The fact that poor ventilation and aerosols play a decisive role in the spread of the coronavirus was suspected shortly after the first major outbreak in early February 2020 at a carnival event in the Heinsberg district. The connection was later proven in many studies. Now the Bonn virologist Hendrik Streeck and other scientists are presenting exact findings for the course of the first outbreak in a study published as a preprint. The researchers were able to interview a total of 411 people between the ages of six and 79 years of the 450 participants in the cap meeting in the small village of Gangelt, 46 percent of whom were infected with the virus.

The ventilation system in the event hall - the windows of which were closed - only supplied 30 percent fresh air.

Participants in the carnival session had an increased risk of infection if they were seated near the table where the air was being sucked in or if they were standing at the bar where the air was being fed in.

The scientists did not find any confirmation for the research thesis that alcohol consumption could have increased the risk of infection at the carnival session.

Initially, it was speculated that participants who had drunk a lot were more disinhibited and sought more physical closeness.

Notably, smokers had a reduced risk of infection at the Gangelter cap session. According to the study, this can be attributed to the fact that the smokers often went outside the hall and inhaled fresh air. Age was confirmed to be a major risk factor. According to this, the risk of infection increased by 28 percent per decade of life during the cap session up to the age of 40.