Scientists are still gathering data to better understand how COVID-19 vaccines last in both young people and older adults.

Clinical trials of the Pfizer vaccine suggest the shot is 90.7% effective in preventing COVID-19 in children ages 5 through 11, with no serious side effects detected in the ongoing study of over 3,000 children from multiple countries. These results are based on a lower dose vaccine for children between 5 to 11 years old, where two 10 µg doses are given compared to the two 30 µg doses given to people over 12 years old. Kids aged 5-11 produce a similar antibody response to adults, data shows.

For people over 16, current data suggests that COVID-19 vaccine protection can last at least 6 to 8 months. This is based on studies conducted by Moderna, Pfizer and BioNTech, and Johnson & Johnson as well as other pre-print and peer-reviewed research publications. Since clinical trials have found that the vaccines work similarly in adults and children aged 5-11, it is possible that vaccine-induced immunity may last for a similar amount of time in those groups.

In some contexts, booster shots are now recommended for higher-risk people who got their first dose or set of doses over 6 months ago. It is not yet known if or when booster shots will be recommended for younger populations. Many health experts say the priority remains getting as many people as possible their first COVID-19 vaccine shots.

Even though protection from many types of vaccines can wane over time, especially as new variants of viruses emerge, approved COVID-19 vaccines have continued to protect people against the most severe health consequences of COVID-19 for many months and breakthrough infections remain relatively uncommon.

Although the majority of severe COVID-19 cases leading to hospitalization and death has been in older adults, vaccine protection for children is important to reduce disease transmission in households and communities as well as to protect the health of children during school, sport, and socialization. While hospitalization and death from COVID-19 is less common in children, severe outcomes are unfortunately still possible: 691 deaths have been reported in the U.S. among youth under 18, with 146 deaths occurring among youth 5 through 11, as of October 17, 2021. Data continues to be gathered on the long-term health consequences of COVID-19 in children. 

The Pfizer-BioNTech COVID-19 vaccine, also known as Comirnaty, for children between 5 to 11 years old is now approved by the U.S. Food and Drug Administration (FDA) and recommended by the U.S. Centers for Disease Control and Prevention (CDC). The vaccine has been found to be safe and effective through rigorous clinical trials and regulatory review processes. Families and caretakers of children with questions about this vaccine can consult healthcare providers and check verified sources of health information. For example, the Mayo Clinic website has a section of frequently asked questions (FAQs) on the COVID-19 vaccine for young people and the U.S. CDC website provides information on how to prepare children and teens for COVID-19 vaccination, eligibility and where children can get vaccinated, and what to expect in terms of possible side effects.

According to a report by the American Academy of Pediatrics, nearly 6.4 million children in the U.S. have tested positive for COVID-19 as of October 28, 2021. Children between 5 to 11 years old make up an estimated 39% of COVID-19 cases among people under 18 years old. The approval of the Pfizer-BioNTech vaccine for children ages 5 through 11 in the U.S. is expected to impact 28 million children, with vaccines being provided free of charge by the federal government regardless of immigration or health insurance status. Pfizer and BioNTech also announced that preliminary data should become available in the fourth quarter of 2021 for two younger age cohorts in their Phase 2/3 clinical trial of vaccines for children: between 2 to 5 years old and between 6 months to 2 years old.