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BNT162b2 Protection against the Omicron Variant in Children and Adolescents
Ashley M Price1, Samantha M Olson1, Margaret M Newhams1
1From the Covid-19 Response Team, Centers for Disease Control and Prevention (A.M.P., S.M.O., M.W.T., L.D.Z., A.P.C., M.M.P.), the Center for Childhood Infections and Vaccines of Children's Healthcare of Atlanta and the Department of Pediatrics, Emory University School of Medicine (S.K.), and the Division of Critical Care Medicine, Department of Pediatrics, Emory University School of Medicine, Children's Healthcare of Atlanta (K.M.T.) - all in Atlanta; the Department of Anesthesiology, Critical Care, and Pain Medicine, Boston Children's Hospital (M.M.N., A.G.R.), and the Departments of Anaesthesia and Pediatrics, Harvard Medical School (A.G.R.) - both in Boston; the Division of Pediatric Infectious Diseases, Department of Pediatrics, Vanderbilt University Medical Center, Nashville (N.B.H.); the Department of Pediatrics, Baylor College of Medicine, Immunization Project, Texas Children's Hospital, Houston (J.A.B., L.C.S.), and the Department of Pediatrics, Division of Critical Care Medicine, University of Texas Southwestern, Children's Medical Center, Dallas (M.M.); the Division of Infectious Diseases, Children's Hospital Los Angeles and Departments of Pediatrics and Molecular Microbiology and Immunology, University of Southern California, Los Angeles (P.S.P.), the Division of Pediatric Hospital Medicine, UC San Diego-Rady Children's Hospital, San Diego (M.A.C.), the Division of Critical Care Medicine, UCSF Benioff Children's Hospital, Oakland (N.Z.C.), and the Department of Pediatrics, Divisions of Critical Care Medicine and Allergy, Immunology, and Bone Marrow Transplant, University of California, San Francisco, San Francisco (M.S.Z.) - all in California; Section of Pediatric Critical Care, Department of Pediatrics, Arkansas Children's Hospital, Little Rock (K.I.); the Division of Pediatric Critical Care Medicine, Nationwide Children's Hospital Columbus (K.E.B.), the Division of Critical Care Medicine, Department of Pediatrics, Akron Children's Hospital, Akron (R.A.N.), and the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati (M.A.S.) - all in Ohio; the Department of Pediatrics, Section of Critical Care Medicine, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora (A.B.M.); the Department of Pediatrics, University of North Carolina at Chapel Hill Children's Hospital, Chapel Hill (T.C.W., S.P.S.); the Division of Pediatric Critical Care Medicine (E.H.M.) and the Department of Pediatrics (L.S.), Medical University of South Carolina, Charleston; the Division of Pediatric Infectious Diseases, Department of Pediatrics, Children's Mercy Kansas City, Kansas City, MO (J.E.S.); the Departments of Pediatrics and Microbiology, Division of Infectious Diseases, University of Mississippi Medical Center, Jackson (C.V.H.); the Department of Pediatrics, Division of Cardiology, Louisiana State University Health Sciences Center and Children's Hospital of New Orleans, New Orleans (T.T.B.); the Divisions of Pediatric Infectious Diseases and Pediatric Critical Care Medicine, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester (E.R.L.), and the Division of Pediatric Critical Care, University of Minnesota Masonic Children's Hospital, Minneapolis (J.R.H.) - both in Minnesota; the Division of Critical Care Medicine, Department of Anesthesiology and Critical Care, Children's Hospital of Philadelphia, Philadelphia (K.C.); the Ryan White Center for Pediatric Infectious Disease and Global Health, Department of Pediatrics, Indiana University School of Medicine, Indianapolis (S.S.B.); the Division of Pediatric Critical Care Medicine, Children's Hospital of Michigan, Central Michigan University, Detroit (S.M.H.), and the Division of Pediatric Critical Care Medicine, Department of Pediatrics, Mott Children's Hospital and University of Michigan, Ann Arbor (H.R.F.); the Division of Pediatric Critical Care, Department of Pediatrics, Children's Hospital and Medical Center, Omaha, NE (M.L.C.); the Division of Pediatric Critical Care, Department of Pediatrics, Cooperman Barnabas Medical Center, Livingston, NJ (S.J.G.); the Division of Critical Care Medicine, Department of Pediatrics, Northwestern University Feinberg School of Medicine, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago (B.M. Coates); the Division of Pediatric Critical Care Medicine, Department of Pediatrics, University of Alabama at Birmingham, Birmingham (M.K.); the Division of Pediatric Infectious Diseases, Department of Pediatrics, UHealth Holtz Children's Hospital, Miami (B.M. Chatani); and the Department of Pediatrics and Banner Children's at Diamond Children's Medical Center, University of Arizona, Tucson (K.V.T.).
Insights
Two doses of the BNT162b2 vaccine offered significant protection against critical Covid-19 in children and adolescents. Vaccine effectiveness against hospitalization was lower for the Omicron variant compared to Delta, especially in adolescents.
Area of Science:
- Pediatric Infectious Diseases
- Vaccinology
- Public Health
Background:
- The emergence of the SARS-CoV-2 Omicron variant raised concerns regarding vaccine effectiveness and duration of protection in pediatric populations.
- Increased hospitalizations in children and adolescents due to COVID-19 underscored the need to evaluate current vaccine performance.
Purpose of the Study:
- To assess the effectiveness of the BNT162b2 mRNA vaccine against COVID-19 hospitalization and critical illness in children and adolescents.
- To compare vaccine effectiveness during the circulation of the Delta and Omicron variants.
Main Methods:
- A test-negative, case-control study design was employed.
- Data were collected from 31 hospitals across 23 states between July 2021 and February 2022.
- Vaccine effectiveness was estimated by comparing vaccination status between COVID-19 cases and controls, stratified by age group and variant circulation period.
Main Results:
- During the Delta variant period, vaccine effectiveness against COVID-19 hospitalization in adolescents (12-18 years) was high (93% at 2-22 weeks, 92% at 23-44 weeks).
- During the Omicron variant period, vaccine effectiveness against hospitalization was 40% in adolescents (12-18 years) and 68% in children (5-11 years).
- Vaccination demonstrated significant effectiveness against critical COVID-19 (79%) in adolescents during the Omicron period and prevented critical illness from both Delta and Omicron variants.
Conclusions:
- BNT162b2 vaccination significantly reduced Omicron-associated hospitalizations in children aged 5-11 by two-thirds.
- While protection against Omicron hospitalization was reduced in adolescents compared to Delta, vaccination remained crucial in preventing severe disease from both variants.
Background:
Spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.529 (omicron) variant, which led to increased U.S. hospitalizations for coronavirus disease 2019 (Covid-19), generated concern about immune evasion and the duration of protection from vaccines in children and adolescents.
Methods:
Using a case-control, test-negative design, we assessed vaccine effectiveness against laboratory-confirmed Covid-19 leading to hospitalization and against critical Covid-19 (i.e., leading to receipt of life support or to death). From July 1, 2021, to February 17, 2022, we enrolled case patients with Covid-19 and controls without Covid-19 at 31 hospitals in 23 states. We estimated vaccine effectiveness by comparing the odds of antecedent full vaccination (two doses of BNT162b2 messenger RNA vaccine) at least 14 days before illness among case patients and controls, according to time since vaccination for patients 12 to 18 years of age and in periods coinciding with circulation of B.1.617.2 (delta) (July 1, 2021, to December 18, 2021) and omicron (December 19, 2021, to February 17, 2022) among patients 5 to 11 and 12 to 18 years of age.
Results:
We enrolled 1185 case patients (1043 [88%] of whom were unvaccinated, 291 [25%] of whom received life support, and 14 of whom died) and 1627 controls. During the delta-predominant period, vaccine effectiveness against hospitalization for Covid-19 among adolescents 12 to 18 years of age was 93% (95% confidence interval [CI], 89 to 95) 2 to 22 weeks after vaccination and was 92% (95% CI, 80 to 97) at 23 to 44 weeks. Among adolescents 12 to 18 years of age (median interval since vaccination, 162 days) during the omicron-predominant period, vaccine effectiveness was 40% (95% CI, 9 to 60) against hospitalization for Covid-19, 79% (95% CI, 51 to 91) against critical Covid-19, and 20% (95% CI, -25 to 49) against noncritical Covid-19. During the omicron period, vaccine effectiveness against hospitalization among children 5 to 11 years of age was 68% (95% CI, 42 to 82; median interval since vaccination, 34 days).
Conclusions:
BNT162b2 vaccination reduced the risk of omicron-associated hospitalization by two thirds among children 5 to 11 years of age. Although two doses provided lower protection against omicron-associated hospitalization than against delta-associated hospitalization among adolescents 12 to 18 years of age, vaccination prevented critical illness caused by either variant. (Funded by the Centers for Disease Control and Prevention.).
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