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Is there a timeline for vaccinations for children? Do the “herd immunity” projections include children?

Biology/Immunity Families Vaccines

A: Trials for children 12+ are currently in progress for both the Moderna (ages 12-17; still enrolling!) and Pfizer (ages 12-15; done enrolling!) vaccines with the most optimistic timeline for vaccine approval in kids 12+ by the start of the 2021 school year.

Children will need to be vaccinated for us to achieve herd immunity, but getting the majority of adults vaccinated while approval of the vaccine in kids is pending will still have a large impact on reducing SARS-CoV-2 transmission, morbidity, and mortality.

Why do current trials only include kids aged 12+ years and what is the timeline for trials in kids aged < 12 years?

Vaccines are typically tested incrementally among younger and younger age groups to assure factors like dose and timing are tailored appropriately to children (and their unique immune systems) to maximize safety and efficacy in this population. Once the Pfizer and Moderna vaccines are approved in older kids (12+), trials will start for younger kids (most likely kids aged 5-11 years will be next). In addition to the two trials being run by Pfizer and Moderna, AstraZeneca which has already approved a vaccine for use in adults in the U.K, plans to start trials in children ages 5-18 in the coming months. In addition, results from the Johnson & Johnson/Jannsen phase 3 trials in adults are expected to be released soon and they are in discussions about including kids in their development plans. Given trials for kids younger than 12 years won’t begin until safety and efficacy are evaluated in kids 12+, it will likely be sometime in 2022 before a vaccine is approved for kids aged 5-11 years and 2022 or beyond in those even younger.

How will we reach herd immunity if we are waiting on kids to be able to get vaccinated?

Kids make up about 25% of the U.S. population and the proportion of the total population that will need to be vaccinated to reach herd immunity is between 70-90%, so kids will need to be vaccinated to achieve this goal. In addition, while rare for children to suffer complications from COVID-19, a small percent (very small < 0.01 percent) have developed a condition called multisystem inflammatory syndrome, or MIS-C, which while treatable, often requires hospitalization and some have died (about the same number of children that typically die from influenza each year). We also don’t yet know what the long-term consequences of COVID-19 will be for children. For these reasons, beyond helping us reach herd immunity for the entire population, vaccinating children against this disease is desirable.

Kids aged 16-17 years will the first in line among children to be vaccinated, as they were included in the emergency use authorization for the Pfizer vaccine issued in December, but unless they qualify based on having an underlying health condition that puts them at high risk of COVID-19 complications, they will probably be in one of the last groups for whom the vaccine will be made available this spring/summer. Next up will likely be kids age 12-17, starting as early as Fall 2021. After that, we can anticipate vaccination for kids 5-11, likely in spring 2022 at the earliest and sometime after that, kids aged 0-5 years. All together kids aged 5-17 years make up ~17.5% of the U.S. population, and kids aged 0-5 years about ~6.5%. So luckily, even before children are vaccinated, as the number of adults (constituting the other ~76.0% of the U.S. population) that are vaccinated increases this will make a huge impact on protecting individuals and reducing hospitalizations and deaths, as adults are most likely to experience these outcomes.

Importantly, even if the ultimate goal of herd immunity is a little ways off due to the extended timeline for the vaccine being available for kids, getting shots in arms of adults as fast as possible will help put the more immediate goals of reducing severity of COVID-19 at the individual level and preventing outbreaks in high risk settings at our fingertips that much sooner.
Overall, to reach herd immunity as quickly and safely as possible we should not only continue to #StaySMART, but when presented with the opportunity, use *all* our SMARTS-Space, Masks, Air, Restrict, Time….and SHOTS!! Adults now and kids soon!

Recent Atlantic article discussing similar questions

Answers to FAQ about vaccines in kids from Children’s Hospital in Boston

Our previous post about vaccine for kids

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