Becker's Clinical Quality & Infection Control

10 INFECTION CONTROL Incubation shorter with each new COVID-19 variant, study shows By Erica Carbajal W ith each new COVID-19 variant, the interval between exposure and symptom development appeared to shorten, according to a study published Aug. 22 in JAMA Network Open. COVID-19 is known to have a longer incubation period than other respiratory viral infections such as the flu, helping to explain why health agencies initially recommended a 14-day quarantine aer exposure. Researchers from Peking University and Tsinghua University in Beijing analyzed data from 142 studies involving 8,112 patients to estimate whether the incubation period changed with different variants of the SARS-CoV-2 virus. ey found the mean incubation period pooled from all of the studies analyzed was 6.57 days. at fell to an average of five days for the alpha variant; 4.5 days for beta, 4.4 days for delta and 3.4 days for omicron, the findings showed. "Incubation period is one of the most important epidemiological parameters of infectious diseases," researchers said. "Identifying the incubation period of different variants is a key factor in determining the isolation period." e CDC recommends people exposed to COVID-19 quarantine for five days followed by mask use for an additional five days. n Misinterpreted guidance may fuel a COVID-19 uptick, Northwestern expert says By Erica Carbajal W hile COVID-19 hit a plateau in the U.S. this sum- mer, a misinterpretation of eased CDC guid- ance may contribute to an uptick this fall and winter, according to an epidemiologist at Chicago-based Northwestern Medicine. As of Sept. 16, COVID-19 cases had fallen nationwide for eight consecutive weeks, according to CDC data. Global- ly, new weekly COVID-19 deaths also reached their low- est point since the start of the pandemic in March 2020, according to a Sept. 14 report from the World Health Or- ganization. For the week ending Sept. 11, 11,000 deaths were reported, marking a 22 percent decrease from the previous week. But of course, all of this is subject to change come fall and winter when cooler weather moves in and people gather indoors and travel for the holidays. "I think we're going to see fairly rapid spread," said Mer- cedes Carnethon, PhD, vice chair of the department of pre- ventive medicine at Northwestern University's Feinberg School of Medicine. That may likely be in part because of misinterpreted guidance. In August, the CDC released updated COVID-19 guidance that did away with quarantine after exposure, regardless of vaccination status. The updated guidance largely focuses on mitigating the risk of severe disease, rather than infec- tion itself, and underscores the importance of vaccination, boosters and treatment. "I think a lot of people are considering it a little less seri- ously given the updated guidance about whether or not you need to quarantine with exposure," Dr. Carnethon told Becker's. "I think the most fearful thing is that people won't take infections and exposures to positive people as seri- ously and that they'll continue circulating." There are details in the guidance that may be overlooked, particularly surrounding recommendations for isolation. The CDC says people with COVID-19 may end isolation after five days if fever-free for 24 hours without medica- tion, though a mask should be worn through day 10. The agency also advises immunocompromised people isolate for 10 days, not five. Dr. Carnethon expressed concern that employers may be less lenient and expect people who were out with COVID-19 to come back to work sooner than they would have earlier in the pandemic. "I'm a little concerned that people won't pay attention to those nuances in the guidance and [infected people] come back prematurely and thus place higher-risk people at risk," she said. And just because there are more tools available now to pre- vent severe illness, the nation's healthcare system isn't out of the woods from facing a significant COVID-19 burden. Based on past experience in the winter months, Dr. Carne- thon said hospitals could again feel significant strain from the disease, both from a rise in the number of infected pa- tients who may need care and staff who are out sick. "We're going to see shortages in high-needs areas: nurs- ing homes, rehabilitation facilities where people may go," she said. "Providers who spend a lot of time face to face and one-on-one with patients have throughout the pan- demic shown a higher risk of being infected. That includes nursing staff in hospitals, registered nurses and other care providers in long-term care facilities." n

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