CDC Director encourages schools to stay open with Covid-19 precautions

CDC Director Rochelle Walensky on Friday also addressed criticism from some doctors and public-health experts that she and the CDC haven’t clearly communicated recent changes to the agency’s isolation and quarantine guidelines.

“We’re in an unprecedented time with the speed of Omicron cases rising, and we are working really hard to get information to the American public and balancing that with the realities that we’re all living with," Dr. Walensky said. “This is hard, and I am committed to continue to improve as we learn more about the science and to communicate that."

The CDC last week updated its Covid-19 guidance for isolation and quarantine, cutting the time that people who have been exposed or tested positive for the virus should stay away from others.

Quarantine refers to someone staying away from others when they may have been exposed to the virus but hasn’t yet tested positive themselves; people isolate when they are sick or have a confirmed infection. The CDC now recommends that people can exit from isolation after five days, as long as they haven’t had a fever in 24 hours and their symptoms have improved. People should wear a well-fitted mask around others for an additional five days, the CDC said. Otherwise, people should wait for symptoms to resolve or isolate for the full 10 days, the CDC says.

“We do know that the maximum contagiousness during your period of being sick is in the day or two before your symptoms and the two to three days after your symptoms," Dr. Walensky said. “The guidance is very clear that you should not leave isolation if you’re still symptomatic."

The agency on Thursday updated its guidance for isolation and quarantine at schools, bringing it closer in line with the less stringent recommendations for the general population. Many schools have struggled with staying open after the holiday break, after teachers and staff have gotten sick or tested positive for a Covid-19 infection.

Becky Pringle, president of the National Education Association, reacted cautiously to the revised CDC guidance. Ms. Pringle said districts should consistently use layered mitigation measures such as mask-wearing to slow the spread of the virus. Any decisions to implement the five-day protocol should be made locally with input from teachers, parents and medical experts, she said, and the effects should be closely tracked.

“Each school district and community needs to bring their stakeholders together, and they need to make that decision," she said.

Public-school classes in Chicago were canceled for a third day Friday as officials and the teachers union remained at an impasse over Covid-19 protocols as new cases remained at record levels in the nation’s third-largest city. City leaders have said teachers who didn’t report to work wouldn’t receive pay.

Dr. Walensky said that while she understood concerns among parents and teachers about risks posed by the Omicron variant, the CDC’s updated guidance and established safety measures provide schools with the tools to remain open for the rest of the school year.

“Vaccines, masks, increased ventilation and testing are all important layers of prevention that keep our children safe and keep them in school for in-person learning," she said.

Covid-19 tests, particularly rapid at-home tests, have been hard to find in recent weeks amid the Omicron surge. The CDC has stuck by its guidance to not recommend a negative antigen test to leave isolation despite pushback from some public-health experts, but it has provided a best practice for those who want to do so.

“A negative antigen test doesn’t necessarily mean that there’s an absence of virus," said Henry Walke, director of the CDC’s Center for Preparedness and Response. “So regardless of the test result, wearing a well-fitting mask after those five days of isolation is still recommended."

The Food and Drug Administration earlier this week authorized the use of a booster Covid-19 dose for adolescents 12 to 15 years old and cleared a third dose for children with certain compromised immune systems ages 5 to 11.

The CDC on Friday published a report that found, across 24 U.S. pediatric hospitals from July to December 2021, about 95% of adolescents aged 12 to 18 who were hospitalized with multisystem inflammatory syndrome after a Covid-19 infection were unvaccinated. No fully vaccinated patients with MIS-C needed respiratory or cardiac life support, as opposed to 39% of unvaccinated patients, the report said.

Pediatric hospitalization rates for Covid-19 have risen across the country to the highest point during the pandemic. But rates of hospitalization for children are still the lowest, compared with all other age groups, Dr. Walensky said. An average of 766 children under the age of 18 with Covid-19 were admitted to the hospital each day from Dec. 29 to Jan. 4, according to CDC data. Some children are asymptomatic but tested positive after coming into the hospital for something else, she said.

—Joe Barrett and Scott Calvert contributed to this article.