FAQ on Coronavirus: Does the 6 Feet/15 Minutes Rule apply to The Delta Variant of Coronavirus?
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We answer common questions each week about the coronavirus crisis. Send us an email at goatsandsoda@npr.org if you have any questions. The subject line should be: "Weekly Coronavirus Question." You can find an archive of our FAQs right here.
Two numbers have been mentioned since the inception of COVID. They are linked to reducing the chance of someone else getting the virus. We were instructed to keep at least 6 feet from other people. That's a cutoff time for close contact. The delta variant is more contagious. It should be... It should be... What's the best recommendation?
First, the Centers for Disease Control and Prevention 6-foot, 15-minute definition was never a good approximation. Dr. Leana Wein, an emergency physician and professor of public health at George Washington University, points this out.
She says, "There wasn't anything magical about 6 feet and 15 min." "But, we must draw the line somewhere."
Based on research from the late 1800s that looked at how far infectious droplets could travel in the air before reaching the ground, the distance was determined. It was not intended to be an absolute guarantee. COVID-19 can also spread through aerosols that travel over 6 feet.
Video by Xueying, Kaz Fantone and Marc Silver/NPR YouTube
William Hanage, an associate professor of epidemiology at Harvard School of Public Health, says that "It was interpreted too often as a kind of rule that would follow the virus." "It is obvious that sitting more than six feet from a highly infectious person in unventilated spaces for an hour would not make you "safe" immediately.
He says that the risk may be slightly lower, but it would not be zero.
Abraar Karan, a Stanford University infectious disease fellow, said that the CDC used distances of 6 feet and exposure times of 15 minutes to determine whether someone was more likely to get infected.
"As with any pre-condition, there are exceptions. For example, if you were exposed more virus over a shorter time period (as you might expect from delta which can cause viral loads much higher than the previous dominant strain) or if you were less virus over a longer time period or in close proximity.
Karan states that the CDC's website now clearly points out that aerosolization can transmit transmission beyond 6 feet indoors.
How can you assess your risk?
To lower your risk of getting sick, there are some things you can do: Get vaccinated, wear an mask, wash your hands and avoid anyone who is ill. Experts recommend thinking more broadly in terms of distance and time.
Karan states, "It is important that people think about this in terms more likely and less likely than absolutes like 6 feet or 15 minutes."
Wen points out that it's okay to rely solely on your common sense. "I would simply say to use common sense, and a higher level of suspicion [now that Delta is in charge].
Karan states, for example, that "emphasize the fact that the closer you are with others, the more likely transmissions can occur." Karan also says that "the further away you are, the less likely it is." You are more likely to be near someone if you spend longer than usual. Also, time spent is important, wearing masks is important, and being outside where drops can't accumulate matters. It also matters how infectious someone else may be.
Hanage suggests that you consider the following factors: whether people have not been vaccinated, whether they are indoors, lack of ventilation, mask use, duration, number of infectious contacts and total inoculum, which is the total number of viral particles. We'll let you know how many viruses you might have been infected by, but we won't give you any information. It's more likely that it is much higher with delta being the primary variant.
How do you determine when it is time to quarantine or test?
Again, use your common sense, Wen urges. "If you were at an event with someone who tested positive but don't remember that person or were not in close proximity to them, then you probably don’t need to quarantine. If you have vulnerable family members or had a questionable exposure, it is advisable to get tested.
She says that you should "use a very high level of suspicion" when living with vulnerable people. If you see someone who tests positive after five minutes, you should get tested. But, you must wait at least three days to confirm your suspicions or you could be given an incorrect result.
Karan states that transmission is a complicated process. This cannot be captured in a set amount of minutes or feet.
Sheila Mulrooney Eldred, a freelance journalist covering health in Minneapolis, is Sheila Mulrooney Eldred. She has written extensively about COVID-19 for many publications including Medscape and Kaiser Health News, Science News for Students, and The Washington Post. More at sheilaeldred.pressfolios.com. Follow @milepostmedia on Twitter
