(CNN) Five full days a week, every week: After more than a year of remote learning, hybrid schedules and missed experiences, getting back to school -- "normal" school -- is all many parents and students want. But with Covid-19 surging again in some US states and concerns over new virus variants growing, what classrooms will look like exactly in the fall is still evolving.
The US Centers for Disease Control and Prevention issued new guidance last week on the importance of having all schools opened for in-person, full-time instruction in the fall. To safely keep schools open, the CDC recommended what it calls "a layered mitigation strategy." This is a systematic strategy involving multiple interventions to reduce risk, such as including the use of indoor masks for unvaccinated students and teachers.
What happens if schools reopen but don't enforce these procedures? For example, what should parents do if schools don't require masks? Should vaccinated children over 12 feel comfortable removing their masks in schools? And when might vaccines be available for younger children?
We asked CNN Medical Analyst Dr. Leana Wen for her thoughts. Wen is an emergency physician and visiting professor of health policy and management at the George Washington University Milken Institute School of Public Health. She's also author of a book coming out later this month, "Lifelines: A Doctor's Journey in the Fight for Public Health."
CNN: With the more contagious Delta variant circulating, are these CDC guidelines enough to keep students, teachers, staff and their families safe?
Dr. Leana Wen: Yes. At this point, we have plenty of data that schools can be very safe from a Covid-19 transmission standpoint if mitigation measures are followed. The CDC has been very thoughtful in its guidance, which cites numerous scientific articles to explain its strategic approach.
Specifically, the CDC is saying that indoor masking is important for unvaccinated people. That's because the unvaccinated are still at high risk for getting and transmitting coronavirus. Vaccination protects people very well, so, consistent with the rest of the guidance for vaccinated individuals, the CDC is saying vaccinated people don't need to mask indoors. It recommends weekly testing for unvaccinated students and staff, which could be more frequent for individuals involved in certain, higher-risk extracurricular activities. And there are other mitigation measures, too, such as an investment in improved ventilation using federal Covid relief funds and keeping students at home when they are having any possible symptoms of Covid-19. All these measures added together will substantially reduce transmission risk in schools.
CNN: But what about not being able to have 6-foot physical distancing? The CDC is saying this is no longer required.
Wen: For many schools, it wouldn't be possible to have all children back full time and still keep 6-foot distancing. That's why the CDC says to try to keep 3-foot distancing, and to employ other mitigation measures to make up the difference if needed.
Here's where the layered mitigation strategy is so important. Think of it like wearing layers. If it's not very cold outside, having one or two layers of protection is enough. If it's very cold, you need multiple layers. If you remove one layer, you could replace it with another, different type of layer, and it still does the job.
Physical distancing is a powerful layer of protection. If it's no longer there, you could replace it with other layers. In this case, even if there is no distancing but there is vaccination, masking and regular testing, that would protect against coronavirus transmission. The goal is to reduce community rates of Covid-19 as much as possible. In areas of low transmission, you don't need to employ all these layers anymore -- just as you wouldn't need to wear a lot of layers of clothing after the weather warmed up.
CNN: When can kids stop wearing masks in schools?
Wen: Again, I'd think of this using the weather and layers analogy. If the vaccination rate in a community is very high and the level of coronavirus is very low, it's conceivable that indoor masking no longer needs to be enforced. However, we are not there yet as a country, and that's why the CDC is saying that masks are required indoors for unvaccinated people.
CNN: What does the latest data tell us about infection rates for children and severity of their symptoms?
Wen: During the pandemic, more than 4 million children have been diagnosed with Covid-19. As more adults are now vaccinated, children make up a larger proportion of those getting infected; as of July 8, children make up more than 1 in 5 in new infections.
The Delta variant is the most contagious variant we have seen, which may mean that unvaccinated children are more likely to transmit and to get infected with this variant than before. It's not clear that children become more ill -- and we need to keep in mind that in general, children with Covid-19 infections tend to get much less severely ill than adults. However, children can have long-term consequences from Covid-19 that last months or potentially even years.
CNN: There are at least five states that are not allowing schools to implement mask mandates. What should parents do if their schools don't require masks?
Wen: This is tricky. I'd first inquire with the school administrators to see how many children and staff are still likely to be wearing masks. If nearly everyone wears a mask anyway, even if it's not required, that would be fine.
On the other hand, if few others are going to wear masks, you should consider whether your child could still do it. If they can, it would still protect them, but it's possible that peer pressure is such that they might not keep their mask on. In that case, you should be asking about what other mitigation measures are in place. If there are -- say, the schools have improved ventilation, and they also implement once- or ideally twice-weekly testing for unvaccinated students and teachers -- I'd feel better (in this sense, testing replaces the mask).
CNN: What's the risk to children under 12 if teachers are unvaccinated and not masking?
Wen: They are not supposed to be doing that, but I think this question is getting at the problem that the CDC is not offering any guidance for how to verify vaccination status. For many schools, it will probably be an honor code, and if teachers are not wearing masks, there is no way to know whether it's because they're vaccinated and following the guidance, or if they're unvaccinated and defying the guidance.
Whenever layers of mitigation are removed, they should be replaced by other layers. If there are unvaccinated, unmasked teachers around, this does add risk. The risk can be reduced if that teacher is regularly tested and keeps a good distance away from students, but ideally, this situation does not occur in the first place.
CNN: What if vaccinated teachers get breakthrough infections? Can they be a risk to unvaccinated children?
Wen: I'm actually much less concerned about this. Vaccination protects very well against getting Covid-19 -- and spreading it. It's still theoretically possible that a vaccinated person can be ill and shed enough virus to infect others, but my concern is much more about the unvaccinated people spreading coronavirus to one another.
CNN: What about children in middle school and high school, where some children are vaccinated and some are not? If my child is vaccinated, is it OK for him to take off his mask at school or at after-school activities?
Wen: You should follow the regulations and the norms of your school. Some schools might still require masks, because they are not asking for proof of vaccination. Others might have such high vaccination rates that every kid in a classroom is vaccinated; in that case, it's definitely safe for your vaccinated child to go without a mask. If your child is not vaccinated, though, he should be wearing a mask in indoor spaces.
I'd definitely make sure that you monitor what your child is doing after school. It would be a shame to follow strict Covid-19 protocols during school, only to engage in high-risk activities outside of the classroom that add unnecessary risk to your child and your family. The rule of thumb is that if your vaccinated child is around other vaccinated kids, there is extremely low risk, and they can engage with one another without masks, distancing or other coronavirus restrictions. The risk becomes a little higher every time there are unvaccinated people in the group. And if your child is unvaccinated, they really shouldn't be indoors with other unvaccinated individuals without masks.
CNN: Will kids under 12 be able to be vaccinated before the school year?
Wen: That's unlikely. Even if a vaccine were authorized right now for younger children, it would take several weeks to complete the two-dose inoculations and wait two weeks beyond that to be deemed fully vaccinated.
It's estimated that vaccines for younger children may be available later this fall, with elementary-age children likely becoming eligible first, followed by toddlers and babies. For now, before a vaccine is available, younger unvaccinated kids should wear masks when in indoor, crowded settings around others in their peer groups.
The point of the CDC's guidelines is to emphasize that it's really crucial for our kids to be back for in-person school. Our children have lost so much during the pandemic. It's our obligation to do our part and implement the necessary infection control protocols so that they can be back learning, safely, in the fall.