Zika Update: People Infected with Zika VIrus Might be Immune to Reinfection

A new study involving researchers from Kansas State University' Biosecurity Research Institute showed that people who are infected with Zika virus may developed immunity against possible reinfection.

The study, published in the journal Nature Medicine, showed that primary Zika virus infection elicits protective immunity, providing complete protection against other strains derived from the primary Zika virus.

"The research shows that infection provides excellent protection against reinfection," said Stephen Higgs, director of the Biosecurity Research Institute at Kansas State University, in a press release. This means people infected during this current epidemic will likely not be susceptible again. When a large proportion of the population is protected - known as herd immunity - the risk of future epidemics may be low."

For the study, the researchers infected rhesus and cynomolgus macaques with a strain of Zika virus that are highly related to the ones currently circulating in the Americas. The researchers then re-infected the animals 45 days after the primary infection with a heterologous strain. The re-infection of heterologous strain after the primary infection resulted in a complete protections, suggesting that primary Zika virus infection elicits protective immunity.

During the study, the researchers also discovered that Zika RNA can be detected in blood plasma as early as the first day on infection. The researchers were able to detect Zika RNA saliva, urine, cerebrospinal, semen and vaginal secretions.

Within 10 days of infection, the blood plasma and urine were cleared of Zika RNA. However, the viral RNA can still be detected in the saliva and seminal fluids at least three weeks after the Zika RNA was cleared from the blood.

Furthermore, the researchers were able to identify ZIKA RNA in some tissues, including brain and the reproductive organs of both male and female animals during the early and late stages of the viral infection.

At present, Centers for Disease Control and Prevention received about 3,936 cases of Zika Infection in the United States and 25,955 cases in the US territories.