  Background: Studies have shown that human mobility is an important factor in
dengue epidemiology. Changes in mobility resulting from COVID-19 pandemic set
up a real-life situation to test this hypothesis. Our objective was to evaluate
the effect of reduced mobility due to this pandemic in the occurrence of dengue
in the state of S\~ao Paulo, Brazil. Method: It is an ecological study of time
series, developed between January and August 2020. We use the number of
confirmed dengue cases and residential mobility, on a daily basis, from
secondary information sources. Mobility was represented by the daily percentage
variation of residential population isolation, obtained from the Google
database. We modeled the relationship between dengue occurrence and social
distancing by negative binomial regression, adjusted for seasonality. We
represent the social distancing dichotomously (isolation versus no isolation)
and consider lag for isolation from the dates of occurrence of dengue. Results:
The risk of dengue decreased around 9.1% (95% CI: 14.2 to 3.7) in the presence
of isolation, considering a delay of 20 days between the degree of isolation
and the dengue first symptoms. Conclusions: We have shown that mobility can
play an important role in the epidemiology of dengue and should be considered
in surveillance and control activities
