The National Institutes of Health (NIH) and Fundacao Oswaldo Cruz (the Oswaldo Cruz Foundation, also known as Fiocruz), a scientific research organization based in Rio de Janeiro, have begun a study to evaluate the magnitude of health risks that Zika virus infection poses to pregnant women and their developing fetuses, as well as infants. The study will begin in Puerto Rico and expand to several locations in Brazil, Colombia, and other areas experiencing active local transmission of the virus.
The Zika virus is spread primarily through bites from infected Aedes aegypti mosquitoes, although other forms of transmission — notably, mother-to-child and sexual transmission — also occur. The virus is actively being transmitted in 60 countries and territories.
Zika has been linked to a spike in cases of microcephaly, a condition in which babies are born with abnormally small heads and possible neurological damage, sparking international concern. Other problems have also been detected in pregnancies, and among fetuses and infants infected with Zika before birth, including miscarriage, stillbirth, absent or poorly developed brain structures, eye defects, hearing deficits, and impaired growth.
The Zika in Infants and Pregnancy (ZIP) study aims to enroll as many as 10,000 pregnant women, ages 15 and older, at 15 locations. The participants, who must be in their first trimester of pregnancy when joining, will be followed throughout their pregnancies to determine if they become infected with the virus and, if so, what outcomes result for both mother and child. The infants will be carefully followed for at least one year after birth.
“A mother’s environment may be an important part of the Zika virus puzzle,” said NIEHS and National Toxicology Program Director Linda Birnbaum, Ph.D. “We’ve included environmental measures in the study and will also be evaluating nutrition and socio-economic status.”
NIEHS, the National Institute of Allergy and Infectious Diseases (NIAID), and the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) are funding and conducting the study, along with Fiocruz.
“The full scope of the effect of Zika virus in pregnancy has not yet been fully determined,” said NIAID Director Anthony Fauci, M.D. “This large, prospective study promises to provide important new data that will help guide the medical and public health responses to the Zika virus epidemic.”
The researchers plan to compare birth outcomes between mothers who were infected with the Zika virus and those who were not. They will document the frequency of miscarriage, preterm birth, microcephaly, malformations of the nervous system, and other complications. The researchers will also compare the risk of pregnancy complications among women who are infected with the Zika virus and have no symptoms, with those who do.
Additionally, the study will evaluate how the timing of infection affects pregnancy outcomes, and the role environmental influences, social determinants, and other infections, such as dengue virus, play in the health of the study participants and their newborns.
Data to inform prevention and treatment strategies
“Zika virus has spread rapidly through the Americas,” said NICHD Acting Director Catherine Spong, M.D. “We anticipate that this study will provide important information on the link between Zika infection and pregnancy complications, and inform strategies to help safeguard the health of mothers and their newborns.”
“This study, in partnership with NIH, is essential to elucidating the scientific complexity of the Zika virus,” said Fiocruz President Paulo Gadelha. “It will be fundamental to developing prevention and treatment strategies against the disease.”
The ZIP study is distinct from, and complementary to, public health registries underway in the U.S., Puerto Rico, and Colombia, including the U.S. Zika Pregnancy Registry, Zika Active Pregnancy Surveillance System, and SIVIGILA/Projecto Vez. These registries are population-based and collect observations from medical evaluations and testing, with the intent of providing information for public health action.
(This story is based on the June 21 NIH press release.)