Quarantine period for people exposed to coronavirus may be shortened from 14 days as CDC reviews evidence
The US Centers for Disease Control and Prevention (CDC) is currently reviewing evidence about how long people should quarantine after potential exposure to Covid-19, and the agency may soon shorten the length of the self-quarantine period. The rule is meant to keep people who might have been exposed to the virus away from others to prevent the spread of Covid-19 that can occur before they know they are sick or if they are infected with the virus without feeling symptoms.
According to health officials, they are starting to receive evidence that quarantine followed by tests might be able to shorten the quarantine period. One report suggests that the new quarantine period would likely be between seven and 10 days, down from the currently advised 14 days, and include a test to prove that the person no longer has Covid-19.
“We do think that the work that we’ve done, and some of the studies we have and the modeling data that we have, shows that we can with testing shorten quarantines. (If a test comes back negative), then their probability of going on and developing an infection after that is pretty low,” Dr Henry Walke, the CDC’s Covid-19 incident manager, told The Washington Post.
While there is a risk that some infections may be missed, Dr Walke hopes that such a measure would encourage more people to follow experts’ guidance and therefore, “worth the potential trade-off.” “Hopefully, people would be better able to adhere to quarantine if it was, for example, seven to 10 days,” he added.
The decision is not final yet and experts are discussing the exact number of days and the type of test a person would be given to exit quarantine. “CDC is always reviewing its guidance and recommendations in the light of new understandings of the virus that causes Covid-19, and will announce such changes when appropriate,” the agency noted.
According to current guidelines, people who have been in close contact with someone who has Covid-19 — excluding people who have had coronavirus within the past three months — are asked to stay at home for two weeks. This is based on how long scientists believe it can take the virus to incubate in the body.
“The incubation period for Covid-19 is thought to extend to 14 days, with a median time of 4-5 days from exposure to symptoms onset. One study reported that 97.5% of people with Covid-19 who have symptoms will do so within 11.5 days of infection,” explains the CDC.
A close contact is defined as being within six feet of someone who has coronavirus for a total of 15 minutes or more. Factors to consider when defining close contact include proximity (closer distance likely increases exposure risk), the duration of exposure (longer exposure time likely increases exposure risk), and whether the infected individual has symptoms (the period around onset of symptoms is associated with the highest levels of viral shedding).
Other parameters include if the infected person was likely to generate respiratory aerosols (was coughing, singing, shouting), and other environmental factors (crowding, adequacy of ventilation, whether exposure was indoors or outdoors).
During a briefing, meanwhile, assistant secretary for health at the Department of Health and Human Services (HHS), Dr Brett Giroir, referred to a “preponderance of evidence” that quarantine, complemented by a test, could be shortened from 14 days.
According to CNN, without specifying what shorter period is being considered, Giroir said, “We are actively working on that type of guidance right now, reviewing the evidence, but we want to make absolutely sure.” He added, “Again, these kinds of recommendations aren’t willy-nilly. They’re worked on with a variety of experts.”
The decision will be data-driven, emphasized Giroir. “Half of the people become symptomatic by day five. That’s when the virus is present. There’s a long tail of very low probability afterward. So the postulate is...if you get a test on day seven or day 10, particularly, can that shorten your quarantine from 14 days to perhaps 10 days? People are much more likely to listen to a 10-day quarantine than a 14-day quarantine, (so a potentially shorter period) might actually improve our public health responses,” he reasoned.