In an indication of just how fast the Delta variant is changing the public health playbook in schools and other aspects of life, the CDC reversed course two-and-a-half weeks after updating its guidance to allow vaccinated students and staff members to be maskless in schools.
“CDC recommends that everyone in K to 12 schools, wear a mask indoors, including teachers, staff, students and visitors, regardless of vaccination status,” said CDC director Rachel Walensky during a telepress conference on July 27, during which she also called for vaccinated individuals to resume masking in counties that have more than 50 to 100 cases in a seven day period per 100,000 people.
“We have new science related to the Delta variant that requires us to update the guidance regarding what you can do when you are fully vaccinated,” she said. “The Delta variant is showing every day, its willingness to outsmart us and to be an opportunist in areas where we have not shown a fortified response against it.”
She added, “Children should return to full time in person learning in the fall with proper prevention strategies in place.”
New Data on Vaccination and Viral Loads
The change in policy was fueled by rising case counts in much of the country and recent data from infection clusters indicating Delta produced higher viral loads in vaccinated individuals who contracted the virus than previous strains. “When we examine the rare breakthrough infections, and we look at the amount of virus in those people, it is pretty similar to the amount of virus in unvaccinated people,” Walensky said. “We are now continuing to follow those clusters to understand the impact of forward transmission of those vaccinated people.”
The higher viral loads observed suggested that vaccinated individuals who do get sick, have the potential to forward transmit, with the same capacity of an unvaccinated person, Walensky said. “Unlike the Alpha variant that we had back in May, where we didn't believe that if you were vaccinated you could transmit further. … With the Delta variant, we're seeing that it's actually possible, if you're a rare breakthrough infection that you can transmit further,” she said.
But vaccinated individuals still appear less likely to get infected in the first place.
“The highest spread of cases and severe outcomes is happening in places with low vaccination rates, and among unvaccinated people, this moment, and most importantly, the associated illness, suffering and death could have been avoided with higher vaccination coverage in the country,” Walensky said.
What The New Guidance Means for Schools
The increasing likelihood that vaccinated individuals can spread the disease and low vaccination rates are heightening concerns over Delta as the school year approaches.
“When we released our school guidance on July 9, we had less Delta variants in this country, we had fewer cases in this country, and importantly, we were really hopeful that we would have more people vaccinated, especially in the demographic between 12 to 17 years old,” Walensky said. “Next week, we have many school systems that are starting around the country and children 11 and less are not going to be able to be vaccinated.”
She added, only 30 percent of kids 12 to 17 are fully vaccinated, and the new mask guidance represents “a real effort to try and make sure that our kids can safely get back to full in-person learning in the fall.”
In a released statement, U.S. Secretary of Education Miguel Cardona said: "Students are provided the best opportunity to learn and thrive when learning in person. We know the best way to safely do this is to get as many people age 12 and older vaccinated. Given the recent trends in COVID spread due to premature relaxation of prevention strategies by unvaccinated individuals and lagging vaccination rates in some parts of our country, we support the recommendation for masking in K-12 schools. We must do everything to ensure that our students do not have to compromise any more of their educational experiences due to increases in community spread. The Department stands ready to work with schools, families, and communities to implement these recommendations from the CDC and ensure all students in every corner of the country can return to school in-person, full time this fall."
The decision to reverse course on mask mandates for vaccinated individuals both in schools and in some instances out of school was a difficult one, but deemed necessary.
“Public health experts, scientific experts, medical experts, when I've shown them these data have universally said that this required action,” Walensky said. “I felt that when I saw the data myself … This was not something that we took lightly and [it is] something that I know weighs heavily with me and with all of America.”