BNT162b2 Protection against the Omicron Variant in Children and Adolescents

Abstract

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.)

Effectiveness of BBIBP-CorV, BNT162b2 and mRNA-1273 vaccines against hospitalisations among children and adolescents during the Omicron outbreak in Argentina

“…These results are consistent with recent studies conducted in similar age groups. [24][25][26][27] VE against hospitalisation, ICU admission and death in vaccine clinical trials and in subsequent real-world studies, including previous variants of SARS-COV-2 in the paediatric population, was higher than 90%. [14][15][16][17]22,23 However, since the identification of Omicron VOC, new data has become available reporting a significant reduction of the immune sera neutralising capacity of vaccinated or infected subjects with this variant compared to previous ones.…”

“…25 In a recent case-control test-negative study carried out in the US, VE against hospitalisation was 68% for the 5-11-year subgroup. 26 A recent Chilean study performed in 3-5-year-old children who received a two-dose scheme of an inactivated vaccine (CoronaVac) during the Omicron outbreak reported a VE against hospitalisation and ICU admission of 64% and 69%, respectively. Our findings are consistent with published studies.…”

“…Recently, four studies about vaccine effectiveness of BNT162b2 (Pfizer-BioNTech) and Coronavac (Sinovac) carried out in 3-11-year-old children during the Omicron period demonstrated that COVID-19 vaccines elicited less protection in the younger group and exhibited faster waning. [24][25][26][27] The aim of this study is to evaluate the effectiveness of COVID-19 vaccines authorised in Argentina against hospitalisations in 3-17-year-old children and adolescents in Buenos Aires Province during the Omicron outbreak. Our hypothesis is that the two-dose-scheme of vaccination in this age group is associated with lower incidence of hospitalisations.…”

Pädiatrie aktuell – Forschung kurz notiert

“…Eine im New England Journal of Medicine publizierte Fallkontrollstudie [ 2 ] untersuchte die Wirksamkeit des mRNA-Impfstoffes BNT162b2 (Pfizer) gegen die Virusvarianten Delta (B.1.617.2) und Omicron (B.1.1.529). Als geimpft wurden jene Kinder und Jugendlichen eingestuft, die 2 Dosen des mRNA-Impfstoffes erhalten hatten.…”

Maske rauf, Maske runter

“…Bei Jugendlichen zwischen 12 und 18 Jahren war die Effektivität nach zwei Impfungen gegen Spitalsaufnahme 40 %, gegen kritische COVID-19-Erkrankung 79 %, aber nur 20 % gegen mildes COVID-19 [ 3 ]. Diese Erkenntnisse scheinen zu unterstützen, dass Vakzine gegen SARS-CoV‑2 vermutlich in der Zukunft an veränderte Virusstämme angepasst werden müssen, da die Effektivität sonst nicht gewährleistet werden kann.…”