On Monday, the Centers for Disease Control and Prevention (CDC) announced new COVID guidelines, shortening the recommended isolation times for those who test positive for COVID-19 from 10 days to five days if they don’t have symptoms—regardless of vaccination status—with the added stipulation that they wear a mask around others for at least an additional five days. “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 the onset of symptoms and the 2-3 days after,” the CDC stated in the press release. Additionally, the CDC shortened the recommended quarantine time for unvaccinated individuals exposed to the virus to five days, specifying that those who are vaccinated need not quarantine at all. “For people who are unvaccinated or are more than six 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,” they write. “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. Individuals who have received their booster shot do not need to quarantine following exposure, but should wear a mask for 10 days after the exposure.” On Wednesday, CDC Director Rochelle Walensky explained to NPR’s Ari Shapiro why the health organization opted to halve the recommended quarantine period for asymptomatic people. She attributed it to a “confluence of events” and a “confluence of science” gathered from two years of research surrounding the wild type variant, Alpha variant, Delta variant, and Omicron variant. “What we have learned during all this period of time is that early in the course of illness, in the one to two days prior to the onset of symptoms and then in the two to three days after the prior onset of symptoms is really when the vast majority of transmission occurs. So in that five-day window is really where most of that transmission is happening.” She added that the CDC took into account the social consequences of keeping people out of work for extended periods of time, especially with the “really large anticipated number of cases” of Omicron. “As we’ve seen that, we also want to make sure that we can keep the critical functions of society open and operate,” she continued, specifically noting the recent cancellation of airline flights and health care workers shortage.
Is shortening the isolation period safe?
Dr. Shira Doron, MD, Infectious Disease Physician and Hospital Epidemiologist at Tufts Medical Center, endorses the CDC’s decision to shorten isolation times, noting that the previous isolation time of 10 days was always on the conservative side and established in the pre-vaccination period of the pandemic. Now that many people have gotten fully vaccinated or boosted, the virus is less deadly for the majority of the population. “It’s a manifestation of where we are in the pandemic in the post-vaccination era. It would make sense regardless of Omicron to revisit whether and when it’s time to rethink the isolation,” she explains. “We’re seeing massive societal harm from industries not being able to function, society not being able to function, people not being able to do the things they need to do,” she continued. Dr. Doron admits that there might be some people who are still contagious at day six, seven, eight, nine, or 10. “But you know what, there are a ton of people walking around out there at the height of contagiousness and they don’t even know it, probably way more than those people who might be released early from isolation and might have a little bit of residual contagiousness,” she points out.
Why the CDC didn’t limit guidance to people who are vaccinated
Keep in mind that the new guidelines are for both vaccinated and unvaccinated individuals. Dr. Doron notes that with Delta, there was a difference in transmissibility between vaccinated and unvaccinated individuals, with research finding that both groups had a similar viral load at the start of the infection with vaccinated clearing the virus more rapidly. However, it is still unclear if this is the case with Omicron, especially because our vaccine-induced antibodies aren’t as successful in neutralizing the virus. “I don’t think we can say that vaccinated have a low viral load with Omicron at five days the way we said it at Delta, and that’s why it makes sense that the CDC didn’t limit guidance to people who are vaccinated,” Dr. Doron points out. One aspect of the new guidanceDr. Darren P. Mareiniss, MD, FACEP, Assistant Professor of Emergency Medicine, Sidney Kimmel Medical College—Thomas Jefferson University in Philadelphia, PA, isn’t too happy about, is the CDC’s recommendation that people return to work with a mask after five days of isolation if symptomatic individuals have resolving symptoms and no fever. “If patients are still symptomatic, I think they should isolate until they have no fever for 24 hours and symptoms are resolved,” says Dr. Mareiniss, noting that hospitals are currently “overwhelmed” with COVID patients, with many at capacity. “Otherwise, they should probably continue to isolate the standard 10 days. I worry that they will still be infectious and spread the virus to others.” Next up, Here’s What You Can Expect COVID Symptoms to Look Like Day by Day
Sources
Centers for Disease Control and Prevention: CDC Updates and Shortens Recommended Isolation and Quarantine Period for General PopulationCenters for Disease Control and Prevention: Quarantine and IsolationNPR: CDC Director on New Isolation RulesShira Doron, MD, Infectious Disease Physician and Hospital Epidemiologist at Tufts Medical CenterDr. Darren P. Mareiniss, MD, FACEP, Assistant Professor of Emergency Medicine, Sidney Kimmel Medical College – Thomas Jefferson University in Philadelphia, PA
