Zika Risks Continue in March 2025

Although the number of Zika virus disease (ZVD) cases has declined globally since 2017, new outbreaks continue to be reported throughout the Americas, including in Puerto Rico.

As of early March 18, 2025, over 3,065 Zika cases have been reported in the Region of the Americas this year.

Last year, 42,127 ZIka cases and two related fatalities were confirmed in the Americas, with the highest proportion of cases reported in South America in Argentina, Brazil, Bolivia, and Colombia.

In the United States, the Puerto Rico Department of Health reported 16 locally acquired Zika cases, primarily in the San Juan district, in 2024.

In 2023, 43 Zika virus cases were reported in Puerto Rico.

While most people recover from ZVD, infections have caused microcephaly, Guillain-Barré syndrome, and other central nervous system malformations.

Furthermore, infants born to Zika-infected mothers have been confirmed to suffer from a greater risk for neurodevelopmental delay and life-long health challenges.

Two recent studies highlight these risks.

A population-based study of mortality rates among children younger than five years old in Brazil published by the JAMA Network in January 2025 shows that children with congenital Zika syndrome had a 13-fold higher risk of death compared with those without the mosquito-transmitted virus.

Additionally, a review published on March 6, 2025, focuses on new insights regarding ZVD in the last two years and summarizes the key literature on global epidemiology, transmission, diagnostics, clinical features, preventive measures, and treatment options.

From a prevention perspective, multiple Zika vaccine candidates are in different stages of clinical development; however, as of March 18, 2025, none have been approved by the U.S. FDA.

The U.S. CDC, the United Kingdom, and Canada say that, without the availability of a preventive vaccine, pregnant women should not travel to areas reporting active Zika outbreaks.

Note: This news article was updated for grammar and data clarifications on March 19, 2025.