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CDC Issues New Warning on Time it Takes to Get Infected

A real-world case study highlights the importance of wearing a mask.
Two people wearing surgeon masks is sitting in a cafe and chatting

The Centers for Disease Control and Prevention announced on Wednesday that it has expanded its definition of someone who was in "close contact" with a person diagnosed with coronavirus. It has many public health implications, underscoring the importance of mask wearing, expanding the remit of contact tracers, and potentially affecting guidelines for self-quarantining and who should be tested after exposure. Read on, and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had Coronavirus.

Very short exposures may cause infections

The CDC's previous definition of a "close contact" was someone who spent at least 15 consecutive minutes within six feet of someone with COVID-19. The agency's new guidance changes that definition to someone who was within six feet of an infected person for 15 cumulative minutes or more over a 24-hour period, starting from two days before the onset of their illness or a positive test result.

The change was motivated by a report published in MMWR about a 20-year-old Vermont prison employee who contracted coronavirus after having 22 interactions during an eight-hour shift with six people who tested positive for COVID-19 the following day.

All the interactions were brief, but they added up to about 17 minutes overall. The correctional officer spent only fleeting time with the inmates—performing tasks like opening and closing cell doors, conducting health checks, collecting dirty laundry, opening the doors to shower and recreation rooms and dispensing medicines.

Despite taking safety precautions, the person was infected by at least one of the six inmates, who wore microfiber cloth masks at least part of the time. "During all interactions, the correctional officer wore a microfiber cloth mask, gown, and eye protection," wrote the report's authors.

RELATED: 11 Symptoms of COVID You Never Want to Get

The bottom line: Wear a mask

"In an MMWR published today, CDC and Vermont health officials found that multiple, short and non-consecutive exposures to persons confirmed to have COVID-19 led to transmission." the CDC said in a statement.

"This article adds to the scientific knowledge of the risk to contacts of those with covid-19 and highlights again the importance of wearing face masks to prevent transmission," the agency added.

For several months, it's been apparent to scientists that coronavirus can be transmitted by people who have no symptoms of the illness. Officials have said it's important to wear a mask mostly to protect vulnerable people from the coronavirus you may unwittingly be carrying.

"A mask can protect other people from the virus-containing particles exhaled by someone who has COVID-19. As many as half of all people who have COVID-19 don't show symptoms, so it's critical to wear a mask because you could be carrying the virus and not know it," the CDC said. "While a mask provides some limited protection to the wearer, each additional person who wears a mask increases the individual protection for everyone. When more people wear masks, more people are protected."

As for yourself, do everything you can to prevent getting—and spreading—COVID-19 in the first place: Besides wearing a face mask consistently in public, get tested if you think you have coronavirus, avoid crowds (and bars, and house parties), practice social distancing, only run essential errands, wash your hands regularly, disinfect frequently touched surfaces, and to get through this pandemic at your healthiest, don't miss these 35 Places You're Most Likely to Catch COVID.

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