COVID-19 is a highly communicable disease, but evidence shows that the new closed virus and households are spreading the fastest.
However, there are some settings in which COVID-19 expands more easily. For example, in New York, a search for contacts showed that 70% of new cases come from small gatherings and households.
“Informal gatherings may have played even the biggest role,” Brownstein said, “because they’re harder to carry out by the police, harder to carry out, and people are probably looser when it comes to recommendations on wearing masks and social distancing.”
When people gather in small groups with friends and family, they are more likely to fail, not wear masks, and stay together indoors for longer, making it easier to transmit the virus.
In a recent study at the University of Mississippi Medical Center, researchers found that for children and adolescents who tested positive for COVID-19, small social gatherings – not schools – were the most likely place to be exposed to the virus.
Children who tested positive in the study were more likely to attend social gatherings outside their homes, have play dates or visitors to their home where no precautions were taken to wear masks and social distancing.
At the beginning of the pandemic, after the initial blockades were eased and the cases started to grow, the search for contacts also connected the spread of the virus with restaurants and bars.
In one study published by the Centers for Disease Control and Prevention, people who eventually tested positive for COVID-19 were twice as likely to have eaten at a restaurant in the past two weeks compared to participants who did not test positive for the virus.
“The obvious challenge is to lose important control, wearing a mask,” said Dr. Joseph Allen, assistant professor of exposure assessment science at Harvard TH Chan School of Public Health. “Because you have a restaurant with a lot of people talking loudly [with] it masks itself, leading to higher rates of respiratory aerosol emissions and, depending on how that ventilation system works in the restaurant, determines how many infectious aerosols people breathe. “
Similar to small house gatherings, people in restaurants often eat with people who are not in their immediate household and who do not wear masks, and are indoors with poor ventilation.
“Gyms have generally done a good job of adhering to protocol,” Brownstein said. “We don’t see a lot of super spread of gym-related events … because the protocols they had to establish regarding social removal and wearing masks and ventilation were generally pretty good.”
Schools are another environment in which many people are usually in a closed environment. Educational institutions have grappled with decisions about whether to conduct classroom teaching in relation to distance learning in order to reduce transmission.
But Brownstein said schools are mostly safe. “Of course there is outstanding data,” he added, “but we have seen good evidence that schools have spent time developing protocols in which social distancing and wearing masks have done a relatively good job.”
There are also a lot of guidelines regarding ventilation in schools that make the environment safer, Allen said.
Ultimately, when it comes to what drives high transmission rates in homes and restaurants, it’s a “community of basic factors,” Allen said. “Indoor weather, no masks, poor or no ventilation.”
For weeks, experts have warned of a sharp rise in new infections that will come with Thanksgiving trips. We see that now. The impending rush of travel and small gatherings indoors during the long holiday week between Christmas and New Year cannot come at a worse time, experts warn. However, certain measures can help.
“There’s not a single silver bullet when it comes to interventions. It’s a kind of layered approach,” Brownstein said. “Social distancing and wearing masks … indoor ventilation, restrictions on gatherings … If people adhere to these general public health guidelines in a broader sense, they have been really successful in lowering transmission.”
Adjoa Smalls-Mantey, MD, D.Phil., Is trained in immunology and is a psychiatrist in New York City. He is also an associate at ABC News Medical Unit.