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Real-World Immunogenicity and Reactogenicity of Two Doses of Pfizer-BioNTech COVID-19 Vaccination in Children Aged
Gili Joseph1, Elisheva Klein1, Yaniv Lustig2,3
1The Sheba Pandemic Preparedness Research Institute (SPRI), and Infection Prevention & Control Unit, Sheba Medical Center, Tel Hashomer, Ramat Gan 52621, Israel.
Insights
Pfizer-BioNTech COVID-19 vaccination in children aged 5-11 years showed strong immunogenicity and a safe reactogenicity profile. Antibody titers remained elevated for 180 days, suggesting potentially longer durability than in adults.
Area of Science:
- Pediatric Vaccinology
- Immunology
- Infectious Diseases
Background:
- Limited data exist on COVID-19 vaccine immunogenicity and reactogenicity in children.
- Understanding vaccine response in pediatric populations is crucial for public health strategies.
Purpose of the Study:
- To evaluate the immunogenicity, reactogenicity, and durability of the Pfizer-BioNTech COVID-19 vaccine in children aged 5-11 years.
- To assess the occurrence of breakthrough infections and their impact on immune response.
Main Methods:
- A cohort of 110 children (5-11 years) received two doses of the Pfizer-BioNTech COVID-19 vaccine.
- Immunogenicity (IgG titers, neutralizing antibodies), reactogenicity (adverse events), and breakthrough infections were monitored over 180 days.
Main Results:
- Antibody titers demonstrated robust immunogenicity, with sustained levels up to 180 days post-vaccination.
- The vaccine was found to be safe, with mild, transient adverse events; no serious adverse events were reported.
- A high rate of mild breakthrough infections (75.5%) was observed, with some evidence of enhanced antibody response in infected children.
Conclusions:
- Two doses of the Pfizer-BioNTech COVID-19 vaccine are safe and immunogenic in children aged 5-11 years.
- The observed durability of immune response suggests a potentially longer interval before booster vaccination is needed compared to adults.
- Further research may inform optimal pediatric COVID-19 vaccination schedules.
Abstract:
There are limited data concerning the immunogenicity and reactogenicity of COVID-19 vaccines in children. A total of 110 children, 5-11 years old were vaccinated with two doses (with a 3-week interval between doses) of the Pfizer-BioNTech COVID-19 vaccine and were followed for 21, 90, and 180 days after vaccination for immunogenicity, adverse events, and breakthrough infections. Ninety days after the first vaccine dose, the GeoMean (CI 95%) of IgG ascended to 1291.0 BAU (929.6-1790.2) for uninfected children and 1670.0 BAU (1131.0-2466.0) for Infected children. One hundred and eighty days after receiving the first dose of the vaccine, the titers decreased to 535.5 BAU (288.4-993.6) for the uninfected children, while only a small decline was detected among infected children-1479.0 (878.2-2490.0). The neutralizing antibodies titer almost did not change over time in the uninfected children, and even elevated for the infected children. Of the 110 vaccinated children, 75.5% were infected, with only mild COVID-19 infection symptoms. Child vaccination was found to be safe, with mild, mostly local, and of short duration, reported AEs. No serious adverse events (SAEs) were reported after vaccination. The durability of two doses of vaccine in children is longer, thus a booster may not be needed as early as in adults.
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