Researchers already know the Zika virus can be sexually transmitted. But what they didn't count on was that men who might donate semen to a sperm bank could be infected without knowing it.
“When semen is donated, it can be stored frozen for significant periods of time," Dr. Peter W. Marks, the director of the FDA's Center for Biologics Evaluation and Research, told the New York Times. "And that doesn’t necessarily inactivate the Zika virus.”
Because there's not yet a vaccine to protect us from Zika, the World Health Organization recommended in 2016 that women in areas affected by the virus should avoid getting pregnant to prevent the possibility of birth defects known to be associated with the mosquito-borne disease.
Babies born with birth defects such as microcephaly have been helping researchers learn more about the effects of the virus, but there's still so much they don't know. In at least one country where Zika was prevalent in 2016, fewer babies were born with microcephaly, and doctors are still looking at why. But they believe it's possibly because women heeded the government's advice about not getting pregnant during the epidemic and that more women terminated pregnancies if they thought they were at risk.
There have been cases of babies born in the U.S. with birth defects because the mother was infected with the virus while pregnant. The CDC also has been closely monitoring plenty of pregnant women who have showed signs of Zika or tested positive even though they didn't have symptoms. Many of those women being monitored live in Puerto Rico.
To be clear, there are no suspected cases of donor semen being infected in Florida so far, according to the CDC. But the CDC did find that in the South Florida area near Miami, there were “cases of people who are residents of Palm Beach County and Broward County in which the exposure was uncertain.”
What does that mean exactly? Some people who may have donated semen to sperm banks may have been exposed to Zika without knowing they were exposed, whether they had the virus or not. The reason for the concern about sperm banks stems from the fact that out of more than 300 cases of Zika in Florida, according to the Florida Health Department, the transmission location (aka how someone got it) in 38 of those cases is undetermined. So it's possible that could be the source, and the Florida Health Department just wants women who are planning to use donated sperm from any of the county's 12 sperm banks to proceed with caution.
There isn't a test yet that sperm banks can use to detect the virus in semen, so doctors say if you're going to use a sperm donation that was collected on or after June 15, 2016, you should have a conversation with your provider about the potential risks.