1. A two-dose regimen of BNT162b2 at 10μg elicits a sufficient immune response in children 5 – 11 years of age.
2. The two-dose regimen was shown to have a favorable safety profile in children 5 – 11 years of age.
Evidence Rating Level: 1 (Excellent)
Study Rundown: The BNT162b2 (Pfizer-BioNTech) vaccine was originally approved for use in individuals over the age of 16, but the eligibility has since expanded to include the 12-15 age group. The results of this trial have since expanded this eligibility to also include individuals between the age of 5-11. This study encompasses results of both the phase 1 dose-identification and phase 2-3 safety, immunogenicity, and efficacy ongoing trials. In phase 1, participants were given a two-dose regimen of BNT162b2 at different doses between 10 – 30 μg. Upon evaluating reactogenicity and immunogenicity, the 10 μg dose was selected which was used in the subsequent phase 2-3 trial. Selected children between the age of 5 – 11 were randomized in a 2:1 ratio to receive the two-dose BNT162b2 vaccine regimen or placebo. The evaluated neutralizing antibody titer against SARS-CoV-2 one month after administration was deemed to successfully meet the defined immunogenicity criterion and a high vaccine efficacy 7 days after the second dose. The rate of adverse events was similar between both groups with injection-site pain being the most common reaction. Overall, the study demonstrates that the BNT162b2 is safe and efficacious in children 5 – 11. The study is limited by short follow-up to assess the duration of immunity and lack of data in conjunction with other vaccines (vaccine mixing) in this age group.
In-Depth [randomized controlled trial]: This study presents data from both a phase 1, dose-determination study and an ongoing phase 2 -3 safety and efficacy evaluation of the BNT162b2 vaccine in children aged 5 – 11. In the phase 1 portion, 48 healthy children within the target age group were recruited to receive a two-dose regimen of BNT162b2 administered intramuscularly spaced 21 days apart at either 10, 20, or 30 μg. Immunogenicity was then determined by collecting blood samples and assessed for SARS-CoV-2 neutralizing antibodies compared to the levels of control-matched 16 – 25-year-old participants for reference. Children receiving the 30 μg dose had a greater incidence of side effects including fever, thus the group was discontinued. Given similar neutralizing antibody titers between 10 and 20 μg dosages, the 10 μg dose was selected. In phase 2-3 safety and efficacy trial, 2285 children were randomized in a 2:1 ratio to receive the two-dose regimen of BNT162b2 at 10 μg and followed for a median time of 2.3 months for Covid-19 infection incidence. Blood was collected 1 month after the second dose administration to assess neutralizing antibody titers. The study found that the geometric mean ratio in the vaccinated cohort successfully passed the immunobridging criterion defined by the FDA indicating sufficient immunogenicity. Moreover, the vaccine efficacy 7 days after the second dose was 90.7% (95% CI, 67.7 – 98.3). With respect to safety, the vaccinated group experienced a greater incidence of local and systemic events including fever, fatigue, and headache than the placebo group, especially after the second dose. However, beyond the second dose, adverse event incidence was similar between both groups (10.9%, vaccinated group vs. 0.2%, placebo). Taken altogether, this study supports the use of the BNT162b2 against SARS-CoV-2 in the 5 – 11 age group.
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