The Perfect Enemy | Why to Get Your Young Kids Vaccinated Against COVID-19 | Time
March 29, 2024

Everyone in the U.S. 6 months or older is now eligible to get a COVID-19 vaccine, after the U.S. Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC) authorized the shots in June for very young children, from 6 months to 5 years old. They’re the last age demographic in the U.S. to become eligible to get vaccinated during the pandemic.

Despite the regulatory green light, many parents of young children are wondering whether it’s even necessary to get their kids vaccinated at this point in the pandemic, since infections have become so common and, in general, the virus causes relatively mild symptoms in most kids.

But while studies that follow kids for longer periods of time are ongoing, the current evidence points to more benefits than risks of the vaccines for little ones. Below are some common concerns among parents, along with the latest consensus from experts about what the science shows so far.

Hospitalizations and deaths of the youngest kids are on the rise

COVID-19 does tend to cause milder disease in children compared to adults. But Omicron has raised the stakes in this population.

Data from CDC’s COVID-19 Data Tracker show that during the peak of the initial Omicron wave, in January to February 2022, rates of hospitalization for infants and toddlers under 4 years old were more than four times that of the rates for children ages 5 to 17 years. Part of that, public health experts say, could be attributed to the fact that the younger children were not yet eligible to be vaccinated, while the older children were. The rates strongly suggest that children of any age who are not vaccinated and get COVID-19 could develop severe enough disease to need hospitalization.

Real-world data show COVID-19 vaccination is safe for kids

Some parents are concerned that the mRNA vaccines haven’t been tested for long enough in children. But the research submitted to the FDA by Moderna and Pfizer-BioNTech, the two companies that have received pediatric authorization for COVID-19 vaccines, is pretty thorough. Moderna’s study involves nearly 1,600 children from 6 months to 5 years old, while Pfizer-BioNTech’s includes more than 4,500 children from 6 months to 4 years old; some of those children served as controls and received placebo shots, while others received the actual vaccine doses.

In both cases, the companies followed up with the kids in the studies about two months after they received the second of their two-dose primary series of vaccines. And in both cases, the rates of adverse reactions were similar to those observed for older children and adults, including from real-world data collected from hundreds of millions of adolescents and adults who have been vaccinated with the shots already.

None of the young children who were vaccinated in either company’s studies developed severe adverse reactions. The most concerning side effect that has been documented in older children, mostly adolescents, involves inflammation of heart tissue; it’s extremely rare even in that age group, and so far hasn’t been seen at all among younger vaccinated children.

The CDC’s system for monitoring side effects and reactions to vaccines will continue to comb through data to pick up any signs of increases in known side effects, or reports of new ones. And the vaccine manufacturers will also continue to study the safety and effectiveness of their shots in young children.

Kids’ shots are likely about as effective against Omicron as adult vaccines

Back in 2020, the mRNA vaccines generated stunning efficacy numbers upwards of 90%. But efficacy rates for the youngest children’s shots aren’t as impressive. Why not? A different version of SARS-CoV-2 was circulating when the shots were first developed. Both vaccines were developed to target the original virus strain, which is no longer responsible for the majority of COVID-19 cases. That strain has been replaced by a series of variants, the latest of which is Omicron and Omicron’s subvariants, BA.4 and BA.5, which now account for half of infections in the U.S.

In Moderna and Pfizer-BioNTech’s studies of younger children, participants were given the same version of the vaccine—targeting the original virus—at smaller doses. But because these studies occurred more recently, during the first Omicron wave this past winter, the efficacy of the vaccines in this age group, as measured by antibodies that can neutralize the virus, reflect immunity against Omicron, not the original strain, which accounts for the drop. The antibodies that were tested, however, continue to provide protection against serious COVID-19 disease, and make up only one part of the immune response generated by the vaccines.

Even though they can’t completely stop infection, vaccines slash the risk of bad outcomes for kids

People who are vaccinated and boosted can (and do) still get COVID-19. But that’s no reason not to get the shots. No vaccine, including those targeting childhood diseases such as measles, is 100% effective. Vaccines are primarily designed to protect people from getting severely ill from a given disease, and not to ensure that they don’t get infected in the first place.

The infections occurring among vaccinated adults are due to the Omicron variant and its subvariants. Adults are immunized with vaccines that targeted the original virus; the strength of that immunity has dropped as new variants have emerged—especially against Omicron.

That said, the original vaccines are still effective at generating a broad immune response to counter the worst impacts of all of SARS-CoV-2’s variants, from Alpha to Omicron. In other words, even if vaccinated adults are getting infected, the shots are still largely protecting them from getting seriously ill with COVID-19 and needing to be hospitalized.

Adults who have been vaccinated and boosted have generally reported milder symptoms and milder disease than people who are unvaccinated. Experts say the same appears to be true for children as well.

Getting Omicron is safer if young kids are vaccinated

Studies have documented Long COVID, a constellation of lingering symptoms involving the brain, heart, and other body systems that could represent lasting health effects of an infection—but the true extent of Long COVID remains unknown. The data on Long COVID are even less complete for children, so most public health experts believe that the preventative benefits of the SARS-CoV-2 vaccines outweigh any potential risks. In adults, data show that getting vaccinated reduces the risk of Long COVID. Studies are starting to show that people who get infected after being vaccinated also tend to experience milder symptoms and less severe disease compared to unvaccinated people who get infected.

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