The CDC has published numerous studies regarding Pfizer's COVID-19 vaccine efficacy among children and adolescents.
Currently, Pfizer's vaccine is the only one available to children ages 5-17. Becker's has summarized two recent report findings on vaccine effectiveness among children and adolescents. Data indicates rapidly waning vaccine effectiveness against infection amid omicron but not necessarily against hospitalization or deaths, though limitations to studies leave many questions unanswered.
Seven recent findings:
1. Two vaccine doses protect against COVID-19 emergency department and urgent care encounters among children and adolescents, according to CDC data published March 1. The data comes from a multistate analysis of 39,217 encounters from April 2021-January 2022.
2. However, the same study found vaccine effectiveness against infection was lower during omicron predominance and decreased with time since vaccination. According to the report, "During omicron predominance, there was no evidence of protection for adolescents aged 12-17 years from two doses received more than 150 days earlier."
3. A third vaccine dose restored vaccine effectiveness to 81 percent among adolescents ages 16-17.
4. Additional data is needed to better understand duration of protection against COVID-19 hospitalization in adolescents ages 12-17, the protection from three doses and the level of protection among children ages 5-11, according to the CDC.
5. Overall, two-dose vaccine effectiveness against COVID-19 hospitalization ranged from 73 to 94 percent.
6. The findings must be interpreted with caution, as the study included unvaccinated adolescents who had some immunity from prior infection.
7. The findings follow CDC findings published Feb. 28 that suggest Pfizer's vaccine offers significantly less protection against infection in children ages 5-11 compared with older kids and adults. The data was taken amid the height of New York state's omicron surge.
What experts are saying
"We need to see more of these studies to see if this is consistent," Deepta Bhattacharya, PhD, an immunologist at Tucson-based University of Arizona, told The New York Times. "But I do think it's likely, and we should be prepared as parents, that it's going to take another shot."
"Are we comparing apples to apples when we say that the vaccine efficacy is going down?" asked Paul Offit, MD, pediatrician, director of the Vaccine Education Center at Children's Hospital of Philadelphia and an adviser to the FDA. He noted that as more of the population gains immunity through infection, it gets harder to have a true picture of vaccine effectiveness.