Kids, Covid and Delta variant: What we know and what we don’t

Ways to keep children safe in school include improved ventilation, using CO2 monitors to assess how stale the air is, wearing masks and modulating class sizes.

Health worker in PPE kit interacts with a Covid patient at Guru Tegh Bahadur Covid care centre at Gurdwara Rakab Ganj Sahib in New Delhi | Representational image | ANI

For much of the pandemic, Covid-19 posed the biggest risk to adults — particularly the elderly and those with preexisting medical conditions — with children making up a small subset of the severely affected. But the emergence of the highly transmissible Delta variant has increased infections and disease even among kids, a worrisome development given that most children still aren’t cleared for vaccines and schools are set to reopen. Sam Fazeli, a Bloomberg Opinion contributor who covers the pharmaceutical industry for Bloomberg Intelligence, answers questions about the increased risks children face. The conversation has been edited and condensed.

What do we know about Covid’s risk to children at this point?

So we know children are at lower risk of severe Covid, but some risk still exists. Unfortunately, much of our experience with infection rates and severity of disease come from the past 12 months. For much of this time, vaccines weren’t widely available, so most of our efforts at keeping the virus at bay were centered on practices such as wearing masks and social distancing. Many children attended virtual school or had smaller class sizes, and there was no Delta variant. So our data is not necessarily a good guide to the future. According to the American Academy of Pediatrics, as of Aug. 5, there had been 4.3 million confirmed Covid infections among children in the U.S. Given that many kids are likely to have few or no symptoms, the actual number is most likely much higher. And the rate of infections is growing, likely because of reduced masking and social distancing with the rollout of vaccines, coupled with the surge in the Delta variant, whose characteristics make for more efficient transmission. In the week ended Aug. 5, there were close to 94,000 Covid-19 cases in children, compared with the highest peak at 211,486 recorded in the first week of January. But the worrying trend is that the percentage of total Covid-19 cases represented by children is growing: 14.3% in the week ended Aug. 5, compared with less than 2% for most of 2020. Some of this is likely driven by the fact that adults are increasingly immunized against the virus, but it’s also possible that it’s driven by behavioral changes, such as more indoor mixing.

There are reports of more hospitalizations among kids in the U.S. Does Delta increase risk because it’s more transmissible, leading to more instances of severe disease that’s still rare, or is it more dangerous?

Among Covid-19 cases in children in the U.S., 0.1% to 1.9% have led to hospitalization so far, depending on the state. But the mortality rate is much lower, with children representing no more than 0.26% of all Covid-19 deaths. All of this is history, though, and may not be representative of what is going on now.

Why are kids less susceptible to Covid in the first place?

Several factors are at play here. One is that younger children have fewer of the receptors (called ACE2) that the virus’s spike protein attaches to in order to infect human cells. A virus variant like Delta, though, which is better at multiplying more quickly in our respiratory tracts, will also become better at infecting children. That said, children have much healthier immune systems compared with those in adults, especially older adults. And they tend not to have the comorbidities, such as obesity or diabetes, that older adults have.

What are the risks of long Covid in children?

There was one report out of Italy that showed that one or two Covid symptoms lingered in as much as one-third of children for up to four months after an infection, with about a quarter having three or four persistent symptoms. Data from a U.K. study looked a bit better, finding that 4.4% of infected children between the ages of 5 and 17 had an illness that lasted at least 28 days, with only 1.8% reporting symptoms beyond 56 days. But this study only looked at symptomatic infections.

Could we get a mutant strain that’s more dangerous specifically for kids?

I am not sure. Anything is possible with this virus, but if you think about the reasons that children are at lower risk of developing severe Covid-19, then the probability would be low.

How do we keep schools safely open in this environment?

There are a few things that can make a big difference, beyond vaccination, which is now available only in the U.S. to those older than 12. The first is to improve ventilation to make sure that the same air is not recirculated without being filtered or exchanged with fresh air. Using CO2 monitors can help to assess how stale the air is. Wearing masks and modulating class sizes would also help. And, of course, regular testing.

Should we accelerate the approval of vaccines in younger kids, even though the FDA just asked for expanded studies from Moderna and Pfizer? Does that come with safety concerns?

Many of the vaccines that we get in our life are given to us when we are very young, and the human population has continued to grow at a very good clip precisely because they are safe and effective at preventing premature death from infectious diseases. So we know how to do this. The trials simply have to run their course with a good body of safety data. Once we have that, we should be good to go.

Should parents and other adults, even those who are vaccinated, change their behavior to account for delta and the risk to children?

We already know that vaccinated people can catch the virus and pass it on to others, even if they are much better protected against disease. No shot is 100% effective against an infection; their purpose is to prevent disease. This is especially true with the delta variant. Of course the risk of transmission from a vaccinated person is expected to be lower, but how much lower is not clear. So to avoid passing the virus on to their unvaccinated children, parents should do the best they can not to get infected. This means taking steps we’ve all become familiar with by now, like wearing masks in busy public spaces where social distancing is not possible and people’s vaccination status isn’t known, etc. It may seem like a step backward, but for the health and well-being of your kids, it’s a small sacrifice.-Bloomberg