The outbreak of the Covid-19 pandemic may have led to a more severe clinical course in dengue cases, an important study undertaken by Indian scientists at the government-run Translational Health Science and Technology Institute (THSTI) has found.
The study, which is yet to be peer-reviewed, found that Covid antibodies can cross-react with the dengue virus serotype, potentially enhancing dengue infection.
Dengue, a vector-borne disease that is endemic in the country, has surged by more than 1,312% since the initial significant outbreak in 1996. Data from the National Centre for Vector Borne Diseases Control (NCVBDC) shows that in 2022, 303 dengue patients lost their lives.
The occurrence of dengue haemorrhagic fever and dengue shock syndrome remains a significant contributor to fatalities.
According to the analysis by 24 authors of THSTI – an autonomous institute under the Department of Biotechnology, Ministry of Science and Technology – antibodies against SARS-CoV-2 displayed cross-reactivity with DENV-2, a dengue-causing virus serotype.
They also found that these antibodies, whether obtained from natural human infection or experimental animal immunisation, had the capacity to boost dengue infection in animal cells.
This preprint study is the first to provide evidence that antibodies against SARS-CoV-2 can cross-react with a dengue virus serotype and increase its infection via antibody-dependent enhancement.
According to a top government scientist, who did not wish to be named, over the last few decades, there has been significant evolution in the dengue virus in India, as it undergoes changes and adapts to various selective forces, potentially resulting in the emergence of new variants.
Before 2012, the prevalent strains of dengue in India were primarily DENV 1 and 3. However, in recent times, DENV 2 has gained dominance throughout the country, and even DENV 4, formerly considered less infectious, is now establishing a presence in South India.
Study Prompted by Latest Surge in Cases
The pathogenesis of dengue disease, which is highly prevalent in tropical and subtropical regions worldwide, is still incompletely understood, particularly in comparison to other endemic viruses. This makes dengue a deadly disease.
Pathogenesis is the process by which a disease develops and progresses in an organism. The authors conducted this study with the objective of exploring the impact of Covid-19, given the latest surge in dengue cases.
“Antibodies against SARS-CoV-2 (RBD and Spike) showed significant cross-reactivity with DENV-2 (E protein),” said the study which has been published at bioRxiv, the preprint server for medical sciences.
“Also, anti-SARS-CoV-2-commercial antibodies, immunised animal sera and 46 human convalescent plasma samples (from different waves of a pandemic) demonstrated antibody-dependent enhancement (ADE) of DENV-2 infection.”
How the Study Was Conducted
The research done via computer simulations and in-laboratory research confirmed a robust bond between SARS-CoV-2 antibodies and dengue virus, revealing the first instance of cross-reactivity and antibody-dependent enhancement (ADE) between the two.
The study said that human convalescent plasma samples collected during different waves of Covid-19 and monoclonal and polyclonal antibodies raised against SARS-CoV-2 were examined.
The study found that anti-SARS-CoV-2 antibodies had the potential to enhance DENV-2 infection in K562 and U937 cells.
“In-silico and in-vitro studies indicated a strong interaction between SARS-CoV-2 antibodies and DENV-2 E-protein, providing a molecular basis for these findings,” it said. “This study is the first to demonstrate that anti-SARS-CoV-2 antibodies can cross-react with DENV-2 and can enhance its infection through ADE. These findings have implications for SARS-CoV-2 vaccine development and deployment strategies in regions where dengue is endemic.”
