Following the French Polynesian Zika virus (ZIKV) outbreak in 2013–2014 it was found that a significant proportion (3%) of blood donors were viraemic. Since ZIKV has moved to Martinique at the end of 2015, the French Blood Bank has started systematic individual nucleic acid testing (NAT) of blood donations. Between January and June 2016, 4129 consecutive blood donations were tested (mean age 41.9 years, sex ratio [M/F] 0.88). Positive NAT detection occurred in 1.84% of donations, with the highest detection rate (3%) occurring during weeks 17–20. Donors were contacted at day 7 postdonation to identify symptoms compatible with ZIKV infection and if they had no signs they were called again 14 days following donation. 75 viraemic donors were called with 45.3% of them remained asymptomatic and 54.7% reported symptoms such as fever, conjunctivitis, myalgia, arthralgia and rash. Symptomatic vs. asymptomatic donors tended to have higher viral loads (5.36 vs. 4.93 log10 copies/mL). This could be due to different timing of sampling occurring. The range of viral loads (2.09–6.50 log10 copies/mL) was similar to that seen in French Polynesian asymptomatic blood donors. The authors also performed seroprevalence analyses in 418 donors in March and in 176 donors in June. The seroprevalence after neutralisation was 13.5% in March and 42.2% in June. Therefore ZIKV individual NAT screening in Martinique allowed for the detection of 2% of contaminated blood donations, with the proportion of asymptomatic cases being 45%. The duration of plasma asymptomatic and presymptomatic viraemia appeared to be about 6 days.
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