COVID-19 vaccines for adolescents and children
SciLine reaches out to our network of scientific experts and poses commonly asked questions about newsworthy topics. Reporters can use these responses in news stories, with attribution to the expert.
What are Quotes from Experts?
May 11, 2021
Why are adolescents (12-17) and children (<12) grouped into their own clinical trials, separate from adults?
“From a biology standpoint, adolescents, defined as those between age 12-17, are very similar to adults. The FDA also provides regulatory guidance for clinical trials and includes 12-17 year olds together because of these similarities. Once we move into children younger than 12 years of age, we begin to see more variability in weight, pubertal status, and other factors that might influence responses to drugs and vaccines.” (Posted May 11, 2021)
“Children are not small adults. They may have either different side effects, requirements for different dosing, or different immune responses than adults. Therefore, most vaccine clinical development strategies include testing an experimental vaccine in young, healthy adults, before considering them in either older—potentially more frail—or younger individuals.” (Posted May 11, 2021)
“The initial clinical trials were conducted in the age groups where we saw the greatest risk of severe COVID-19 disease and virus transmission, to maximize immediate impact of the approved vaccines and streamline the management of these large trials. The trials for younger individuals were being planned and set up while the adult trials were ongoing, giving us the best ability to test the vaccines as efficiently as possible.” (Posted May 11, 2021)
“Vaccines and other investigational products are always evaluated first in adults, because children are considered to be a special and more vulnerable group. Safety must be established in adults first, and then the vaccine can be tested in younger and younger age groups, with safety checks along the way. The type of trial plan that does this is called ‘age de-escalating,’ and the major COVID vaccine manufacturers are conducting this type of trial program. In addition, dosage often has to be adjusted in younger age groups, so the current trials are also ‘dose-finding’ trials.” (Posted May 11, 2021)
Now that the Pfizer vaccine is approved for adolescents, what do we know about vaccine availability for this age group?
“In many areas across the US, we do not see a shortage of vaccine availability. In fact, in areas such as the southeastern US, we are doing all we can to use the vaccine doses already allocated. At this point in the pandemic, we have vaccinated the majority of those that are at the highest risk of COVID-19 complications; now is the time to ensure vaccination of those that may contribute to ongoing community spread of disease.” (Posted May 11, 2021)
“This should be happening quite rapidly in the US, where supplies of the Pfizer/BioNTech vaccine have been high and, sadly, demand has been dropping. This is not the case in Canada, which has also authorized the vaccine in adolescents, but where supplies are more limited.” (Posted May 11, 2021)
“There seems to be an adequate supply of vaccine currently. Unfortunately, this is partially due to recent slowdowns in adults in getting vaccinated against COVID-19. Hopefully as more people are recommended to receive COVID-19 vaccines, this will spur greater vaccine demand across all ages for which the vaccine is approved.” (Posted May 11, 2021)
“My understanding is that overall vaccine availability in the US is excellent. However, distribution to centers and to doctors’ offices that will administer the vaccine to this younger age group is still underway by the [Biden] administration.” (Posted May 11, 2021)
How important will it be to vaccinate adolescents and children in the efforts to reduce transmission of COVID-19?
“One common challenge in communicating the need for vaccination is that many have rightly identified themselves as low risk for COVID-19 complications. This is true—teenagers, by and large, are able to navigate COVID-19 without a great deal of difficulty. But we are vaccinating as many as we can not only to prevent complications in the individual, but also to provide protection to all in our community. This is a critical aspect of living in community with one another; there are times when we face something that we can only solve together. The pandemic is a prime example of this – we vaccinate to protect ourselves and to protect one another.” (Posted May 11, 2021)
“Including adolescents in our vaccine programs may well help in reducing onward transmission of COVID-19; it is less clear to what extent younger children—particularly those under 10—contribute to transmission, and therefore not clear that immunizing younger children will contribute significantly to herd immunity. This is a matter of debate, particularly given the limited vaccine supply and the devastating impact of the pandemic in many countries that so far have not had access to vaccine. It is helpful to note that countries like the UK and Israel have seen a dramatic impact of vaccination in their countries despite not having immunized any individual under the age of 16. This suggests that immunization of adolescents and children may not be absolutely necessary to reduce COVID-19 transmission and get a handle on the pandemic.” (Posted May 11, 2021)
“We have recently seen more transmission of COVID-19 among children, adolescents, and young adults. Right now, it is unclear if this is due to how people are coming together, emergence and wider spread of COVID-19 variants, or a greater recognition of disease in these younger groups. Regardless of the reason, it is important to protect the health of our children and adolescents, and vaccinating these groups not only helps them, but helps prevent the spread of the virus more widely across the population.” (Posted May 11, 2021)
“This is probably very important as well. We think of giving this vaccine to 12-15 year-olds first for the benefit to their own health, and second to the contribution it makes to stop spread to anyone who may be susceptible to COVID. Even though schools have not been a major source of outbreaks, there will always be potential to spread the virus in indoor group settings including schools until everyone is vaccinated.” (Posted May 11, 2021)
How do adolescents and children factor into efforts to achieve herd immunity?
“We do not yet know the exact number of immune individuals needed to stop this virus in its tracks. For some infections, such as measles, greater than 90% of the population must be immune to prevent measles from establishing a foothold. For other infections, as we get to 60%, 70%, or 80% we start to see substantial drops in disease activity. By vaccinating adolescents, in particular, we may be able to put enough pressure on the virus that we can drive down the rates even further.” (Posted May 11, 2021)
“Data from various studies suggest that adolescents likely contribute more to transmission than younger children. If this is true, then immunizing adolescents would be expected to have a greater impact on herd immunity than immunization of young children. At the same time, the success of vaccination programs in countries like Israel or the UK, where no one under 16 has been immunized, suggests that a dramatic impact of vaccination can be seen even without immunizing adolescents and younger children.” (Posted May 11, 2021)
“Leaving a large chunk of the population unvaccinated – nearly 19% of the US population is younger than 15 years of age – provides for many individuals who can be infected with, and spread, the virus that causes COVID-19. It will be very difficult to reach herd immunity if this many children and adolescents remain susceptible. High vaccine coverage across the population will be our best way to minimize the impact of COVID-19 moving forward.” (Posted May 11, 2021)
“With more than 70 million adolescents and children under the age of 18, there is a great opportunity to increase our overall population immunity to SARS-CoV-2. The term “herd immunity” has been kicked around a lot, and because it is imprecise many people favor using other terms now. We do know that the higher the level of immunity in the population, the less spread of virus there will be, and more importantly less disease and death. We don’t know if we will reach a level of immunity sufficient to stop all spread of the virus. This seems unlikely currently, especially with new variants and with the ongoing global pandemic. We may reach a time where a significant majority of Americans are immune but pockets of spreading infection continue among non-immune individuals and groups, with overall infection levels remaining low. We can hope for an even better situation with minimal spread in the US, but the virus has proven to be somewhat unpredictable.” (Posted May 11, 2021)
Are adolescents and children expected to experience side effects from the vaccine similar to those seen in adults?
“At this point, from the data that have been made available, it looks like adolescents experience the same types of side effects as adults – arm pain, achiness, fatigue, and headaches. These are short lived, and usually occur in the 1-2 days after vaccination. As we move into younger and younger children, we’ll be watching this very carefully so that we can provide parents with guidance on what to expect after vaccination.” (Posted May 11, 2021)
“This is a difficult question, given the relatively low numbers of adolescents and children who have received the vaccine so far in clinical trials. Authorization of the Pfizer vaccine by US FDA in 12–15-year-olds is a very positive sign that the side effect profile of the vaccine in this age group is reassuring. The FDA will of course want to see the data for young children when available as well. Side effects of various vaccines in children differ from those of older patients, which is one of the reasons why adolescent and pediatric trials are so important.” (Posted May 11, 2021)
“The safety data from the adolescent clinical trials looks similar to that for adults. With no major differences identified, and the robust vaccine safety monitoring systems we have in place for when vaccines are rolled out, I am confident in the safety profile of this vaccine for adolescents, and if an issue should arise, we are well-positioned to quickly identify and address this.” (Posted May 11, 2021)
“Yes, the side effects are very similar to those in adults. The most common side effects were pain at the injection site, fatigue, headache, chills, muscle aches, fever, and joint pain. Most of these were somewhat worse following the second dose. These side effects occur only for a limited time after vaccination, usually gone within 1-3 days.” (Posted May 11, 2021)
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Robert A. Bednarczyk, PhD, Assistant Professor of Global Health and Epidemiology, Emory University
C. Buddy Creech, MD, MPH, Director, Vanderbilt Vaccine Research Program, Associate Professor, Pediatric Infectious Diseases, Vanderbilt University School of Medicine and Medical Center
None that are relevant.
Richard Malley, MD, Senior Physician in Medicine, Division of Infectious Diseases, Boston Children’s Hospital; Professor of Pediatrics, Harvard Medical School
Dr. Malley is a scientific founder, board member and consultant at Affinivax, a biotechnology company in Cambridge, MA, that is dedicated to the development of novel vaccines. Dr. Malley has also received funding for research unrelated to COVID-19 vaccines by PATH, The Bill and Melinda Gates Foundation, Astellas and Pfizer. He is also a consultant for Merck on topics related to pneumococcal vaccines.
Paul Spearman, MD, Professor and Director of Infectious Diseases, Cincinnati Children’s Hospital
I hold NIH grants (NIH is involved in many current vaccine efforts). I am a member of the Leadership Group of the Infectious Diseases Clinical Research Consortium, which evaluates some COVID-related proposals. My division is conducting trials with the Pfizer and AstraZeneca COVID19 vaccines. I am a member of the Vaccines and Related Biological Products Advisory Committee (VRBPAC) of the FDA. My views are my own and do not represent those of the FDA.