Heat warning and public and workers' health at the time of COVID-19 pandemic

The humanity is currently facing the COVID-19 pandemic challenge, the largest global health emergency after the Second World War. During summer months, many countries in the northern hemisphere will also have to counteract an imminent seasonal phenomenon, the management of extreme heat events. The novelty this year concerns that the world population will have to deal with a new situation that foresees the application of specific measures, including adjunctive personal protective equipment (i.e. facemasks and gloves), in order to reduce the potential transmission of the SARS-CoV-2 virus. These measures should help to decrease the risk of the infection transmission but will also represent an aggravating factor to counteract the heat effects on the population health both at occupational and environmental level. The use of a specific heat health warning system with personalized information based on individual, behavioural and environmental characteristics represents a necessary strategy to help a fast adaptation of the population at a time where the priority is to live avoiding SARS-CoV-2 infection. [Display omitted] •WHO produced guidelines about the use of PPE to reduce the transmission of SARS-CoV-2.•The synergistic effect between heat and anti-COVID-19 measures must be studied.•Researchers must study how PPE behave when used in outdoor warm condition.•A PPE-inclusive customized heat-warning system is useful at the time of COVID-19.•Interventions to review HHWSs in the context of COVID-19 are strongly required.