Association between climate change and the occurrence of microcephaly due to congenital Zika virus syndrome from 2015 to 2019 in São Luís, Maranhão, Brazil.

The number of cases of microcephaly in live-born babies whose mothers were infected with the Zika virus during pregnancy has increased, especially in the northeastern region of Brazil. The objective is to investigate the association between climate change and the occurrence of microcephaly due to Zika virus infection in the city of São Luís, State of Maranhão, from 2015 to 2019. Secondary information was obtained from the Superintendence of Epidemiological Surveillance of the Maranhão State Health Department and climate data from the National Institute of Meteorology - INMET from 2015 to 2019. The average precipitation of >100 mm per month was considered rainy months, and the number of children born with microcephaly during the first trimester of pregnancy was analyzed, comparing those occurring during the rainy season with those corresponding to the non-rainy season. Between 2015 and 2019, n=59 cases of microcephaly due to the Zika virus were reported and confirmed, of which n=43 (72.88%) pregnancies occurred during the rainy season and n=16 (27.11%) pregnancies during the non-rainy season, with a significant difference between the groups p=0.02 (Student t-test). A positive association was observed between climate change and the occurrence of microcephaly due to Zika virus infection.