Study suggests dengue may provide some immunity against COVID-19

Source: Reuters Published: 2020/9/22 19:48:40

A new study that analyzed 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.

A worker sprays pesticide as part of the fight against dengue fever outside the Esplanade arts center in Singapore on May 20. Photo: Xinhua

The not yet published study led by Miguel Nicolelis, a professor at Duke University, and shared exclusively with Reuters, compared the geographic distribution of coronavirus cases with the spread of dengue in 2019-20.

Places with lower coronavirus infection rates and slower case growth were locations that had suffered intense dengue outbreaks in 2019-20, Nicolelis found.

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

"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 the results are particularly interesting because previous studies have shown that people with dengue antibodies in their blood can test falsely 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.

The study was being published ahead of peer review on the MedRxiv preprint server and will be submitted to a scientific journal. It highlights a significant correlation between lower incidence, mortality and growth rate of COVID-19 in populations in Brazil where the levels of antibodies to dengue were higher.

Brazil has the world's third highest total of COVID-19 infections with more than 4.4 million cases - behind only the US 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 in 2019 and early in 2020, 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. 

Nicolelis said his team came across the dengue discovery by accident.
Newspaper headline: Dengue may provide immunity against COVID-19: study


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