have traveled to Zika-affected areas, so we wouldn't expect to see positives at this point or a risk to the blood supply. 

LENA SUN: Okay, thank you. 

OPERATOR: Thank you, our next question comes from Julie Steenhuysen from Reuters. 

JULIE STEENHUYSEN: Hi. Good morning.  Two questions. The test that is being used in Puerto Rico and the lab in the United States, is that the Roche test that the FDA approved for use in March?  And if I’m right, if it is the Roche test, wasn't that only approved for areas with active mosquito-borne transmission?  How is it that it could be used in Florida?  Can you sort that out for me, please? 

TOM FRIEDEN: It is the Roche test in Puerto Rico, and Dr. Kuehnert will answer the test that's being used in Texas right now. Dr. Kuehnert?

DR. KUEHNERT: The test is being used in Texas currently, not in Florida.  It’s through an investigational new drug application that FDA authorized.  Although the recommendation by FDA is that the test be used as an option in Zika areas where there is active transmission of Zika, there is an option for blood centers anywhere to use it.  I also wanted to just step back a bit about Puerto Rico and the blood supply, that initially when the threat of Zika first emerged, that FDA put out recommendations to say that in an area of active transmission, that blood centers should either use pathogen-reduced blood through a pathogen reduction technology which is only FDA approved for – it freezes platelets and plasma, to use a screening test, or to outsource the blood.  Until the Roche test was available, the option was only to outsource blood because there's very -- most blood transfused are red cells which is not FDA-approved for pathogen reduction technology. Until the Roche test was available, that's what occurred.  On April 3rd, the test became available.  To answer your question, again, if a blood center elects to test using the Roche assay, they are free to do so. 

JULIE STEENHUYSEN: I have one follow-up.  You’re talking about for the rest of the centers basically are using deferral which counts on people who have traveled to a Zika-affected area being honest, right?  Is there any risk, and has that been considered? 

DR. KUHNERT: There’s always a risk of a blood donor not answering a question accurately, either intentionally or unintentionally.  However, the risk is quite low.  There is always a risk with blood collection, whether you're talking about Zika or you're talking about HIV.  There is risk, but it's very, very low. 

TOM FRIEDEN: Just to clarify, the very, very low there is in the 1 per -- matt, would you say millions for some of the rare infections?  As with any product or medication, we always balance the anticipated risks against the anticipated benefits.  For many conditions of blood transfusion it can be lifesaving or crucially important. 

KATHY HARBEN: Next question, please? 

OPERATOR: thank you. Our next question comes from Sandee Lamotte from CNN. 

SANDEE LAMOTTE: Hi there.  Thanks for taking my question.  Dr. Kuehnert, when it comes to the blood screening, talk to me about the aspect of blood not being actually positive for the Zika, is that a problem or not? 

DR. KUEHNERT: I think what you're asking about is a false negative.  So in other words, Zika virus being there and it not being detected.  As Dr. Frieden mentioned and I reiterated, this test is very, very sensitive.  So this gets to the sensitivity of the test.  The analyses that have been done have shown that the test detects even a few copies of virus per milliliter of blood.  So it is very unlikely that a donor with Zika infection is going to be missed through screening.  It is possible.  It’s very, very early in the infection and there's very few viral copies in the blood stream but very unlikely. 

SANDEE LAMOTTE: Thank you.  A follow-up.  Is there additional cost for these blood centers in Houston and other places to do this extra testing? 

DR. KUHNERT: Under the FDA authorized IND, there is a charge of cost recovery for the test.  I defer to Roche, I think, on what that amount is or the blood centers to fill you in.  But it's a few dollars per unit. 

SANDEE LAMOTTE:  thank you.  Dr. Frieden, you mentioned earlier that you're very careful to determine that the donor population in Puerto Rico is not indicative of the general population.  Talk to us again about why you are doing this generalizing to the various -- the general population and your worry about the numbers of pregnant women that will be infected. 

TOM FRIEDEN: we do believe, based on what has happened with other viruses that the blood donor population gives us our most real-time leading indicator of what is happening with infections in the population as a whole.  Even though it's not a random sample or a systematic sample, it's a large number of people being tested from all walks of life.  It’s geographically clustered in some places where people come in to donate blood.  In the prior introduced virus Chikungunya, we were able to correlate quite closely what happened with blood donors with what was happening in community surveys of prevalence more generally.  Strictly speaking, it is not a serosurvey but it serves that purpose to a significant extent. 

TOM FRIEDEN: let's go to the next question, please. 

OPERATOR: Our next question comes from Dan Vergano from Buzzfeed news. 

DAN VERGANO: I was wondering if you can follow up on that a little bit.  How does this pattern of infection match Chikungunya in the past?  Where would you expect to top out in past outbreaks of mosquito-borne virus?  If it's 2 percent of the population weekly infected, in 50 weeks you have the entire population having suffered an infection.  How does that actually play out? 

TOM FRIEDEN: We don't have a crystal ball, as I said, and we can't predict what will happen.  with Chikungunya, about a quarter of the population became infected in less than the first year after introduction of the virus, and that these blood results suggest a similar level of infection, but that depends on what happens in the coming months and what can be done to both control the virus and protect pregnant women from infections.  The difference here, and it's very important to emphasize that the priority in Zika is to protect pregnant women. In Chikungunya, you have an infection that's very painful, that's very apparent, where most people have symptoms, so that appears very differently to people in a community where it's spreading broadly.  Here the risk is a risk somewhere between a few months and nine months from now when women who are pregnant and become infected with Zika deliver babies who might be affected by microcephaly or might have a more subtle but also problematic birth defect.  So the numbers here are consistent with what happened with prior infections that spread widely through Puerto Rico.  Only time will tell for sure, but it's certainly very concerning because of the risk to pregnant women. 

DAN VERGANO:  If I can follow up, can we assume that the 1.1 percent who are testing positive are people with mild or no symptoms at all and somebody with obvious symptoms would have been screened out of this test prior to donating blood? 

TOM FRIEDEN:  Yes, that's exactly right.  These are people who didn't have any symptoms or didn't yet have any symptoms when they were screened. 

DAN VERGANO:  Thank you. 

OPERATOR: Thank you, our next question comes from Meg Tirrell with CNBC. 

MEG TIRRELL: Hi guys.  I’m wondering if you can help us understand the difference between this Roche test specifically for the blood supply and the quest diagnostics test that approved by the FDA for emergency use for patients who might have Zika.  Help us understand why one would be used for one situation and not the other. 

TOM FRIEDEN:  I’ll start and then Dr. Kuehnert may want to amplify.  The Roche test is highly sensitive so it's going to find even tiny amounts of virus in the blood.  In the test that's done in the CDC Trioplex PCR that is provided to state and local health departments that tests for not only Zika but also Dengue and Chikungunya and the quest test which tests just for Zika are less sensitive tests.  They appear to work better on urine, at least the CDC test, than blood, where the number of viral copies may be higher.  They’re used for individual patient diagnosis as opposed to a screening test for the blood supply.  Dr. Kuehnert? 

DR. KUEHNERT: Just to clarify the question did you say the quest diagnostic test?  Is that an antibody test? 

TOM FRIEDEN:  Quest has a PCR approved by FDA for Zika.  So it was comparing the Roche test with the quest test.  The bottom line is Roche is for the blood supply, Quest is for patients who have symptoms or are concerned that they may have been infected in the past week or two. 

DR. KUEHNERT:  I don't have anything to add to that, thank you. 

MEG TIRRELL: If I can follow up quickly.  I understand that they are approved for different things, but I don't understand just why you wouldn't use the super sensitive Roche test in patients.  Is it more expensive?  Would it turn up more than you need to?  I’m just confused by that. 

TOM FRIEDEN:  I think what we're doing now is looking at all ways to optimize the tests that are out there.  Some of it involves how much blood is drawn and how the tests are done, but the fact that the Roche test is so sensitive is something that we're looking at closely to see if we can tune the CDC assay to make it more sensitive.  For the time being for the CDC assay, which has already been sent to more than a hundred labs around the U.S. and nearly a hundred countries around the world, what we have found is that the urine test is much more accurate, much more sensitive, than the blood test, that the likelihood of getting a positive in people who are infected in those first two weeks is very high if urine is obtained.  So we've been informing physicians and those ordering the test and drawing the test to get both blood and urine because the urine will often be positive for individual clinical diagnoses not related to the blood supply and we're also looking at enhancements in the test to try to increase its accuracy and sensitivity. 

MEG TIRRELL: Thanks. 

OPERATOR: thank you. Our next question comes from Maggie Fox from NBC news. 

MAGGIE FOX: Thanks very much.  I’m sorry if I’m repeating a question that's been asked already, but can you talk about how much this tells you about the percentage of people who have symptoms versus the percentage who don't have symptoms from Zika?  Thanks. 

TOM FRIEDEN: This is not able to give us information on that question.  The information from the past seems to be that about four out of five people with Zika have no symptoms.  Confirming that in the present is quite challenging because there's no simple way to do it.  But we do know from the data that came out earlier this week definitively that even women who don't have symptoms of Zika can give birth to infants with microcephaly. 

MAGGIE FOX: Can I just follow up and ask you, is there any way that you're going to be able to follow up on that show and find out the percentage of symptomatic versus asymptomatic people?  Thanks. 

TOM FRIEDEN:  That's something we will consider in the future.  Right now our priority is to protect pregnant women, reducing risk in every way possible. 

DR. KUEHNERT: Could I add something?  For blood donors, there is follow-up in order to measure the accuracy of the test with laboratory testing.  Also, there will be a study plan to follow up the donors, and that will include a symptom questionnaire, both for symptoms that developed after donation.  In addition, just routinely donors are asked to call the blood center back if they develop symptoms, so there's that data as well. 

MAGGIE FOX: Thanks. 

OPERATOR: As a reminder, anyone wishing to ask a question or make a comment, please press star followed by one on the key pad of your telephone and record your name at the prompt.  And our next question comes from Meghan Rosen with Science News. 

MEGHAN ROSEN: Hello.  Thank you for taking my question. I just wanted to know if the Roche test was PCR based and if not how does it work? 

TOM FRIEDEN:  Yes, it is PCR based. 

MEGHAN ROSEN: Thank you. 

TOM FRIEDEN: I think we have time if there are one or two more questions, we have time for one or two more and then we'll wrap up. 

OPERATOR: Our next question comes from Mike Stobbe with the Associated Press. 

MIKE STOBBE: Thanks for hearing me again.  Yesterday, the CDC released for the first time information about pregnancy outcomes in pregnant women who had been infected in the 50 states and the District of Columbia. There wasn't such information for the territories.  Since we're talking here about what's anticipated in Puerto Rico, could you share with us what's been seen so far.  How many pregnancies, what outcome data do you have on those?  And if I may, I also wanted to ask you could you say anything else about how you think this would play out in the mainland USA if mosquito transmission and outbreaks occur, what would be the operating procedure for blood donations when that first happens in Florida or Texas or wherever an outbreak occurs? 

TOM FRIEDEN: First, I believe we hope to begin reporting information on pregnancy outcomes in territories starting next week.  It’s a weekly report.  It just is not ready for the territories for this week.  I would emphasize that we don't anticipate seeing the majority of the outcomes yet because the infections are relatively recent.  So between infection and pregnancy outcome, there's obviously a delay, particularly if, as we believe the highest risk of microcephaly is in the first trimester.  In terms of blood screening in the continental U.S., I’ll ask Dr. Kuehnert to address that. 

DR. KUHNERT: Yes, thank you for the question.  There is a comprehensive plan for state and local health departments to communicate with blood centers about areas of active transmission in their localities. The FDA recommendations point to the CDC website where such information will be posted so that all blood banks can work through deferrals and laboratory screening to make the blood supply safe.  For the converse, if blood centers choose to test and they have a positive, they're instructed to inform the state and local health department immediately, and we will also be notified.  In summary, there is a plan for blood safety if there's local transmission in the continental United States and Hawaii. 

KATHY HARBEN: Next question? 

OPERATOR: our next question comes from Marc Santora with the "New York Times." 

MARC SANTORA: Hi. On the subject of testing broadly, I was just wondering how much progress there is in having a commercial test available for the antibody test which it would seems to me would make it a lot easier to make testing of pregnant women a part of routine care. 

TOM FRIEDEN:  thanks.  We’re making progress there on a few different fronts.  There are several companies that are pursuing emergency licensure of new tests for IGM.  That’s the antibody test.  In addition, CDC laboratory experts have established a way of producing large numbers of the IGM product using particles.  This is a way of producing large batches safely, and we're now working with the FDA to get those approved.  We’re in the process of -- in discussions I should say with many of the private labs to offer this test as a technology transfer in the coming weeks.  So we hope that within several weeks to a month or two it will be becoming available in the private sector in addition to the current availability in the public sector through public health laboratories.  I would highlight the fact that the testing we have for Zika is helpful but it's not perfect.  We can't always distinguish Zika from other infections in people who have lived in areas where dengue and other related viruses are present.  We don't have a way of reliably diagnosing infection that occurred two months or more previously so these are some of the things that are needed in terms of technological advancements.  But in terms of the operational details of getting testing more widely available, we've been able to make a million tests at CDC.  We’ve provided them to public health labs throughout the U.S.  and the country and the world rather, and we're working to transfer them to private sector laboratories to increase availability throughout the healthcare system. 

KATHY HARBEN:  I think we have time for one question if there is one. 

OPERATOR: Thank you.  Our next question comes from Akshay Ganju with ABC News medical unit. 

AKSHAY GANJU thanks for taking my question.  i was just quickly hoping you could repeat the total number of positives that you had seen in your blood testing in Puerto Rico. 

TOM FRIEDEN:  In Puerto Rico, a total of 68 positives have been seen with the highest percentage in the most recent week of June 5th to 11th.  If you look at the MMWR report itself, you can see the graphic showing a steady increase since late April in the proportion positive.  This again is a point in time of virus in blood.  The concern here is when we translate that into an exposure over multiple months it is many times that 1 percent rate.  That’s why we're so concerned about pregnant women and protecting pregnant women.  I’ll just close here with reiterating the bottom line, that the blood supply is being tested in Puerto Rico.  Blood donors are being screened in the U.S.  Any positive blood samples are removed from the system, so we don't think there's a risk to the blood supply, but it does, we believe, reflect an increase in Zika in Puerto Rico, and this could mean thousands of pregnant women in Puerto Rico infected, and that in turn could lead to dozens to hundreds of affected babies born in Puerto Rico in the coming year.  We’re working very intensively with our health department, government and community colleagues in Puerto Rico to provide services for pregnant women to reduce their chances of getting infected and to control mosquitos.  This takes a whole community, and although we know we can't make the risk zero, we can reduce it some by 10 or 30 or 50 percent, every infant with microcephaly that doesn't occur, is a tragedy prevented.  We’re doing everything we can to reduce the risk of that outcome. Our priority remains to protect pregnant women because we don't want a few months from now when babies are born with birth defects that we look back and say there's more we wish we had done now. Thank you very much.  I’ll now turn it over to Kathy Harben to close the call. 

KATHY HARBEN.  Thank you, everyone, for joining us.  This includes today's telebriefing.  A transcript of this call will be posted to the CDC newsroom website as soon as possible.  If you need additional information or have other questions, you can call the CDC press office at 404-639-3286. or e-mail us at [email protected]. 

OPERATOR: this concludes the CDC conference.  Thank you so much for joining.  You may disconnect at this time.  

###
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

 

 

File Formats Help:

How do I view different file formats (PDF, DOC, PPT, MPEG) on this site?

• Audio/Video file

• Page last reviewed: June 17, 2016
• Page last updated: June 17, 2016
• http://www.cdc.gov/media/releases/2016/t0617-zika.html
•  

[niman]

Audio

http://www.cdc.gov/media/releases/2016/t0617_zika.mp3