Low dengue incidence in 2020 was attributable to COVID-19-related disruption, according to a study published in The Lancet Infectious Diseases. Oliver Brady, DPhil, and colleagues collected data on monthly dengue incidence from WHO reports, climatic data, and population variables for 23 countries between January 2014 and December 2019 to predict seasonal and multi-year dengue cycles. Predictions were compared with reported dengue data from January-December 2020. Across many dengue endemic regions, a consistent, prolonged decline in dengue incidence occurred beginning in March 2020 (2.28 million cases in 2020 vs 4.08 million in 2019). A strong association was observed for COVID-19-related disruption and reduced dengue risk, even after accounting for other drivers of dengue cycles (relative risk, 0.01-0.17). The strongest evidence was seen for measures related to school closures and less time in non-residential areas; however, there was high collinearity between covariables. In 2020, an estimated 0.72 million fewer dengue cases occurred that were potentially attributable to COVID-19-related disruption.
