Recent data suggest blood transfusions could transmit Zika so yes, blood banks in Zika-endemic areas should test for it. The link between maternal Zika infection and baby microcephaly () and other serious birth defects ( ) is now compelling. Were Zika-infected blood transfused to pregnant women, risk could be unacceptably high for fetuses.
Thoughis a -borne disease spread by the bite of infected mosquitoes, a steady drumbeat of data shows it can also spread by other routes.
Zika persists in semen (, ), vaginal tract ( , ) and in circulation of pregnant women ( ) for surprisingly long periods of time, and can be transmitted sexually ( , , , ). Since Zika’s asymptomatic in ~80% of those infected, Zika-infected blood transfusions could be a risk factor to fetuses not just if given to pregnant women but also if given to their sexual partners.
Preliminary data suggest blood transfusion could transmit Zika
- During the 2013-2014 French Polynesia Zika virus outbreak it was detected by (RT-PCR) in 42 of 1505 (2.8%) blood donors who were asymptomatic when they donated ( ). 11 of these 14 reported having Zika fever-like syndrome about 3 to 10 days later.
- In the US territory of Puerto Rico, a total of 68 of 12777 (~0.5%) blood donations from April 3 to June 11, 2016 were identified as presumptive Zika viremic based on (NAT) with rates rising by ~2.2 over a 9 week period during the summer (see figure below from ).
These studies revealed Zika’s potential for spreading through blood transfusion.
More recently, a couple of case reports suggest blood transfusions could indeed transmit Zika
- In Brazil (
), concentrated from the blood of an asymptomatic 54 year old man was transfused into a 55 year old liver cancer patient undergoing liver transplant.
- Four days post-transplant, the transfused recipient was serum Zika virus positive by RT-PCR.
- Suspicion fell on the platelet donor after he contacted the blood donor facility 3 days after his donation to report he’d just developed dengue-like symptoms. His stored serum sample was then tested and found positive not for Dengue but for Zika virus by RT-PCR.
- Though source of recipient’s Zika could have been other transplant related tissues and blood products, sequence analysis of 10 partial nucleotide sequences of the Zika virus isolated from the donor compared with the complete genome sequence of that isolated from the recipient matched 99.8%, strongly suggesting Zika transmission through transfusion.
- Recipient coming from a Zika non-epidemic area and being hospitalized in a mosquito-free area for 5 days before his Zika positive test further increased the likelihood he got Zika from his platelet transfusion.
- In Brazil again (
), an asymptomatic person donated platelets through on January 16, 2016. These were transfused into two different patients on January 19.
- On January 21, the donor called the blood bank to report Zika symptoms (skin rash, eye pain, pain in both knees) starting on January 18.
- Donor samples before and after donation were negative for related and by RT-PCR. However, donor’s plasma and urine samples were Zika positive 14 days after initial blood donation.
- Plasma samples from both recipients were Zika positive, 6 and 23 days post-transfusion, respectively.
Given the high risk of newborn microcephaly from maternal Zika infection, far better to err on the side of caution and start screening blood donations for Zika. This may be why on August 26, 2016, the US FDA (, emphasis mine)
‘issued a revised guidance recommending universal testing of donated Whole Blood and blood components for Zika virus in the U.S. and its territories‘.
Based on the available evidence the FDA concluded ()
‘ZIKV meets the conditions for an RTTI [relevant transfusion-transmitted infection ] as described in 21 CFR 630.3(h)(2)‘
Specifically (, emphasis mine),
‘FDA has determined that ZIKV meets the criteria in 21 CFR 630.3(h)(2) for an RTTI because of the sufficient incidence and prevalence of ZIKV to affect the potential donor population in the United States and because of the availability of appropriate screening tests for ZIKV‘ .
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