Vaccine Effectiveness of BNT162b2 Against Omicron in Children Aged 5-11 Years: A Test-Negative Design

BNT162b2 Effectiveness Against Delta and Omicron Variants of Severe Acute Respiratory Syndrome Coronavirus 2 in Adolescents Aged 12–17 Years, by Dosing Interval and Duration

“…Our findings reinforce the general understanding that VE is not compromised by a longer interval between the first and second doses; conversely, our findings bolster observations elsewhere and among other pediatric and adult age groups that VE may be improved when the dosing interval is extended [ 4 , 25 ]. Vaccine passports or cards were required to attend social or recreational settings, applicable to adolescents in both provinces starting September 2021 and lifted in mid-March (Quebec) or early April (Bc) 2022.…”

Safety and effectiveness of vaccines against COVID-19 in children aged 5–11 years: a systematic review and meta-analysis

“… NRSI 3 27 595 per 100 000 12 418 per 100 000 (11 038 to 13 798) VE 55% (50–60); VE ratio 0·45 (0·40–0·50) Up to ≥3 months after third dose 60 574 32 Moderate; downgraded by one level for serious imprecision (one study only) Booster vaccination probably reduces the risk of SARS-CoV-2 infections with omicron. Symptomatic COVID-19 NRSI 2 31 326 per 100 000 19 203 per 100 000 (15 005 to 24 528) VE 36·2% (21·5–48·2); VE ratio 0·638 (0·518–0·749) ≥7 days after second dose to median of 4 months after second dose 3 262 727 32 , 45 , 48 , 49 , 50 , 51 Low; downgraded by two levels for serious inconsistency ( I 2 =92·2%) Primary vaccination series probably slightly reduces the risk of symptomatic COVID-19. NRSI 3 NR § NE VE 61% (55–67); VE ratio 0·39 (0·33–0·45) Up to ≥3 months after third dose 60 574 32 Moderate; downgraded by one level for serious imprecision (one study only) Booster vaccination probably reduces the risk of symptomatic COVID-19.…”

“… NRSI 3 NR § NE VE 61% (55–67); VE ratio 0·39 (0·33–0·45) Up to ≥3 months after third dose 60 574 32 Moderate; downgraded by one level for serious imprecision (one study only) Booster vaccination probably reduces the risk of symptomatic COVID-19. Hospitalisation due to COVID-19 NRSI 2 47 per 100 000 ¶ 12 per 100 000 (9 to 15) VE 75·3% (68·0–81·0); VE ratio 0·25 (0·19–0·32) ≥7 days after second dose to median of 71 days after second dose 3 058 480 43 , 49 , 50 , 51 , 52 , 53 Moderate; downgraded by one level for risk of bias (two studies with a serious risk and four studies with a moderate risk) Primary vaccination series probably reduces the risk of hospitalisation due to omicron variant-induced COVID-19. NRSI 3 NA NA VE NA NA 0 NA Outcome was not reported in any study.…”

“…Three studies assessed vaccine effectiveness over time and also found a reduction of vaccine effectiveness against symptomatic COVID-19 from the timepoint of first measurement of the second dose to the timepoint of last measurement of at least 8% ( appendix 1 p 40 ). 49 , 51 Vaccine effectiveness against symptomatic COVID-19 could be restored to higher levels after the third dose (61% [55–67]). 32 …”

“…Although vaccine efficacy from RCTs 24 , 25 was based on incidence rate ratios, considering person-years to address surveillance time, vaccine effectiveness from NRSIs was calculated on the basis of incidence rate ratios, 29 , 30 , 40 , 42 , 49 , 50 hazard ratios, 43 , 44 , 47 RRs, 45 or ORs. 27 , 28 , 32 , 46 , 48 , 51 , 52 , 53 , 54 However, no outliers were identified in meta-analyses. Therefore, the calculation of vaccine effectiveness estimates are unlikely to have had a substantial effect on the overall effect.…”