Effectiveness of BNT162b2 Vaccine against Omicron in Children 5 to 11 Years

25 Pages Posted: 28 Mar 2022

See all articles by Sharon Tan

Sharon Tan

National University of Singapore (NUS) - Saw Swee Hock School of Public Health

Alex R. Cook

National University of Singapore (NUS) - Saw Swee Hock School of Public Health; National University Health System (NUHS)

Derrick Heng

Ministry of Health, Singapore

Benjamin Ong

Ministry of Health, Singapore

David Chien Lye

National Centre for Infectious Diseases

Kelvin Bryan Tan

Ministry of Health, Singapore

Date Written: March 4, 2022

Abstract

Background
Since it was first identified in early November 2021, the coronavirus disease 2019 (Covid-19) B.1.1.529 (omicron) variant has spread quickly and replaced the B.1.617.2 (delta) variant as the dominant variant in many countries. Data on the real-world effectiveness of vaccines against the omicron variant for children is currently lacking.

Methods
We performed a study of 255,773 children between 5 to 11 years old in Singapore during the period from January 21 to February 24, 2022 when the omicron variant was rapidly spreading. Outcomes included the rates of all reported SARS-CoV-2 infections, polymerase chain reaction-confirmed infections, as well as hospitalizations among unvaccinated, partially vaccinated and fully vaccinated groups. The incidence rate ratio (IRR) of outcomes between different groups was obtained using a Poisson regression, including sex, race, age, housing type, and date of study as covariates.

Results
Among unvaccinated individuals, the incidences of all infections, PCR-confirmed infections and hospitalizations were 2744, 559, and 28 per million person-days. Compared with unvaccinated children, the adjusted IRRs for all infections, PCR-confirmed infections and hospitalizations for partially vaccinated children were 0.86 (95% CI, 0.84 to 0.89), 0.78 (95% CI, 0.72 to 0.83) and 0.66 (95% CI, 0.47 to 0.93) respectively. For fully vaccinated individuals, the IRRs were 0.57 (95% CI, 0.55 to 0.59), 0.36 (95% CI, 0.32 to 0.42), and 0.13 (95% CI, 0.04 to 0.36) respectively.

Conclusions
The BNT162b2 vaccine is associated with lower Covid-19 hospitalizations among children, and may aid in preventing pediatric healthcare systems from being overwhelmed during the omicron wave.

Note:
Funding Information: None to declare.

Conflict of Interests: None to declare.

Ethical Approval: Data collection and analysis for this study was carried out under the Infectious Disease Act to support policy decision-making and evaluation, and was exempted from ethics review.

Keywords: COVID-19, SARS-CoV-2, Vaccination, mRNA Vaccine, Child

Suggested Citation

Tan, Sharon and Cook, Alex R. and Heng, Derrick and Ong, Benjamin and Lye, David Chien and Tan, Kelvin Bryan, Effectiveness of BNT162b2 Vaccine against Omicron in Children 5 to 11 Years (March 4, 2022). Available at SSRN: https://ssrn.com/abstract=4052133 or http://dx.doi.org/10.2139/ssrn.4052133

Sharon Tan (Contact Author)

National University of Singapore (NUS) - Saw Swee Hock School of Public Health ( email )

12 Science Drive 2
#10-01
117549
Singapore

Alex R. Cook

National University of Singapore (NUS) - Saw Swee Hock School of Public Health ( email )

12 Science Drive 2
#10-01
117549
Singapore

National University Health System (NUHS) ( email )

1E, Kent Ridge Road
119228
Singapore

Derrick Heng

Ministry of Health, Singapore ( email )

College of Medicine
16 College Road
Singapore, 169854
Singapore

Benjamin Ong

Ministry of Health, Singapore ( email )

College of Medicine
16 College Road
Singapore, 169854
Singapore

David Chien Lye

National Centre for Infectious Diseases

Singapore

Kelvin Bryan Tan

Ministry of Health, Singapore ( email )

College of Medicine
16 College Road
Singapore, 169854
Singapore

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