Impact of sars-cov-2 interventions on dengue transmission.

Jue Tao Lim,Borame Sue Lee Dickens,Alex R Cook,Lawrence Zheng Xiong Chew,Esther Li Wen Choo,Lee Ching Ng,Joel Aik,Joel Ruihan Koo,Isaac Chun-Hai Fung

doi:10.1371/journal.pntd.0008719

Abstract

An estimated 105 million dengue infections occur per year across 120 countries, where traditional vector control is the primary control strategy to reduce contact between mosquito vectors and people. The ongoing sars-cov-2 pandemic has resulted in dramatic reductions in human mobility due to social distancing measures; the effects on vector-borne illnesses are not known. Here we examine the pre and post differences of dengue case counts in Malaysia, Singapore and Thailand, and estimate the effects of social distancing as a treatment effect whilst adjusting for temporal confounders. We found that social distancing is expected to lead to 4.32 additional cases per 100,000 individuals in Thailand per month, which equates to 170 more cases per month in the Bangkok province (95% CI: 100–242) and 2008 cases in the country as a whole (95% CI: 1170–2846). Social distancing policy estimates for Thailand were also found to be robust to model misspecification, and variable addition and omission. Conversely, no significant impact on dengue transmission was found in Singapore or Malaysia. Across country disparities in social distancing policy effects on reported dengue cases are reasoned to be driven by differences in workplace-residence structure, with an increase in transmission risk of arboviruses from social distancing primarily through heightened exposure to vectors in elevated time spent at residences, demonstrating the need to understand the effects of location on dengue transmission risk under novel population mixing conditions such as those under social distancing policies.

Highlights

An estimated 105 million dengue infections occur per year, with case counts reported in over 120 countries [1, 2]
Significant healthcare burdens arise from dengue and traditional vector control is the primary control strategy to reduce dengue transmission potential
The ongoing SARS-CoV-2 pandemic has resulted in dramatic reductions in human mobility due to social distancing measures; the effects on vector-borne illnesses are not known

Summary

Introduction

An estimated 105 million dengue infections occur per year, with case counts reported in over 120 countries [1, 2]. Southeast Asia and the Western Pacific region is estimated to bear 75% of the global burden of dengue [3]. The tropical-subtropical climate of Southeast Asia is suitable [8] for the vector and in conjunction with increasing human population connectivity, population density, global warming and urbanisation within the region, creates an ideal environment for dengue transmission to occur [9,10,11]. Urban centers in Southeast Asia often report the highest number of dengue case counts, which are postulated to seed outbreaks in other localities [9] and increases in temperatures due to climate change allow for optimal vector breeding conditions, shorten the incubation period of the dengue virus and increase the overall risk of dengue disease within the region [12]

Methods

Results

Discussion

Conclusion