The impacts of COVID-19 mitigation on dengue virus transmission: a modelling study

Abstract

SummaryBackgroundThe COVID-19 pandemic has induced unprecedented reductions in human mobility and social contacts throughout the world. Because dengue virus (DENV) transmission is strongly driven by human mobility, behavioral changes associated with the pandemic have been hypothesized to impact dengue incidence. By discouraging human contact, COVID-19 control measures have also disrupted dengue vector control interventions, the most effective of which require entry into homes.MethodWe used an agent-based model with a realistic treatment of human mobility and vector control to investigate how and why dengue incidence could differ under a lockdown scenario with a proportion of the population sheltered at home.ResultWe found that a lockdown in which 70% of the population sheltered at home led to a small average increase in cumulative DENV infections of up to 10%, depending on the time of year lockdown occurred. Lockdown had a more pronounced effect on the spatial distribution of DENV infections, with higher incidence under lockdown in regions with high mosquito abundance. Transmission was also more focused in homes following lockdown. The proportion of people infected in their own home rose from 54% under normal conditions to 66% under lockdown, and the household secondary attack rate rose from 0.109 to 0.128, a 17% increase. When we considered that lockdown measures could disrupt regular, city-wide vector control campaigns, the increase in incidence was more pronounced than with lockdown alone, especially if lockdown occurred at the optimal time for vector control.DiscussionOur results indicate that an unintended outcome of COVID-19 control measures may be to adversely alter the epidemiology of dengue. This observation has important implications for an improved understanding of dengue epidemiology and effective application of dengue vector control. When coordinating public health responses during a syndemic, it is important to monitor multiple infections and understand that an intervention against one disease may exacerbate another.

Shifts in outdoor activity patterns in the time of COVID-19 and its implications for exposure to vector-borne diseases in the United States.

“…Nonetheless, the group-level shift towards peridomestic activities and increased tick exposure indicates either an increase in the overall tick population or increased exposure in those settings where participants are less inclined to use preventative measures against tick bites 30 . A similar pattern was observed for mosquito-borne disease in two studies on dengue infection: i) a simulation model found that COVID-19 stay-at-home measures (in which 70% of the population restricted their mobility to their house) led to an increase in overall infections and increased clustering of cases at the household level 42 ; and b) an empirical study using dengue case report data in Singapur found a 37.2% increase in the number of cases from expected baseline levels attributed to COVID-19 stay-at-home measures 43 .…”