Dengue exposure may provide some COVID-19 immunity, researchers say

Exposure to the mosquito-borne illness dengue fever may provide some immunity against COVID-19, Reuters reported Monday, citing a new study. 

The not-yet-published study analyzed the coronavirus outbreak in Brazil and found a link between the spread of the virus and past outbreaks of dengue fever, according to the newswire. 

The study led by Miquel Nicolelis, a professor at Duke University, reportedly compared geographic distribution of coronavirus cases with the spread of dengue in 2019 and 2020. 

Nicolelis found that places with lower coronavirus infection rates and slower case growth were also locations that had suffered intense dengue outbreaks this year or last. 

“This striking finding raises the intriguing possibility of an immunological cross-reactivity between dengue’s Flavivirus serotypes and SARS-CoV-2,” the study reportedly said, referring to dengue virus antibodies and the novel coronavirus.

The researcher told Reuters the results are particularly interesting as previous studies have shown people with dengue antibodies in their blood can test falsely positive for COVID-19 antibodies even if they have not been infected by the coronavirus. 

“This indicates that there is an immunological interaction between two viruses that nobody could have expected, because the two viruses are from completely different families,” Nicolelis said.

He added that further studies are needed to prove the connection.

Brazil has reported the third-highest number of coronavirus cases globally, behind the U.S. and India, respectively, according to data compiled by Johns Hopkins University. It has reported more than 4.5 million cases and 136,895 deaths.