Vaccinating Our Children Under 5: Moderna or Pfizer?
Author: Ryan Hassan, M.D., Boost Oregon's medical director and pediatrician working at Oregon Pediatrics in Happy Valley.
The FDA has now approved the use COVID vaccines for children 6 months to 5 years of age, and many of us are eager to get our children and communities this extra layer of protection. Here I will provide a brief overview of the two approved vaccines for this age group: the Moderna mRNA vaccine and the Pfizer mRNA vaccine.
Most importantly, both of these vaccine series have been found safe and effective in children in this age group in phase 3 trials, which is why the FDA approved their use through the Emergency Use Authorization.
Moderna
The Moderna trial was conducted from December 2021 through February 2022, and included 6400 children between 6 months and 5 years old. The trial studied the efficacy of a 2 dose series given 28 days apart, and followed vaccinated children for 2.5 months after vaccination (all vaccine reactions in the history of vaccines have occurred within 2 months of vaccination). The trial found that children 6 to 23 months old were 50.6% less likely to get sick with the Omicron strain of COVID, and those 2 to 5 years old were 36.5% less likely to get sick.
Side effects were similar to those seen in adults, and included pain at the injection site, fatigue, headache, irritability, and sleepiness. Fevers were less common.
Pfizer
The Pfizer trial was conducted from June 2021 through April 2022, and looked at the efficacy of a 3 dose series, with doses 1 and 2 separated by 21 days, and doses 2 and 3 separated by 8 weeks. The study included 4,488 children aged 6 months to 4 years old who received the first two doses of vaccine or placebo for the study, and 1,456 children who completed the study for the full 3 dose series. The data showed that children 6 to 23 months old were 75.5% less likely to get sick with the Omicron strain of COVID after completing the 3 dose series, and those 2 to 4 years old were 82.3% less likely to get sick. These numbers, though, could be far off from the actual effectiveness of the vaccine; because they are based on just 10 total COVID-19 infections; 3 in the vaccine group and 7 in the placebo group.
Side effects in this trial were also similar to those seen in adults.
Which to choose?
Overall this data tells us that the Moderna vaccine provides protection more quickly, with children getting up to 50% protection after just 2 doses; whereas Pfizer provides very little immunity until after the third dose, which takes about 3 months to complete. We also don’t know with any certainty whether the actual protection offered by Pfizer is higher, lower, or similar to that offered by the Moderna series; because of the limited numbers of cases in the trial. Also, it is expected that a 3rd dose or booster dose of Moderna will be approved in the near future, which may lead to even more immune protection.
For these reasons, some of my colleagues and other healthcare professionals prefer the Moderna vaccine over the Pfizer vaccine. If getting your child protected more quickly is important to you, it may make sense to get the Moderna vaccine. That said, I got my 14 month old baby vaccinated with the Pfizer vaccine the Saturday after it was approved; because it was the most readily available for me, and I am happy with that choice. I do not have a strong preference one way or another, as both vaccines will provide good protection against COVID infection and have low risk for side effects, and if Moderna had been the more convenient option for our family, I would’ve gotten that vaccine for my baby instead. My baby had no side effects after her vaccine and I am happy to be able to finally provide some additional protection for her, and to better protect our family, friends, neighbors, and community at large, by helping to slow the spread of the virus that’s killed over a million Americans.
My recommendation for all parents is to get their children over 6 months old vaccinated with whichever vaccine is available to them as quickly as they can. If you still have questions about the vaccine, please speak with your healthcare provider, or reach out to us here at BoostOregon.org.
Reference:
Recommendations for Pfizer-BioNTech and Moderna COVID-19 Vaccine Primary Series in Children 6 Months through 5 Years Old. Clinician Outreach and Communication Activity (COCA) Call Wednesday, June 22, 2022 COVID-19 Updates: What Clinicians Need to Know About MIS-C (cdc.gov)
Feature Article: Long-term Side Effects of COVID-19 Vaccine? What We Know. Children's Hospital of Philadelphia (CHOP) Vaccine Education Center. https://www.chop.edu/news/long-term-side-effects-covid-19-vaccine
