get those vaccinations

Third dose booster offers many benefits for children

A few weeks ago, the FDA amended the emergency use authorization of the Pfizer-BioNTech mRNA vaccine for ages 5 to 11 to include a booster dose. The authorization stated that the third dose be given at least five months after finishing the two-dose primary series. The CDC then quickly recommended the booster for this age group. There are many benefits for children receiving this additional dose.

Like many common vaccines, the mRNA COVID-19 vaccines should have been a three-dose series. The first two injections prime the immune system, and the third boosts it to provide a higher antibody response. In 5 to 11 year olds, the booster more than doubles the antibody levels found following the second dose. Additionally, boosting has been shown in other age groups to further improve the antibodies so that they better bind the virus and provide more protection against variants.

Some wonder if it makes strategic sense to hold the booster until it is closer in time to visiting the grandparents, summer camp or the start of school. Although good in theory, COVID-19 cases are up even with the under-reporting of positive home testing results. With the current wave rising, now is the best time to boost. Additionally, if another shot is needed this winter, then receiving the third dose now will ensure enough time for a dose before the holidays. 

The exception to boosting right now is a recent COVID-19 illness; then it is reasonable to wait three months. Unfortunately, people can get COVID-19 just four months following infection. Waiting three months may strengthen the immune response to the vaccine. 

Another benefit is that different quarantine rules apply to those who are boosted. When a person who is not boosted is exposed to COVID, they are to quarantine for five full days. If they remain symptom-free, they can leave quarantine but should continue to monitor for symptoms for another five days.  Exposed individuals who are up to date (boosted) do not need to quarantine unless they develop symptoms.

Side effects from a booster dose are like those experienced with the primary series. The most common is a sore arm, followed by feeling tired and having a headache. Less common side effects are swollen lymph nodes in the neck or under the arm which usually resolve in less than a week. 

Less than a third of 5 to 11 year olds have received the recommended two doses of the mRNA vaccine which is much lower than other eligible age groups. Unvaccinated children are more likely to get infected and twice as likely to be hospitalized than those who are vaccinated. Sadly, 189 children in this age group have died from COVID-19.

The highly anticipated FDA and CDC discussions about vaccinating children 6 months and older against COVID-19 will occur later this month. We expect that the result will be good news for protecting this age group.

Megan Berman
Richard Rupp
Vaccine Smarts is written by Sealy Institute for Vaccine Sciences faculty members Drs. Megan Berman, an associate professor of internal medicine, and Richard Rupp, a professor of pediatrics at the University of Texas Medical Branch. For questions about vaccines, email