While we know a lot more about the pandemic virus SARS-CoV-2 and the illness it causes, COVID-19, there are still many uncertainties. Though the virus is still spreading in communities in the United States, it seems that stay at home orders have flattened the expected initial spike of hospitalizations and death from the first wave of infection nearly everywhere but the New York City area, which is now recovering from a tough couple of months during which thousands died.
Images from social media and the news are now showing masses of people congregating outdoors, and stay at home orders are lifted or being loosened in most states. So what is the risk of infection?
It's still important to consider your health and age, as well as how prevalent the virus is in your area when assessing risk.
Both NPR and Business Insider spoke to several experts about various activities, and the consensus seems to be that there are several critical factors when evaluating risk: duration, ventilation, and congregation. Meaning: the longer one spends with other potentially infected people, the higher the risk of COVID-19 transmission; the virus is also more likely to be transmitted indoors, especially when the space is not well-ventilated; in addition, the virus will be easier to catch if people are not able or willing to practice social distancing.
Some points to consider: one study has suggested that loud talking produces droplets containing the virus, and that these infectious droplets can linger in the air for eight minutes or more. So if you are going to be inside, is it crowded? Is it well-ventilated? Are the other people there wearing masks? The answers to those questions could have a big impact on risk.
A preprint study has suggested that transmission may be up to 18.7 times more likely in an indoor space. In another report regarding a South Korean call center, 97 employees out of 811 got sick. All but three that were infected worked on the same floor and 79 of them sat in the same section.
"This virus really likes people being indoors in an enclosed space for prolonged periods of close face-to-face contact," William Schaffner, an infectious-disease expert at Vanderbilt University, told Business Insider. "The farther away you are and the shorter duration of contact between you and other people means you get less efficient virus transmission."
Another factor that may play a role is intoxication; if people are drinking they're less likely to be distancing.
While over 1.6 million Americans have been confirmed to have the infection (there are currently around 1.1 million known active cases), we are a long way from herd immunity.
COVID-19 is thought to have an R0 of 3, meaning that every infected person will infect approximately 3 people. In order to achieve herd immunity, over 70 percent of the US population - around 229 million people, would have to be infected with SARS-CoV-2. With a fatality rate estimated at 1 percent, that strategy could also cause over 2 million deaths.
