A new study looking at the coronavirus outbreak in Brazil found a link between the spread of the virus and past outbreaks of dengue that suggests that exposure to mosquito-borne disease may provide some level of immunity against Covid-19. The yet-unpublished study led by Miguel Nicolelis, a professor at Duke University, and shared exclusively with Reuters, compared the geographic distribution of coronavirus cases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 and 2020.
The places with the lowest rates of coronavirus infection and slower case growth were places that had experienced severe outbreaks of dengue this year or the past, Nicolelis found. “This surprising finding raises the intriguing possibility of an immunological cross-reactivity between dengue flavivirus serotypes and SARS-CoV-2,” said the study, referring to antibodies against dengue virus and novel coronavirus. “If proven to be correct, this hypothesis could mean that dengue infection or immunization with an effective and safe dengue vaccine could produce some level of immune protection” against the coronavirus, he added.
Nicolelis told Reuters that the results are particularly interesting because previous studies have shown that people with dengue antibodies in their blood can test false positive for Covid-19 antibodies even if they have never been infected with 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 more studies are needed to prove the connection. The study was published prior to peer review on the MedRxiv prepress server and will be submitted to a scientific journal.
There is a significant correlation between the lower incidence, mortality and growth rate of Covid-19 in Brazilian populations where the levels of antibodies against 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 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 like 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 in Asia and islands in the Pacific and Indian Oceans. Nicolelis said her team came across the discovery of dengue by accident, during a study focused on how Covid-19 had spread through Brazil, in which they found that roads played an important role in the distribution of cases across the country. . After identifying certain case-free spots on the map, the team searched for possible explanations. A breakthrough came when the team compared the spread of dengue to that of the coronavirus. “It was a shock. It was a total accident, ”Nicolelis said. “In science, that happens, you are shooting at something and you hit a target that you never imagined you would hit.”
(This story was posted from a cable agency feed with no text changes. Only the title was changed.)
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