- Airborne transmission of the virus may be facilitated by certain activities, including speaking, yelling, and singing.
- Compared with breathing alone, those vocalizations produce more aerosolized saliva.
- Some studies have found that certain people emit more droplets of saliva than average when they breathe or speak.
All data and statistics are based on publicly available data at the time of publication. Some information may be out of date.
As states across the country begin to ease COVID-19 restrictions, experts warn that caution is needed to prevent so-called “super spreader” events.
A COVID-19 super spreader event occurs when someone who’s carrying SARS-CoV-2 passes the virus to multiple people at an event or gathering.
In Chicago, Illinois,
“If there’s a minimally symptomatic or even asymptomatic super spreader at one of these types of gatherings, this virus will be spread to other people,” Dr. Joseph Khabbaza, a pulmonology and critical care specialist at Cleveland Clinic’s Independence Family Health Center in Independence, Ohio, told Healthline.
“Whether they develop symptoms or not, they are then able to spread the virus to other more vulnerable people in their lives such as parents, grandparents, or any high risk population,” he continued.
SARS-CoV-2 seems more likely to spread under certain conditions, according to Khabbaza.
For example, events or gatherings that take place inside appear to pose greater risk than outdoor events.
Gatherings where people sit or stand close together also appear to be more dangerous than those where people maintain their distance from each other, he said.
Airborne transmission of the virus may also be facilitated by certain activities, including speaking, yelling, and singing. Compared with breathing alone, those vocalizations produce more aerosolized saliva.
That may help account for the large number of cases linked to the choir practice in Washington, as well as a cluster of cases traced to nightclubs in Seoul, South Korea.
“The choir and nightclub are both settings where I think more droplets are produced, either from singing or having to speak loudly over music around you,” Khabbaza said, “and then you also have people in close proximity.”
Additionally, it’s possible that people can contract the virus if they touch the same surfaces or items, such as shared serving ware at a potluck. If a person with the virus touches an item, it enables the virus to be passed between surfaces, objects, and hands.
In addition to environmental factors, individual differences between people who’ve contracted SARS-CoV-2 may affect their chances of passing the virus to others.
Some studies have found that certain people emit more droplets of saliva than average when they breathe or speak. Those “super emitters” might be more likely than others to spread viruses such as SARS-CoV-2.
People with symptomatic infections might also be more likely to transmit SARS-CoV-2, compared with people who are symptom-free carriers. However, more research is needed to confirm that.
“We’re not sure about this yet, but anyone who has symptoms of the virus — fever, chills, cough, trouble breathing, body aches, sore throat, etcetera — should be presumed to be able to easily spread it,” Dr. Christopher Worsham, who specializes in pulmonology and critical care medicine at Harvard Medical School in Boston, Massachusetts, told Healthline.
“There is also likely spread happening by people who do not have symptoms and do not know they are infected but can still spread the virus,” he said.
To help limit the spread of the virus, Khabbaza and Worsham encourage people to continue to practice physical distancing, wash their hands frequently, and avoid touching their face as much as possible.
“Crowded indoor spaces where people are shoulder-to-shoulder, or activities like contact sports, should be avoided [along with] large gatherings,” Worsham said.
“For small gatherings, you still want to make sure there is enough space to maintain social distancing, plenty of soap and hand sanitizer, and encourage anyone who feels sick or has had recent contact with someone who feels sick not to come to the gathering,” he added.
Wearing face masks may also limit community spread, particularly in settings where people are in close and sustained contact with each other, Khabbaza told Healthline.
Community members who practice these strategies may help prevent super spreader events and reduce the number of new cases that occur as businesses reopen and authorities ease restrictions around gatherings.
“Remember that the virus is still out there and will be circulating for the foreseeable future,” Worsham said.
“Just because restrictions have been eased does not mean the core steps we have been taking like social distancing, handwashing, and wearing masks are no longer important,” he added.