London School of Hygiene & Tropical Medicine

Professor Laura Rodrigues has provided expert comment on the results of a study that estimates that the risk of microcephaly is about one for every 100 women infected with Zika virus during the first trimester of pregnancy.

The new research, published in The Lancet, is based on data from the 2013-14 Zika outbreak in French Polynesia, and further supports the association between Zika virus and microcephaly. The authors say that quantifying the risk may help better inform the broader public health response.

Although evidence of the association between microcephaly and Zika virus is growing, the risk has so far not been quantified. The authors say that the association remains an important public health issue because the risk of Zika virus infection is particularly high during outbreaks, such as the current one in South America.

Writing in a linked Comment piece in The Lancet Laura Rodrigues, Professor of Infectious Disease Epidemiology at the School, said: "The finding that the highest risk of microcephaly was associated with infection in the first trimester of pregnancy is biologically plausible, given the timing of brain development and the type and severity of the neurological abnormalities," but highlights that more research is needed: "Further data will soon be available from Pernambuco, Colombia, Rio de Janeiro, and maybe other sites.

"The fast production of knowledge during this epidemic is an opportunity to observe science in the making: from formulation of new hypotheses and production of new results that will provide confirmations and contradictions to the refinement of methods and the gradual building of consensus."

Publication

• Laura Rodrigues. Microcephaly and Zika virus infection. The Lancet. DOI: 10.1016/S0140-6736(16)00742-X

Related links

• Zika Q&A with Laura Rodrigues
• Zika virus outbreak and related research