Universal Zika Testing of Donated Blood, Blood Products Recommended by FDA

Troy Brown, RN

August 26, 2016

The US Food and Drug Administration (FDA) has recommended universal testing of donated whole blood and blood components for Zika virus in the United States and US territories.

"We're taking this step to further enhance the safety of the blood supply," Peter Marks, MD, PhD, director of the FDA's Center for Biologics Evaluation and Research, said in an August 26 news conference.

"The recent outbreak of Zika virus represents a rapid expansion of the spread of the virus in the Americas and the Pacific Islands. Currently, more than 50 countries and territories are experiencing active transmission of the virus. Since the primary mosquito vector for Zika virus is present throughout much of the southern portion of the United States, local mosquito-borne transmission is possible, and we've already seen it in Florida."

In Florida, one positive blood donation ― from an infection that was likely travel related ― has been identified using an FDA-authorized investigational test, and others are being investigated, Dr Marks said. The infected blood was identified within the past 2 weeks and was kept out of the blood supply, demonstrating that the system is working, he added.

The new guidance revises recommendations issued by the FDA in February. In the initial recommendations, the agency asked that regions with active Zika virus transmission screen whole blood and blood components for Zika virus, use pathogen-reduction devices, or stop blood collection, and only obtain whole blood and blood components from regions of the United States with no active virus transmission.

Now, the agency recommends screening blood and blood products in all states and territories of the US with a test authorized by the FDA under an investigational new drug application, or a licensed test when one becomes available. For plasma and certain platelet products, an FDA-approved pathogen-reduction device may be used.

"After considering all of the available scientific evidence, FDA believes that the use of investigational testing or the use of pathogen-reduction devices for certain blood products currently represents the best way to ensure the safety of the blood supply. The recommendations will need to be implemented immediately in locations with active mosquito-borne transmission, and these include Florida and Puerto Rico, where testing is already underway," Dr Marks explained.

The recommendations must be implemented in 11 other states (Alabama, Arizona, California, Georgia, Hawaii, Louisiana, Mississippi, New Mexico, New York, South Carolina, and Texas) within 4 weeks, and the rest of the country must implement these measures as soon as possible, but no later than within 12 weeks.

"The rationale for this staged implementation plan is to facilitate the maximum protection of public health allowing for the orderly introduction of testing or pathogen reduction to the approximately one million units of blood components collected from blood donors each month."

To date, more than 8000 travel-associated and more than 2000 non-travel-associated cases of Zika virus have been reported in the United States and its territories. There is a risk that asymptomatic individuals could potentially donate blood and transmit the virus. Screening of blood products in Puerto Rico detected an average rate of Zika infection in 0.5% of presumptive donors between April 3 and June 11, 2016, according to a recent report in Morbidity and Mortality Weekly Report, with a high of 1.1% in the last week of the study period.

"The potential for sexual transmission also adds another layer of complexity to the Zika virus outbreak," Dr Marks said. Infected men may transmit the virus to sexual partners for several months, and infected women may transmit it to their partners for "a few weeks." Moreover, those who have contracted the virus through sexual transmission may be unaware that they are infected and donate blood.

Many infected individuals may experience minor symptoms or be unaware that they are ill; however, the most serious outcomes occur when a pregnant woman's unborn child is exposed to the virus. These infants may experience microcephaly as well as other severe defects of the brain and joints.

"Thus, transfusion of a pregnant woman with blood infected with Zika virus could have terrible consequences. Alternatively, contact with a male sexual partner who's infected with Zika virus could also have similar consequences. Given the potential for Zika virus to have such serious consequences, FDA has worked with industry to make investigational nucleic acid tests available in the United States," Dr Marks explained.

If a blood donor reports a recent history of Zika virus infection, they should be deferred from donating blood or blood products for 120 days after either a positive viral test or the resolution of symptoms consistent with the virus, whichever is longer.

It is unclear how much testing for Zika virus in donated blood will cost; however, this testing will be added to current testing of donated blood.

FDA news release. Full text

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