The Centers for Disease Control and Prevention faced fresh blowback on Sunday for its muddled messaging on the agency’s new isolation and quarantine guidance.
The C.D.C.’s new guidelines, released on Dec. 27, say that people infected with the coronavirus can end isolation, in most cases, after five days instead of 10 and do not need a negative result on a virus test to do so. But some experts have said that five days might be too short, and that letting people mingle with others before first testing negative was risky.
On Sunday, Dr. Rochelle Walensky, the agency’s director, fielded questions about her decision to drop the testing requirement, and maintained that antigen tests are less sensitive to the Omicron variant, which is surging across the United States, than to previous versions of the virus.
“We have ever-evolving science with an ever-evolving variant, and my job is to provide updated guidance in the context of rapidly rising cases,” she told “Fox News Sunday.”
But other experts disagreed with that assessment, saying antigen tests, while flawed, only missed Omicron cases very early in the course of infection.
“I think they are a bedrock of our long-term strategy for managing this virus,” Dr. Ashish Jha, dean of the Brown University School of Public Health, said on ABC’s “This Week.”
The debate on testing reflects broader disagreement over how best to cope with a virus that seems here to stay. With only about 63 percent of the population fully vaccinated, the virus could seed large outbreaks and overwhelm hospitals for the foreseeable future.
On Thursday, six prominent health experts who advised President Biden’s transition team called for a new strategy to help Americans live with the virus long-term. Among the recommendations: easy access to affordable tests, more aggressive use of vaccine mandates, “comprehensive, digital, real-time” data collection by the C.D.C. and faster development of vaccines and treatments.
The Supreme Court seemed unlikely on Friday to allow a cornerstone of the Biden administration’s plan to fight the virus. While the court may greenlight a vaccine mandate for health care workers at facilities that receive federal funding, it seemed skeptical of the legal basis for a broader mandate that would affect 84 million American workers.
That mandate would compel all companies with 100 or more employees to require either vaccinations or weekly testing and masks.
“The Supreme Court has to recognize that Covid in the workplace is a real health threat,” said Dr. Zeke Emanuel, one of the authors of the proposed pandemic strategy and a medical ethicist at the University of Pennsylvania. Vaccine mandates are the best protection against the virus, particularly for frontline workers, he said.
“For the Supreme Court to take that away in the midst of an emergency seems to me to be very wrong,” he added.
Dr. Walensky did not respond to a question about the utility of a vaccine mandate but noted that unvaccinated children and adults are at significantly higher risk from the virus than people who are fully vaccinated and boosted.
In children 4 years old and younger, who are not yet eligible for vaccination, hospitalizations are at the highest levels since the beginning of the pandemic, the C.D.C. reported on Friday.
“The vast majority of children who are in the hospital are unvaccinated,” Dr. Walensky said on Sunday. “And for those children who are not eligible for vaccination, we do know that they are most likely to get sick with Covid if their family members aren’t vaccinated.”
Omicron is milder than previous variants, and even young children seem less likely to need ventilators than those admitted during previous surges, doctors have said.
Dr. Walensky also clarified confusion over the number of children hospitalized with Covid. On Friday, Justice Sonia Sotomayor mistakenly said that 100,000 children with Covid had been admitted to hospitals nationwide. The real number is closer to 3,500, Dr. Walensky said.
“While pediatric hospitalizations are rising, they’re still about 15-fold less than hospitalizations of older age demographics,” she added.