Cross-reactivity between dengue virus and SARS-CoV-2 antibodies: Confirmation study using specimens from dengue-infected patients before the COVID-19 pandemic

Few (6.7 %) of the pre-COVID-19 dengue Ab-positive serum samples showed reactive on SARS-CoV-2 in the RDT, with significantly lower IgG and IgM levels detected in ELISA compared with the dengue samples collected during the pandemic and the COVID-19 samples (<i>P</i> < 0.005). A comparable anti-SARS-CoV-2 IgG concentration was observed in the pre-COVID-19 dengue samples and healthy volunteers (<i>P</i> = 0.56), which also indicated other possibilities. In conclusion, our results suggested a low risk of cross-reactivity between dengue virus and SARS-CoV-2. However, they highlighted the need for caution when using and interpreting data obtained stemming from serological methods, to prevent false-positive results. Further studies are needed to evaluate the cross-reactivity between dengue virus, SARS-CoV-2, and other common human pathogens, as well as its effect on the serosurveys, treatment of these diseases, or vaccine efficacy.