DETROIT – The Centers for Disease Control and Prevention reviewed and revised the recommended length of time necessary to quarantine after a coronavirus exposure.
Previously, if you were exposed to a person infected with SARS-CoV-2, the recommendation was that you quarantine for 14 days. That’s based on good evidence that most people will have developed symptoms by day 14 and, even if they don’t have symptoms, the risk of being infectious past day 14 is also low.
The problem is asking people to stay home for 14 days with a potential loss of income and all the inconveniences that quarantine brings creates a strong disincentive to report an exposure and abide by the recommendation.
The alternative the CDC is offering will hopefully maximize adherence and still reasonably minimize risk.
The change that the CDC announced Wednesday is that after an exposure, the recommended quarantine period would shorten to 10 days without testing and be reduced to 7 days if someone has a negative test.
However, the timing of the test from the day of exposure is important because the majority of people with COVID-19 will develop symptoms five days from the time they were exposed -- and testing in that timeframe has the highest yield.
There’s also good evidence that after seven days the infectiousness of a person begins to decline significantly and a 10-day quarantine would contain the majority of individuals who are infected.
“If you isolate for 10 days, the probability that you will start replicating the virus after that is about 1%,” said CDC director Dr. Robert Redfield. “So it’s a balance. It’s not that 14 days is bad, it’s just that’s how does society wants to balance it.”
And balance is the important point. Based on what we know, the CDC didn’t say that 14 days is wrong and they are still recommending it when possible.