ICU admissions and in-hospital deaths linked to covid-19 in the Paris region are correlated with previously observed ambient temperature

OBJECTIVE

To study the effect of weather on severity indicators of coronavirus disease 2019 (covid-19).

DESIGN

Ecological study.

SETTING

Paris region.

POPULATION

Severely ill patients with covid-19.

MAIN OUTCOME MEASURES

Daily covid-19-related intensive care unit (ICU) admission and in-hospital deaths in the Paris region, and the daily weather characteristics of Paris midtown.

RESULTS

Daily ICU admissions and in-hospital deaths were strongly and negatively correlated to ambient temperatures, with a time lag. The highest Pearson correlation coefficients and statistically significant P values were found 8 days before occurrence of ICU admissions and 15 days before deaths.

CONCLUSIONS

The study findings show a strong effect of previously observed ambient temperature that has an effect on severity indicators of covid-19.

Strengths and limitations of this study

We assessed the link between weather characteristics with a time lag and covid-19-related hospital severity indicators.

This is the first study, with reliable data, to find a strong negative correlation between previously observed ambient temperature with covid-19-related iCU admissions and in-hospital deaths.

It is compatible with the natural history (including hospitalisation) of covid-19 outbreak in a highly developed country.

We also report the duration after which iCU admissions and in-Hospital deaths occurs following temperature variation (respectively median of 8 and 15 days).

Our analyses are mainly valid for temperate climate countries.