The US Centers for Disease Control and Prevention on Monday shortened the recommended time for isolation for people testing positive for COVID-19 from 10 days to 5 days, if asymptomatic. The CDC also shortened the recommended quarantine period for those exposed to the virus to 5 days, if they are vaccinated, while those who have received their booster do not need to quarantine.
Those testing positive, along with those exposed and having received the initial dose(s) of the vaccine but no booster, are encouraged to use a mask around others for the next 5 days following the 5-day isolation/quarantine period, according to CDC guidance. Those exposed but up to date on boosters are encouraged to wear a mask for 10 days even if they do not quarantine.
“The change is motivated by science demonstrating that the majority of SARS-CoV-2 transmission occurs early in the course of illness, generally in the 1-2 days prior to onset of symptoms and the 2-3 days after,” the CDC said in a statement. “Therefore, people who test positive should isolate for 5 days and, if asymptomatic at that time, they may leave isolation if they can continue to mask for 5 days to minimize the risk of infecting others.”
Regarding exposures, the CDC statement reads, “For people who are unvaccinated or are more than 6 months out from their second mRNA dose (or more than 2 months after the J&J vaccine) and not yet boosted, CDC now recommends quarantine for 5 days followed by strict mask use for an additional 5 days. Alternatively, if a 5-day quarantine is not feasible, it is imperative that an exposed person wear a well-fitting mask at all times when around others for 10 days after exposure.”
The CDC said for all those exposed, the best practice would also include a test for SARS-CoV-2 at day 5 after exposure. If symptoms occur, individuals should immediately quarantine until a negative test confirms symptoms are not attributable to COVID-19.
Isolation relates to behavior after a confirmed infection. Quarantine refers to the time following exposure to the virus or close contact with someone known to have COVID-19.
“Both updates come as the Omicron variant continues to spread throughout the U.S. and reflects the current science on when and for how long a person is maximally infectious,” the CDC said. “… Data from South Africa and the United Kingdom demonstrate that vaccine effectiveness against infection for two doses of an mRNA vaccine is approximately 35%. A COVID-19 vaccine booster dose restores vaccine effectiveness against infection to 75%.”
CDC Director Dr. Rochelle Walensky said the Omicron variant has the potential to impact all facets of society.
“CDC’s updated recommendations for isolation and quarantine balance what we know about the spread of the virus and the protection provided by vaccination and booster doses,” Walensky said. “These updates ensure people can safely continue their daily lives. Prevention is our best option: get vaccinated, get boosted, wear a mask in public indoor settings in areas of substantial and high community transmission, and take a test before you gather.”