By June, moreover, 40% of youngsters aged 5 to 11 had been infected with the coronavirus, according to federal scientists. Experts on the outside aren’t so sure.
On Tuesday, while advisers to the Food and Drug Administration debated the use of the Pfizer-BioNTech Covid-19 vaccination in children aged 5 to 11, a stunning number emerged. According to one federal expert, the coronavirus had infected approximately 42 percent of these infants by June.
That number was significantly higher than anyone had anticipated. However, numerous experts suggested in interviews that the estimate from the Centers for Disease Control and Prevention may have exaggerated the percentage of children who were infected. The proportion was calculated using tests with a high probability of “false positives,” which indicate the existence of antibodies when none exist.
Even if a large number of children have been affected, parents should not assume that their children are immune to the virus and do not require vaccination. Immunization, according to Scott Hensley, an immunologist at the University of Pennsylvania, “will solidify that protection now and against future viral variations.”
“The data show that even if they had previously been exposed, they would benefit from the vaccine,” he said of children. “Vaccination has very few risks, but it has a lot of benefits.”
Is it true that 42% of younger children are immune to the coronavirus?
No, most likely not. The C.D.C. estimate was based on the results of tests performed on a small number of children who had blood drawn for routine medical care or other illnesses. According to Akiko Iwasaki, an immunologist at Yale University, “that is not a representative sample of the general population.”
Children with cancer or other illnesses that weaken the immune system, for example, could have been included in the sample. “Normally, kids don’t get blood drawn for routine medical treatment unless they have a cause,” Dr. Iwasaki explained.
According to Deepta Bhattacharya, an immunologist at the University of Arizona studies relying on blood samples at clinics or by recruiting volunteers often overstate the number of persons affected.
“If you don’t do a random sample carefully enough, the seroprevalence numbers can get very bizarre,” he warned.
Scientists investigating blood donations in Manaus, Brazil, projected that 76 percent of the population had been exposed to the virus by October 2020, perhaps establishing herd immunity. That assumption proved to be completely incorrect: most of Brazil, including Manaus, had a long and fatal wave of diseases this year, with over 4,000 people dying each day at its peak.
Randomly sampling households is the best technique to estimate “seroprevalence” — the percentage of persons with antibodies to the virus. However, this is time-consuming and labor-intensive. And persuading huge groups of families to get blood drawn from healthy children is unlikely to succeed.
Because many children remained at home during the major outbreaks, the percentage of children infected in America is likely to be lower than the C.D.C.’s estimate, according to Dr. Bhattacharya. The figure of 42 percent “doesn’t pass the sniff test.”
My child may have had Covid. Is it possible to find out before I agree to the vaccine?
If you don’t already have evidence of your child’s infection — for example, the result from a P.C.R. test — there is no reliable method to confirm it now. Symptoms of Covid are similar to those of other respiratory infections.
“Determining who got an infection and who did not will be tough,” Dr. Iwasaki stated.
It’s also risky to screen for antibodies after the fact. The tests may not detect antibodies in children, in addition to the danger of false positives. Many people never show signs of illness, and studies show that those who are asymptomatic or have very minor symptoms make considerably fewer antibodies than those who are severely unwell.
“I’m not certain that serological testing can reliably identify those who have already been exposed,” Dr. Hensley added. “I don’t believe we’ve arrived at that stage yet.”
My child had Covid, Is the vaccination still necessary?
Experts advise against skipping vaccinations. Many issues about the strength and endurance of immunity in children remain unresolved.
Dr. Peter Chin-Hong, an infectious disease expert at the University of California, San Francisco, said, “There are too many unknowns on it, whereas the vaccination is known.” “I wouldn’t put all my eggs in the previous infection’s natural immunity basket,” says the researcher.
Natural infection immunity, like that acquired by vaccines, can wane with time, leaving children vulnerable to reinfection. “I’m curious as to when that infection occurred,” Dr. Chin-Hong stated. “If that had been a year or two ago, I would have been concerned about losing immunity.”
Natural immunity in adults “seems to be holding up nicely,” according to Dr. Bhattacharya.
However, it’s unclear if the protection shown in adults extends to children, partly because most children’s symptoms are milder than adults’, and they may not have established a full-throttled fight against the virus.
Children’s natural immunity may not be able to withstand variations. Several trials have indicated that giving a previously infected adult just one dose of the vaccine will boost protection, especially against variations like Beta and Delta.
“I believe that will also be the case with children,” Dr. Hensley stated.
Vaccination should also reduce the risk of a reinfected youngster spreading the virus to others who could become really ill. “The repercussions of having someone in your household who is particularly susceptible are pretty bad,” Dr. Bhattacharya said.
I’m worried about side effects. Is the vaccine safe?
So far, the research suggests that immunizations are significantly safer than a Covid infection, even in children.
Although the immunizations have been linked to a small but significant risk of myocarditis, or heart inflammation, in young men, the symptoms have mostly gone away. Covid is far more likely to cause myocarditis and a more severe form of it at that.
Dr. Hensley stated, “At the end of the day, acquiring immunity through infection is risky business.”
Over 8,300 children aged 5 to 11 were hospitalized during the epidemic, with roughly one-third of them confined to intensive care units, according to F.D.A. advisors. This age group has lost at least 94 children. Some people experience symptoms for weeks or months after the infection has cleared up.
According to Dr. Hensley, federal agencies are continuing to collect safety information regarding the vaccines and will be alerted to any major adverse effects that emerge.
There may be another option for children who have a history of heart disease or who do not respond to the immunization due to certain medical issues. Some businesses are working on long-acting antibody medicines that can reduce the risk of infection greatly.
“That’s the wave of the future,” Dr. Chin-Hong said of AstraZeneca’s antibody cocktail, which might protect recipients for up to a year.