A new study that analysed the coronavirus outbreak in Brazil has found a link between the spread of the virus and past outbreaks of dengue fever that suggests exposure to the mosquito-transmitted illness may provide some level of immunity against COVID-19.
The study, which has not yet been published was led by Miguel Nicolelis, a professor at Duke University, compared the geographic distribution of coronavirus cases with the spread of dengue in 2019 and 2020.
Places with lower coronavirus infection rates and slower case growth were locations that had suffered intense dengue outbreaks this year or last, Nicolelis found.
“If proven correct, this hypothesis could mean that dengue infection or immunization with an efficacious and safe dengue vaccine could produce some level of immunological protection” against the coronavirus, it added.
Nicolelis told Reuters that the reveal was interesting because previous studies have shown that people with dengue antibodies in their blood can falsely test positive for COVID-19 antibodies even if they have never 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, adding that further studies are needed to prove the connection.
Brazil has the third-highest total of COVID-19 infections in the world with more than 4.4 million cases – behind only the United States and India. In states such as Paraná, Santa Catarina, Rio Grande do Sul, Mato Grosso do Sul and Minas Gerais, with a high incidence of dengue last year and early this year, COVID-19 took much longer to reach a level of high community transmission compared to states such as Amapá, Maranhão and Pará that had fewer dengue cases.
The team found a similar relationship between dengue outbreaks and a slower spread of COVID-19 in other parts of Latin America, as well as Asia and islands in the Pacific and Indian Oceans.