In response to the Zika epidemic, the National Institutes for Health (NIH) has launched a study to shed light on how coinfection with HIV and Zika impact maternal and fetal health. Although the study is currently designed to follow infants for only one year, if all goes well, the NIH may try to build longer-term relationships with families to gauge developmental impacts on children later in life.
Among women with HIV, modern antiretroviral treatment can help prevent mother-to-child transmission. However, moms with a secondary infection, such as syphilis, herpes or hepatitis, carry a greater risk of passing HIV to their children.
When it comes to the Zika virus, there are a lot of unanswered questions, Catherine Y. Spong, M.D., deputy director of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), told TheBody.com. Does Zika infection interfere with HIV medication? Conversely, could an existing HIV infection make Zika more dangerous? How do these factors impact the health of a newborn child?
"Given that pregnancy itself is an immunocompromised state," Spong and her colleagues wondered "how a Zika infection might impact outcomes among women with HIV."
Like malaria, Zika is spread by mosquitos. In most people, it causes minor to no symptoms, but an infection during pregnancy can lead to serious developmental defects. Although the Zika virus was identified decades ago, it gained global attention when an epidemic broke out in Brazil in 2015 and an unusual number of infants were born with microcephaly.
The NIH's study will enroll four groups of pregnant women: those with HIV, those with Zika, those with both HIV and Zika and those with neither virus. Patients will be recruited from centers in Puerto Rico, Brazil and U.S. states that have been affected by the Zika virus, such as Florida and Texas. The study, which is sponsored by the NIH's NICHD, will be conducted in two parts.
Initially, researchers will try to recruit 200 pregnant women for the study. If recruitment goes well, they will then try to enroll an additional 1,800 women, for a total of 2,000 by the end of the study. Overall, this will probably take four to six years, with results expected after that.
Although the results are a long way off, Spong said it's important to start this research now, as Zika may continue to spread across the globe. For example, a recent outbreak in Singapore suggests that the virus may spring up easily in places where its close cousin, dengue fever, is endemic. According to the World Health Organization, 84 countries have reported evidence of Zika transmission, and 31 countries have reported microcephaly or another central nervous system malformation associated with Zika.
Public health officials worry that Zika will explode in countries that are not prepared to handle such an outbreak -- especially countries in Africa that already suffer from a high rate of HIV.
"Given that it's certainly possible for Zika infection rates to increase in parts of the world where HIV is widespread, by doing this study, we hope to identify information that helps us best prepare to care for patients who are are co-infected," said Spong.
During the study, women will be monitored during pregnancy and for six months after birth, and their children will be monitored for one year. Unfortunately, new evidence has come to light that Zika-related defects may not always be obvious soon after birth. Recently, some Zika-infected mothers have given birth to children who seemed healthy at birth, but developmental complications emerged six to nine months later.
"Unfortunately, we don't have a lot of information about the long-term impact of Zika" on children, said Spong. "Recent information suggests that the impact may not be known even at a year."
Therefore, although the study was designed to follow children for one year after birth, Spong said, "It's not our desire to end at a year." Study coordinators may ask some mothers whether they would be willing to check in after the one-year mark.
"When you're trying to design a study, you want to be reasonable," Spong added, which is why the study was designed with a one-year cut off. However, she said, "We anticipate talking with these families for longer."
Although it's too soon to know how conifection with HIV and Zika might impact pregnant women and their children, the NIH's study is an important first step.
"I think this is a study that's going to be able to provide us with information, so women in the future will be able to have concrete [understanding] of the risks," said Spong.