COVID Vaccines For Children Under 5

Does my child actually need the vaccine?

Yes. There is a tremendous burden of disease in this age group. Thankfully the rate of severe disease is lower compared to adults, but this is an inherently flawed comparison because kids don’t die as often as adults. Since the beginning of the pandemic, 442 children aged 0-4 years old have died from COVID-19. If we compare to other vaccine preventable diseases among children, deaths due to COVID19 are highest. We cannot become numb to these deaths.
In terms of hospitalization, children, and specifically those under age 5, did not fare well during our first Omicron wave. According to the CDC, children under 5 had the highest rate of hospitalizations compared to other pediatric groups. Among children hospitalized, 1 in 4 ended up in the ICU.
The rate of COVID19 hospitalization was particularly high in October 2021-April 2022 compared to previous flu years and compared to COVID19 hospitalizations the prior year (October 2020-September 2021).
Severe disease is not the only outcome of SARS-CoV-2:

Long COVID19 does occur among kids, and vaccines reduce the burden of long COVID by 15-50%.

We parents know that masking and social distancing very young kids can be nearly impossible. The layers of protection we can employ are less than optimal.

We have frequent, unexpected disruptions in care and schooling of children that contribute to the daily burden of COVID. While not perfect, vaccines will help reduce infections and transmission, inching us closer to less family disruptions.

What if my child was recently infected with COVID19?

We are still trying to understand the durability and breadth of infection-induced protection, especially as Omicron continues to mutate. Very recent scientific evidence shows that 32% of children failed to make antibodies against SARS-CoV-2 after confirmed infection and had mediocre T-cell responses.

This isn’t surprising. Omicron-induced immunity among unvaccinated people does not protect against other variants of concern. In addition, the quality of response (i.e., memory B-cells and T-cells) is relative to the severity of infection. If a child had a mild infection (which many do), then they likely had a lower viral dose and that secondary protection is less likely. This underscores the importance of vaccinating kids regardless of previous infection.
Vaccines clearly improve protection; antibody concentrations after a Moderna shot significantly increased after vaccination among those who were not infected and those who were previously infected.
Vaccine + infection is called “hybrid immunity” and more than 20 studies among adults have shown it works fantastically due to complementary and broad protection: vaccine immunity targets the spike protein, and infection-induced immunity targets the whole virus. This doesn’t mean you should purposefully get your child COVID19, but we need to recognize this as a viable path to protection.

Are the vaccines for children under 5 safe?

Yes. During the clinical trials, side effects were minimal:

For 6–23 month-olds, irritability (65% Moderna vs. 44% Pfizer) and drowsiness (40% Moderna vs. 20% Pfizer) were most common.

For 2–5 year-olds, pain at injection site were most common (60-70% Moderna vs. 27% Pfizer), followed by fatigue.
For Moderna, 1 in 4 experienced a fever. Side effects were more common after Dose 2. For Pfizer, 1 in 20 experienced a fever, and side effects for Dose 3 were similar to Dose 2. The higher rate of Moderna side effects is due to the higher dosage of RNA.

No myocarditis cases were reported in either clinical trial. This is great but expected news. The clinical trials were not nearly large enough to capture such a rare event. Data from 5–11-year-olds show no myocarditis safety signal unlike 12+ year-old boys. The leading hypothesis is that myocarditis among teenagers is caused by a combination of increased hormones and genetics. This is a hint that we may not see myocarditis as an issue for our very youngest kids, but data will be closely followed.

Are the vaccines effective?

Yes. The FDA required Moderna and Pfizer to prove immunobridging. This is a process that compares antibodies among this youngest age group to another age group (in this case, 16–25 year-olds) in which the efficacy of a vaccine is already established. We already know this vaccine works well; we just need to be sure the dosage works for kids.

Clinical trials found that antibody numbers were comparable to the older age group. In other words, the 2 doses of Moderna and 3 doses of Pfizer worked.

Pfizer and Moderna also reported efficacy against COVID19 disease. Remember that the two aren’t on the same playing field because of different doses:

Moderna reported 37-46% efficacy against disease for 2–5 year-olds after 2 doses. And 31-51% for 6–23 month-olds after 2 doses.

Pfizer reported 80.3% efficacy after 3 doses.

We have a hard choice. Which vaccine should my kids get?
 You cannot make a wrong decision. Either vaccine is better than nothing, and both help with severe disease and death.

Katelyn Jetelina, MPH, PhD, is an epidemiologist, founder of Your Local Epidemiologist [newsletter], and Adjunct Professor at UTHealth School of Public Health. She was an observer at the June 14th meeting of the VRBPAC scientific advisory committee that voted 21-0 to recommend that the FDA authorize the COVID vaccines for children less than 5 years old.
Published: 7/2/22

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