(CNN) -- The US Centers for Disease Control and Prevention on Friday updated its Covid-19 schools guidance to emphasize in-person schooling is a priority in the fall, regardless of whether all mitigation measures can be implemented.
As K-12 schools will have a mix of vaccinated and unvaccinated people, the agency says it's still necessary to layer strategies such as masking and physical distancing, and most importantly, vaccinations for everyone eligible -- people age 12 and older.
Students, teachers and staff who are fully vaccinated do not need to wear masks at school. For those who aren't vaccinated or aren't eligible, consistent, correct masking remains an important safety measure, the agency said.
The CDC says its guidance does not replace local guidance and policies. Schools that are ready to transition away from pandemic precautions should do so gradually, the agency said, as community transmission reaches low levels.
"If localities decide to remove prevention strategies in schools based on local conditions, they should remove them one at a time and monitor closely (with adequate testing) for any increases in COVID-19 cases before removing the next prevention strategy," the guidance says, adding that schools need to be transparent with families, staff and the community as they do so.
Vaccines and masks
The CDC suggests schools take steps to promote Covid-19 vaccination, including offering vaccines on site, providing paid sick leave for employees to get vaccinated and excusing absences for students to get vaccinated. Covid-19 vaccines are currently available for people ages 12 and older in the US.
While the vaccinated can go without a mask, the agency recommends unvaccinated people over the age of 2 wear masks when indoors.
In general, people don't need to wear masks outdoors, but in areas with high coronavirus transmission, people who aren't fully vaccinated may still want to wear them in some circumstances.
"Consistent and correct mask use by people who are not fully vaccinated is especially important indoors and in crowded settings, when physical distancing cannot be maintained," the CDC notes.
Based on local conditions -- for example, in a school where students aren't yet eligible for vaccines or in an area with high transmission -- schools can still opt to require universal masking, even for those who are vaccinated. And, the CDC says, schools should still support vaccinated people who choose to wear a mask.
Layers of protection
The CDC guidance details layers of ways schools can prevent spread while staying open for in-person learning: "Screening testing, ventilation, handwashing and respiratory etiquette, staying home when sick and getting tested, contact tracing in combination with quarantine and isolation, and cleaning and disinfection are also important layers of prevention to keep schools safe."
Physical distancing should be practiced in schools where not everyone is vaccinated, it said, but students should not be excluded from in-person learning in order to maintain physical distancing.
Anyone experiencing symptoms that could be Covid-19 or flu should get tested, and stay home if they're sick. The guidance says unvaccinated people who were exposed to Covid-19 should quarantine, but fully vaccinated people who don't have symptoms do not need to quarantine or get tested after an exposure to a person with Covid-19.
Cohorting -- keeping people in small groups that stay together throughout the day -- can be useful to limit contacts, but it doesn't replace other key safety measures, the agency says. Cohorting people who are and are not vaccinated separately is not recommended.
The agency advises close monitoring of Covid-19 transmission, vaccination coverage, screening testing and outbreaks when making decisions about the prevention strategies needed in their area.
In a White House Covid-19 briefing on Friday, CDC Director Dr. Rochelle Walensky sounded the alarm about "new and concerning trends" in cases and hospitalizations in areas with low levels of vaccination.
"Simply put, in areas of low vaccination coverage, cases and hospitalizations are up," Walensky said. "Further, we are seeing some small clusters and larger outbreaks of Covid-19 in locations such as camps and community events where proper, hard-learned prevention strategies are not enforced and the virus is readily able to thrive."
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