The government should not relax the implementation of social distancing interventions in warm seasons/areas, says a study published in “Science of the Total Environment”. Researchers undertook this analysis to explore the modifying effects of ambient temperature on the link between social distancing and SARS-CoV-2 transmission.

In this observational time-series study, an interrupted time-series model was utilized with a state-level random intercept for analyzing data. To investigate their interactions, an interaction term of ‘physical distancing×temperature’ was incorporated. In order to assess the modifying effects, the stratified analyses by temperature and social distancing implementation were also carried out.

The overall median (interquartile range) reproductive number of SARS-CoV-2 was 1.2 (1.0–2.3). Implementing physical distancing was linked with a 12% decline in the risk of reproductive number (relative risk [RR]: 0.88), and each 5°C rise in temperature was related to a 2% decline (RR: 0.98). A substantial interaction was noted between ambient temperature and social distancing on the spread of coronavirus. However, all the RRs were small.

The containing effects of elevated temperature were attenuated by 5.1% when there was an implementation of physical distancing. The link of COVID-19 effective reproductive number with social distancing implementation was more stable (0.89 vs. 0.88 in days when the temperature was high and low, respectively).

A raised temperature in warm seasons/areas was not found to offset the containing effects of social distancing on coronavirus transmission. Both raised ambient temperature and implementing physical distancing interventions were linked with a minimized risk of coronavirus transmission. This transmission was found to be much more strongly related to physical distancing implementation in comparison with ambient temperature.

A certainty solely on raised temperature to contain coronavirus transmission is not sufficient. Implementing social distancing might play a more essential role in the containment of SARS-CoV-2, at least during the early stage of this deadly outbreak, concluded the study authors.