Zika Outbreak Could Last 3 Years, Scientists Estimate

The Zika virus outbreak spreading through the Americas could go on for three years, according to a new study published in the journal Science.

Scientists from Imperial College London and Johns Hopkins Bloomberg School of Public Health estimate that the current Zika epidemic will be “largely over” in Latin America in three years. That’s because so many people are being infected, and therefore become immune to the virus. “Herd immunity will likely then cause a delay of over a decade until further large epidemics are possible,” they write in the study.

The Zika virus is confirmed to cause the severe birth defect microcephaly, and it’s estimated millions of people are infected in the Americas. In the continental U.S. there are over 1,000 people infected due to travel, including 320 pregnant women. There are also 2,534 people in U.S. territories who are infected, including 279 pregnant women. On Wednesday it was reported that the first baby in Texas with Zika-related microcephaly was born. The U.S. Congress on Thursday failed to pass the $1.9 billion in funding to fight Zika that was requested by the White House in February.

The researchers note that some countries where the virus is spreading have advised people to avoid pregnancy, which the study authors write “has been criticized for being infeasible for many women—especially long term.” Understanding a country’s local context through monitoring could be helpful, they suggest. Mosquito control can also help prevent some spread, but the authors argue that expectations should be realistic, and that traditional insecticide use has not necessarily prevented other serious mosquito-borne diseases like dengue from spreading in the past.

“Like Ebola, Zika is a public health crisis in which policymakers have had to make decisions in the presence of enormous uncertainty,” the study authors conclude. “The current epidemic is not containable; at best, interventions can mitigate its health impacts. More optimistically, the natural dynamics of the epidemic are now likely to give a multiyear window to develop new interventions before further large-scale outbreaks occur.”