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Vaccination

Vaccine Efficacy in Children 5-11 Years Old: Waning Protection Over Time

Strategic Insights

— 2 min read

As the COVID-19 pandemic continues to evolve, new data has emerged highlighting the vaccine's performance in children 5-11 years old. The Pfizer-BioNTech vaccine, the only one authorized for this age group in the United States, has shown waning protection against infections over time, although it still provides robust protection against severe outcomes such as hospitalization and death. Experts point to the need to consider increasing the size of the dose 5- to 11-year-olds receive, as current data suggests the lower vaccine dose may not induce strong protective immune responses.

Key Takeaways:

  • The Pfizer-BioNTech vaccine's effectiveness against hospitalization and death in 5- to 17-year-olds has been consistently high, even after the emergence of the omicron variant, with a range of 73 to 88% effectiveness after five months.
  • Children 5 to 11 years old were not eligible for vaccination until early November 2021, and by mid-December, most had completed their two-dose series; 23 vaccinated children were hospitalized with covid-like symptoms, compared to 262 unvaccinated children.
  • The CDC study found that vaccine efficacy decreased over time, with 92-94% effectiveness for 12- to 17-year-olds against hospitalization during the delta and omicron waves, compared to 51% in 5- to 11-year-olds.
  • For fully vaccinated 12- to 17-year-olds, protection ranged between 34% for older teens and 45% for younger adolescents against emergency department and urgent care visits during the omicron surge, with protection rising to 81% for older teens who received boosters.
  • The New York state data released showed a rapid and steep drop in vaccine effectiveness against infection in 5- to 11-year-olds compared to adolescents, with protection falling from 68% to 12% during the omicron surge.
  • Protection against hospitalization in 5- to 11-year-olds fell from 100% to 48% during the same period.
  • New York State health commissioner Mary Bassett emphasized that vaccination remains recommended for everyone 5 and older, despite reduced vaccine effectiveness.

Statistics:

  • The Pfizer-BioNTech vaccine was 92 to 94% effective against hospitalization in 12- to 17-year-olds during the delta and omicron waves.
  • Two doses of the vaccine were about 51% effective in preventing 5- to 11-year-olds from going to emergency departments and urgent care centers as omicron spread.
  • Unvaccinated 5- to 11-year-olds were 1.3 times more likely to get infected during January compared to those who were vaccinated.
  • Unvaccinated 12- to 17-year-olds were 1.5 times more likely to get infected during the same period.
  • Nine covid deaths occurred in vaccinated children 5-17 years old between April 4, 2021, and Jan. 1, compared to 121 deaths among unvaccinated children.
  • Protection against infection for 5- to 11-year-olds fell from 68% to 12% during the omicron surge in New York state data.

Sources:

  • Centers for Disease Control and Prevention (CDC)
  • New York State Health Department
  • Weill Cornell Medicine
  • Yale University School of Public Health
  • Emory University
  • Pfizer-BioNTech vaccine trial
  • New York State health commissioner Mary Bassett's statement.

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