Adverse events of special interest following the use of BNT162b2 in adolescents: a population-based retrospective cohort study

Abstract

Accruing evidence suggests an increased risk of myocarditis in adolescents from messenger RNA COVID-19 vaccines. However, other potential adverse events remain under-researched. We conducted a retrospective cohort study of adolescents aged 12–18 with a territory-wide electronic healthcare database of the Hong Kong population linked with population-based vaccination records and supplemented with age- and sex-specific population numbers. Two age- and sex-matched retrospective cohorts were formed to observe 28 days following the first and second doses of BNT162b2 and estimate the age- and sex-adjusted incidence rate ratios between the vaccinated and unvaccinated. Thirty AESIs adapted from the World Health Organization’s Global Advisory Committee on Vaccine Safety were examined. Eventually, the first-dose cohort comprised 274,881 adolescents (50.25% received the first dose) and the second-dose cohort 237,964 (50.29% received the second dose). Ninety-four (34.2 per 100,000 persons) adolescents in the first-dose cohort and 130 (54.6 per 100,000 persons) in the second-dose cohort experienced ≥1 AESIs. There were no statistically significant differences in the risk of any AESI associated with BNT162b2 except myocarditis [first-dose cohort: incidence rate ratio (IRR) = 9.15, 95% confidence interval (CI) 1.14–73.16; second-dose cohort: IRR = 29.61, 95% CI 4.04–217.07] and sleeping disturbances/disorders after the second dose (IRR = 2.06, 95% CI 1.01–4.24). Sensitivity analysis showed that, with myocarditis excluded as AESIs, no significantly elevated risk of AESIs as a composite outcome associated with vaccination was observed ( P = 0.195). To conclude, the overall absolute risk of AESIs was low with no evidence of an increased risk of AESIs except myocarditis and sleeping disturbances/disorders.

SARS-CoV-2 B.1.1.529 (Omicron) Variant Causes an Unprecedented Surge in Children Hospitalizations and Distinct Clinical Presentation Compared to the SARS-CoV-2 B.1.617.2 (Delta) Variant

“…Unfortunately, children under 5 years of age cannot benefit from the vaccination as available SARS-CoV-2 vaccines are recommended for older children. Although the BNT162b2 COVID-19 vaccine has been deemed safe, immunogenic, and effective in preventing COVID-19 infection (16), concerns have arisen regarding the risk of myocarditis, especially in adolescents (32)(33)(34)(35). This could explain why vaccination rates remain low in children aged 5-11 years old (36).…”

Risk of acute liver injury following the mRNA (BNT162b2) and inactivated (CoronaVac) COVID-19 vaccines

“…Records were linked using a unique de-identified mapping key. These 2 linked sources of data have been extensively used for COVID-19 vaccine pharmacovigilance research [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] and drug-induced liver injury research. 26 …”

Adverse events of special interest and mortality following vaccination with mRNA (BNT162b2) and inactivated (CoronaVac) SARS-CoV-2 vaccines in Hong Kong: A retrospective study

“…The validity of disease diagnoses identified from electronic medical records has been shown to be high [ 33 – 38 ]. These 2 linked sources of data have been extensively used for pharmacovigilance and COVID-19 vaccine safety studies [ 18 , 28 , 39 – 45 ].…”

“…Previous research validating ICD-9-CM diagnostic codes in Hospital Authority data estimated the positive predictive value at >85% [ 33 ]. The Hospital Authority database has previously been used extensively for COVID-19 vaccination safety and pharmacovigilance studies, one of which quantified risks of AESIs following COVID-19 vaccination [ 39 , 40 ]. Outcome events were recorded during the 21 days of post-vaccination follow-up, except for anaphylaxis, for which the observation period was restricted to 2 days after each vaccine dose.…”