Updates from the Pacific Coast Reproductive Society Conference - Protecting Babies from Zika

In mid-March, reproductive endocrinologists, embryologists, and other fertility experts met in Palm Springs for the 66th Annual Meeting of the Pacific Coast Reproductive Society (PCRS). Here is a brief overview of a few topics covered by presenters at the meeting.

Protecting Babies from Zika

What is Zika?

Transmitted mostly by mosquito bites, Zika can also spread through sex and from a pregnant woman to her fetus. The disease may also spread through blood transfusions. At this time, there is no medicine or vaccine for Zika virus. The best way to prevent its spread is to protect against mosquito bites and, if infected, to avoid sexual transmission by using condoms or not having sex.¹

In adults, Zika may cause mild symptoms or none at all. Lasting up to a week, common symptoms are fever, rash, headache, joint or muscle pain, and red eyes. In infants, however, it can be a completely different story. A baby exposed to Zika during pregnancy may develop severe brain and other defects such as an abnormally small head (microcephaly.) It's very important for pregnant women to avoid traveling to areas where there is a higher risk of Zika, most often outside the continental U.S. Although mosquito-borne Zika transmission has been reported here, it is not yet common.¹

Learning from an epidemic.

For 60 years after its discovery in a Ugandan monkey, few humans reported having Zika. Then suddenly in 2016, more than 36,000 cases erupted in Puerto Rico. Although the disease spread throughout the Americas and there were more than 5 thousand cases in the continental U.S, the epidemic was largely confined to U.S. territories, including not only Puerto Rico, but also the U.S. Virgin Islands and American Samoa.^2,3,4

During the Zika epidemic from 2015 to 2017, medical experts were taken aback by the impact the disease had on infants.¹ But they also found that the virus sometimes behaved differently in different regions. For example, the Zika Pregnancy Registry estimated that among infants exposed to Zika during pregnancy in the U.S., only 6 percent developed birth defects. Some researchers suspect that prior exposure to other flaviviruses such as dengue may have worsened its effects outside the U.S.⁵

Viral persistence.

Dr. Paz-Bailey and other researchers have studied the virus in bodily fluids. In their study, about half of the participants had genetic evidence of ZIKV in semen for more than 1 month, in blood for 2 weeks, and in urine for at least 1 week after onset of symptoms. But the virus was mostly undetectable in saliva and vaginal fluids after 1 week.³

Recommendations for prevention.

Results like these reaffirm the CDC's recommendations, which state that:

• Women who are infected or been exposed to ZIKV wait at least 8 weeks from exposure or appearance of symptoms to attempt getting pregnant.
• Men who have possibly been exposed to ZIKV—whether or not they have symptoms—use condoms or abstain from sex for at least 6 months.

Dr. Paz-Bailey's study suggested that ZIKV stays in blood longer than do other flaviviruses such as dengue and West Nile. Therefore, it is also advisable for anyone who may have been exposed to ZIKV to avoid donating blood for at least 4 months.³

Sources

1. CDC: Zika Virus. Available at: https://www.cdc.gov/zika/
2. Rosenberg R et al. MMWR Morb Mortal Wkly Rep. 2018;67(17):496–501. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5933869</https:>
3. Paz-Bailey G. et al. N Engl J Med.2017;doi:10.1056/NEJMoa1613108. Available at https://www.nejm.org/doi/10.1056/NEJMoa1613108?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dwww.ncbi.nlm.nih.gov
4. CDC: Zika Virus. 2016 Case Counts in the US. Available at: https://www.cdc.gov/zika/reporting/2016-case-counts.html
5. Muller WJ and Miller ES. JAMA.2017;317(1):35–36.

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