Vaccines were announced as a key measure to slow the COVID-19 pandemic and ended one day. Every day, millions of American adults are given one of the approved vaccines that have been shown to be highly effective in preventing serious illnesses that could otherwise lead to hospitalizations and death. In the US, most people over 65 are now fully vaccinated to protect the most vulnerable in our population.
As an infectious disease specialist, my answers to the following questions are based on what we know so far about infections and vaccines in children and adolescents. We must continue to fill in the gaps as the research finishes and our understanding evolves.
What do we know about how COVID-19 affects children and adolescents?
Most COVID-19 infections in children are mild or cause no obvious symptoms. A small percentage of infected children
- develop a serious inflammatory condition called MIS-C in the two to six weeks after contracting COVID-19. This can occur even in children who have mild or no symptoms.
- get very sick and need hospitalization or intensive care.
Over 400 children have died from COVID-19 infection. That's more than the number of child deaths during the deadliest flu season in two decades.
Vaccinating children to prevent these results is one of the most important reasons for vaccinating studies in children. In addition, vaccinating children will be critical to achieving a population-wide level of immunity – herd immunity – sufficient to slow the emergence of dangerous variants and end the pandemic.
What do we know so far about COVID-19 vaccines in teenagers?
- The Pfizer / BioNTech vaccine is approved for use in people aged 16 and over.
- Moderna and Johnson & Johnson vaccines are approved for use in people aged 18 and over.
- These approvals were based on data from participants of this age in randomized, placebo-controlled studies that demonstrated the safety and effectiveness of these vaccines. Efficacy measures how well a vaccine works under the controlled circumstances of a study. Effectiveness is how well a vaccine works outside of a study when people in the community are receiving it.
As states expand eligibility for COVID-19 vaccines, teenagers 16 and older can get the vaccine from the same sources that adults have previously had access to. The vaccination centers available may vary depending on the state and the location where you receive medical care. Check the searchable card on the VaccineFinder or your state health authority.
Vaccine research that has been or is currently being carried out includes the following:
- Pfizer / BioNTech completed a study in 12 to 15 year olds. This study used the same dose and schedule of vaccine as in adults: two doses three weeks apart. The company announced in a press release that the vaccine was safe, well tolerated, produced strong antibody responses, and was 100% effective in preventing mild to severe infection in this age group. The FDA is reviewing the data and will consider approving this vaccine for use in this age group. If all goes well, we can expect this vaccine to be available to 12-15 year olds in the coming months.
- Moderna completed enrolling 12-17 year olds in a similar study using the same dose and schedule as adults: two doses four weeks apart. Data from this study are expected in the next few months.
- Johnson & Johnson has started a study of its vaccine for a small number of 16-17 year olds. If the vaccine proves safe and effective in this age group, the study will continue in 12 to 15 year olds.
What About COVID-19 Vaccine Trials For Younger Children?
- Pfizer / BioNTech and Moderna both started studies in children aged 6 months to 11 years.
- These studies each begin by testing smaller doses than older children, adolescents, and adults. This allows researchers to determine which dose is well tolerated and still produces strong antibody results in younger children.
- Once the dose is established, larger numbers of children in these age groups will be enrolled in placebo-controlled studies to evaluate the effectiveness of these vaccines.
All of these steps will take some time to complete without compromising security. The earliest vaccines for younger children will likely be available in late 2021 or perhaps early 2022.
What is still not known about COVID-19 vaccines in children and adolescents?
- How long the vaccine-induced immunity to COVID-19 infection persists in children needs to be monitored over time. The results of such studies will help experts decide whether children will need boosters for COVID-19 vaccines in the future.
- Researchers also need to investigate whether COVID-19 vaccines can be combined with other vaccines that children routinely receive. Currently, the CDC recommends that no further vaccines be given within 14 days of a COVID-19 vaccine. This applies to people of all ages.
- Researchers need to evaluate the effects of these vaccines on protecting children from infection with COVID-19 variants. However, biologically there is no reason to expect differences in vaccine coverage of variants in adults versus children.