How our behavior and participation in indoor activities is behind the Covid-19 outbreaks

24 August 2020 (Last Updated August 24th, 2020 13:51)
How our behavior and participation in indoor activities is behind the Covid-19 outbreaks

There are now more than 5.5 million confirmed cases of COVID-19 in the US. The disease has reached all 50 states, and California, Florida, and Texas are the top three most affected regions. The virus is thought to spread primarily from person to person through respiratory droplets produced when an infected person coughs, sneezes, or talks. These droplets can land in the mouth or nose of a nearby person and then be inhaled into the lungs. Since mid-June and up to early August, the US saw a surge of new COVID-19 cases in several regions as states re-opened. Several outbreaks across the US have been traced back to bars and nightclubs as the source of contagion. This coincides with a growing amount of evidence that points to indoor activities increasing the risk for contracting COVID-19. As lockdown measures were eased in the US, the population returned to their workplaces and other public buildings where they spent increasing amounts of time in inadequately ventilated areas, and new cases of COVID-19 surged. Bars and nightclubs were particular hotspots for transmission because of the characteristics of the SARS-CoV-2 virus that causes COVID-19, and behaviors associated with gatherings in these venues.

A study by van Doremalen and colleagues published in The New England journal of Medicine showed that SARS-CoV-2 could remain alive in airborne particles for more than an hour, increasing the chance that someone could inhale the virus and allowing for viral particles to build up in the air, especially in poorly ventilated areas. Preliminary results from a study in China support the idea that poor ventilation is associated with increased COVID-19 transmission. The study in China analyzed 318 outbreaks in the country and early findings point to 317 of those outbreaks occurring in indoor settings. Similar results have been observed in a study in Japan (which is still under review). In July, physicians at the Texas Medical Association (TMA) created a chart to help the public make informed choices about which activities were the least risky during the COVID-19 pandemic. The chart ranked activities on a scale of one to ten with ten being the riskiest. TMA physicians rated the activities assuming that participants would wear a mask when practical, stay at least six feet away from people who are not immediate family members, and wash their hands frequently. The highest risk came from activities like going to a bar, attending an event with 500 or more people such as a religious service or concert, and going to a movie theater. This is because several of the risk factors for airborne viral transmission come together in these settings. Aside from poor ventilation, risk factors associated with increased risk of COVID-19 are behaviors like singing and speaking loudly, which have been shown to help spread respiratory droplets that contain the virus. For example, people in bar settings tend to take their masks off in order to drink, tend to cluster together, speak loudly, and move around indoors. This means that if a person has the virus, they can spread it more easily and to more people than if they were outdoors and seated at a table. Additionally, when people drink they become more relaxed and less likely to observe social distancing.

There is currently no vaccine to fight the coronavirus disease 2019 (COVID-19), so the best way to lower the risk of transmission is changing our behaviors, so we follow hand hygiene protocols, avoid close contact with other people, and wear a mask to cover our nose and mouth when around others. The numerous outbreaks seen across the US that have been traced back to venues such as bars highlight why SARS-CoV-2 has been labeled a ‘social virus,’ and clearly link our behaviors and choice of venues for social gatherings as drivers of COVID-19 outbreaks.