- Clinical trials involving children have begun for COVID-19 vaccines.
- Experts say this is important because children are 20 percent of the U.S. population.
- They note that it's difficult to reach herd immunity without vaccinating children.
With clinical trials planned or underway, children might be able to start receiving COVID-19 vaccines by this fall.
Experts say that round of vaccinations could be the final step to controlling the COVID-19 pandemic.
As it stands, about 15 percent of people in the United States have received at least one dose of the COVID-19 vaccine.
Right now, the Moderna vaccine and recently approved Johnson & Johnson vaccine are only available for adults ages 18 and older. The Pfizer-BioNTech vaccine is approved for people ages 16 and older.
That means that nearly 20 percent of the U.S. population isn't currently eligible to receive the vaccine.
Unvaccinated children can potentially transmit the virus
While those 20 percent of younger people remain unvaccinated, that means they have the potential to continue transmitting the coronavirus.
“Children can spread the virus to adults, and vaccinating children will be an essential element in decreasing infection rates,” said Ann Muñana, DNP, a master instructor at Chamberlain University and a member of the Chicago Department of Public Health COVID Vaccine Scientific Workgroup.
How long children can transmit the virus after being exposed is unknown, but the risk remains.
“Probably this period is similar to the time period in adults,” Dr. Robert Amler, the dean of the School of Health Sciences and Practice Building at New York Medical College and a former chief medical officer at the Centers for Disease Control and Prevention (CDC) Agency for Toxic Substances and Disease Registry, told Healthline.
“How much this contributes to spreading the virus in different communities is not well known,” he said.
Kids might be necessary to achieve herd immunity
Since children with the virus could keep the flames of COVID-19 alive in the community, experts say we may need to include vaccinating children to reach herd immunity.
What percentage of that younger population needs to be vaccinated is currently unknown.
“The estimates of what constitutes herd immunity for COVID-19 vary quite a bit. I’ve seen anywhere between 60 to 90 percent,” said Nichole Cumby, PhD, an assistant professor of microbiology at the University of Medicine and Health Services' St. Kitts campus in the Caribbean.
“However, if it is closer to the upper end of that threshold — which is likely given the emergence of the new variants, which are able to spread more easily — then children under 16 will likely need to be vaccinated to get to the 90 percent vaccinated mark,” she said.
Then there's the reality that not every adult will get vaccinated, either by choice or because of health complications.
“For a few, they have allergies that prevent them from receiving the current vaccine. Others are electing not to for a variety of reasons,” Cumby told Healthline.
“Since we are unlikely to see all adults getting vaccinated, vaccinating children becomes more important for reaching the critical threshold for herd immunity,” she said.
Why separate trials are necessary
Current active clinical trials involve children ages 12 and up with plans to test younger children if these trials go well.
“The most ethical way to do these studies is to start with older children and then move on to younger children gradually,” said Johan C. Bester, MBChB, PhD, MPhil, the director of bioethics at the University of Nevada Las Vegas School of Medicine.
“There must always be a consideration of the interests of the children that are involved. It is important to have extra safeguards in place when doing research involving children to be sure that the interests of children are protected,” he said.
While similar to adults in some ways, children’s biologies and, in particular, immune systems can differ significantly from those of adults.
Look no further than the lower rates of COVID-19 among children — they’re half as likely to get it as adults — as well as child-specific reactions to the disease, such as multisystem inflammatory syndrome.
“It’s important to recognize that children aren’t merely little adults. Therefore, we need to do the hard work of evaluating the vaccine in clinical studies so that we can ensure the right dose and the right frequency of immunization,” said Dr. C. Buddy Creech, MPH, the director of the Vanderbilt Vaccine Research Program at Vanderbilt University Medical Center in Tennessee.
Protecting the future
The bottom line, most experts say, is the more people vaccinated, the better — regardless of their age.
“We are just beginning to learn about what might be the long-term implications of having had COVID, and as time goes by, years go by, we will likely see the long-term impact of the infection,” Muñana told Healthline.
“We don’t know how a child, or an adult for that matter, who has recovered from COVID might years later experience health issues. For example, respiratory or neurological conditions. Therefore, it is important that we make sure to vaccinate as many as possible, including children, who meet the eligibility criteria for vaccination,” she said.