Background While Aedes mosquitoes, the Dengue vectors, were expected to expand their spread due to international travel and climate change, the effects of human mobility and low rainfall conditions on them are largely unknown. We aimed to assess these influences during the COVID-19 pandemic in Hong Kong, characterized by varying levels of human mobility. Methods Google′s human mobility indices (including residential, parks and workplaces) and weather conditions (total rainfall and mean temperature) together with Aedes albopictus abundance and extensiveness monitored using Gravidtrap were obtained between April 2020 and August 2022. Distributed lag non-linear models with mixed-effects models were used to explore their influence in three areas in Hong Kong. Findings The relative risk (RR) of mosquito abundance was associated with low rainfall (<50 mm) after 4.5 months, with a maximum of 1.73, compared with 300 mm. Heavy rainfall (>500 mm) within 3 months was also associated with a peak of RR at 1.41. Warm conditions (21-30 ° C; compared with 20 ° C) were associated with a higher RR of 1.47 after half a month. Residential mobility was negatively associated with mosquito abundance. The model projected that if residential mobility in the year 2022 was reduced to the level before the COVID-19 pandemic, the mosquito abundance would increase by an average of 80.49% compared to the actual observation. Significance Both the human mobility and the lag effect of meteorological factors can be critical for the prediction of vector dynamics, and stay-at-home policy may be useful for its control in certain regions.

The authors have declared no competing interest.

We thank Ming Wai Lee from the Food and Environmental Hygiene Department, the Government of HKSAR. The authors gratefully acknowledge support from grants funded by the Health and Medical Research Fund [#2019095], City University of Hong Kong [#7005311, #7005523 and #9610416] and the Research Grants Council (RGC) of Hong Kong under the General Research Fund [#11104620, #11102421, and #11101422].

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