Previous exposure to dengue may provide some immunity against COVID-19

Researchers found lower incidence, mortality and growth rate of COVID-19 in populations in Brazil where the levels of antibodies to dengue were higher.

By: Longjam Dineshwori | | Updated: September 23, 2020 9:25 am

The study indicated the possibility of an immunological interaction between dengue virus and the novel coronavirus. @Shutterstock

If you have had a dengue virus infection in the past, you may have some protection against COVID-19. This is what a yet to be published study has suggested. Also Read - COVID-19: New tool can help decontaminate viruses in aerosols. Know more about it

The study, which was shared exclusively with Reuters, found a link between the spread of the coronavirus in Brazil and past outbreaks of dengue fever. Led by Miguel Nicolelis, a professor at Duke University, the research team compared the geographic distribution of coronavirus cases in the country with the spread of dengue in 2019 and 2020. Also Read - Schizophrenia emerges as the second highest risk factor of COVID-19 mortality

Surprisingly, coronavirus infection rates were found to be slower and lower in places that had suffered intense dengue outbreaks last year and early this year. It also found lower COVID-19 mortality rates in populations where the levels of antibodies to dengue were higher. Also Read - Don’t expect to get rid of coronavirus by 2021: WHO warns of continued Covid-19 transmission

Not just in Brazil, the team also 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.

Based on this finding, the research team suggested that past exposure to the dengue virus may provide some level of immunity against the novel coronavirus. It also raises the possibility of immunological cross-reactivity between dengue’s Flavivirus serotypes (dengue antibodies) and SARS-CoV-2, the virus that causes COVID-19.

Can the dengue vaccine protect against the novel coronavirus?

The dengue vaccine Denvaxia (CYD-TDV) is licensed and available in some countries for people ages 9-45 years old. However, the World Health Organization recommends that the vaccine should be only given to persons with confirmed prior dengue virus infection. Sanofi Pasteur, the manufacturer of the vaccine, had also cautioned that people who have not been previously infected with a dengue virus may be at risk of developing severe dengue if they get the mosquito-transmitted illness after being vaccinated. Can this dengue vaccine be used to prevent coronavirus infection?

Although the dengue virus and SARS-CoV-2 are from completely different families, the Duke University study indicated the possibility of an immunological interaction between two viruses.

“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,” Reuters quoted the study as saying.

Previous studies have also suggested 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, Nicolelis told Reuters as he stressed that need for further studies to prove the connection.

COVID-19 and dengue fever: How to tell them apart

Dengue and COVID-19 share some common symptoms such as fever, cough, and sore throat. But these two diseases are different in many ways. Here are some points that may help you tell them apart.

Dengue is a mosquito-borne viral infection that is transmitted to humans through the bites of infected female mosquitoes. Usually, dengue symptoms develop four to six days after infection and last for up to 10 days. If you have dengue, you may experience a sudden high fever (40°C/104°F) accompanied by two of the following symptoms:

Severe headache
Pain behind the eyes
Severe joint and muscle pain
Fatigue
Nausea
Vomiting
Skin rash, which appears two to five days after the onset of fever
Mild bleeding (such a nose bleeding, bleeding gums, or easy bruising)
Swollen glands

COVID-19 is a contagious disease caused by the most recently discovered coronavirus, SARS-CoV-2. The virus is spread from person to person through respiratory droplets.

The most common symptoms of COVID-19 are fever, tiredness, and dry cough. Other less common symptoms include aches and pains, nasal congestion, runny nose, sore throat or diarrhea. In serious cases, one may develop difficulty breathing, and pneumonia.

Published : September 22, 2020 1:07 pm | Updated:September 23, 2020 9:25 am

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