November 18, 2016, the World Health Organization (WHO) announced that the agency was changing the status of Zika from a “Public Health Emergency of International Concern” to an ongoing, seasonal disease threat. The Zika virus, originally discovered in 1947, was historically considered a mild disease and mostly harmless as about 80 percent of people who are infected show no symptoms. Many infected with Zika also appear able to fight the disease off on their own.
The original WHO emergency was instituted in February 2016 in response to increasing Zika caseloads in Brazil with concurrent cases of microcephaly birth defects in newborns. The change in WHO status for Zika is due, in part, to the much lower rate of infections, death and deformities attributed to the Zika versus what was originally projected after the health emergency was declared.
While Zika still remains problematic in areas which have not yet been infected, public health experts point out that when a large portion of a population has been infected with a virus and has recovered, rising “herd immunity” usually ends the transmission of the virus for several years, until enough susceptible victims are born. Significant progress has also been made in the development of a Zika vaccine, now anticipated to be available as soon as 2018. With more than a dozen companies as well as the National Institutes of Health (NIH) vying for the prize of a successful vaccine, the race is on to bring a vaccine to market. An experimental DNA-based vaccine from NIH is already being tested in clinical trials with volunteers.
While recent Peru cases have increased in Iquitos leading to a city-wide fumigation eradication campaign by local authorities, the Peru Ministry of Health recently reported that Iquitos is the only Peruvian city in which cases continue to be detected in Peru in the last thirteen weeks. Other countries in South America continue to report decreasing numbers of Zika cases.
For more information about Zika including prevention tips, please visit our Zika virus hotsheet.