Why Children Will Not Be Included In The First Wave Of Covid-19 Vaccines

Clinical trials for a Covid-19 vaccine for children are only just beginning. Most kids will not be vaccinated until later in 2021


As encouraging news emerges about a possible vaccine against Covid-19, the natural question becomes “When will I get mine?”

There is still no definite date that vaccines will be widely available, but one demographic can bet on not being immunized during the initial rollout of Covid-19 vaccines — kids.

Drug company Moderna announced that they will begin to recruit for clinical trials looking at the efficacy of their mRNA-1273 vaccine in adolescents. With promising efficacy and safety data emerging, this begs the question — why the delay in testing efficacy in children?

How Vaccines For Children Are Made

Many feel that children are among the most vulnerable populations in society. Many social and medical protections are first extended to safeguard children before adults. But the opposite is true when it comes to experimental drugs and therapies including vaccines.

Drug companies are required to first test the safety and efficacy of a vaccine on adults before testing on children. Vaccine makers would only be able to initiate clinical trials on children once long-term safety data was available on adults. In the case of a Covid-19 vaccine, that means right now.

Phased clinical trials are a lengthy and intentionally controlled process. Testing begins in the laboratory by establishing a mechanism, then in animal models and finally in three phases of human clinical trials with increasing participant cohort sizes.

A Different Immune System

Children, particularly infants and toddlers have immune systems that behave differently from adults. For those within the first year of life, the sophisticated system of antibody production — what is known as adaptive immunity — has really only just begun. Up until then, children are protected by a vigorous innate immune system, and what antibodies are pass from mother to child in the breast milk.

Infant and children immune systems are highly reactive. Their immune systems are being exposed to many of the pathogens and environmental factors in our world for the first time. Juvenile immune systems have not undergone the rigorous training that an adule immune system has. For this reason, you cannot assume a child will react to a vaccine in the same way as an adult.

Clinical trials of vaccines for children involve not only testing the efficacy and safety of the product, but validating that the dosing and regiment for the vaccine are appropriate. Often, vaccines need to be administered at different doses depending on peoples age. For example, people over 65 years old are recommended to get a double dose of the flu virus to compensate for thier aging immune system.

When Will Kids Be Vaccinated?

While there is no definitive timeline for vaccinating children against Covid-19, many feel that a widespread vaccine campaign for kids will lag significantly behind adults. Some skeptics are worried that a Covid-19 vaccine will not be available to kids before the start of the 2021 school year.

There still remains some debate as to the role that children are playing in the spread of Covid-19. Schools were thought to be hotspots of transmission of the virus initially, but some data came out that went against that belief. This prompted waves of school closures and reopenings.

A study published in the Journal of Pediatrics seemed to indicate that children do play a significant role in the transmission of Covid-19 after all. Because social distancing and mask wearing are major challenges in the school setting, children remain an important population for vaccination.

Considering that that leading candidates for vaccines have already been validated as safe in adult clinical trials, this should ease the path to testing the vaccine in children. Despite that, a Covid-19 vaccine for children is still months away.

The delay in validating a Covid-19 vaccine in children is intentional, and an important step in creating a vaccine that is safe for all groups of people.

Medical student, molecular biologist and educator. I write about science and medicine.

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