ABSTRACT
Qatar was also hit hard by the global pandemic of SARS-CoV-2, with the original virus, Alpha variant, Beta variant, Omicron BA.1 and BA.2 variants, Omicron BA.4 and BA.5 variants, and Delta variant, sequentially. The two-dose primary series of BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine against SARS-CoV-2 infection has been approved for use in 30 µg formulations among children and adolescents aged 12-17 years as of 16 May 2021. This study aimed at estimating the effectiveness of the 30 µg BNT162b2 Pfizer-BioNTech mRNA COVID-19 vaccine against the pre-Omicron variants of SARS-CoV-2 infection in children and adolescents aged 12-17 years residing in Qatar. A test-negative matched case-control study was conducted. The subjects included any child or adolescent aged 12-17 years who had been tested for SARS-CoV-2 using RT-PCR tests performed on nasopharyngeal or oropharyngeal swabs, as part of contact tracing, between June and November 2021, and was eligible to receive the BNT162b2 vaccine as per the national guidelines. Data regarding 14,161 children/adolescents meeting inclusion-exclusion criteria were retrieved from the national Surveillance and Vaccine Electronic System (SAVES). Of the total, 3.1% (444) were positive for SARS-CoV-2. More than half (55.96%) were vaccinated with two doses of Pfizer-BioNTech-mRNA COVID-19 vaccine. Amongst those immunized with two doses, 1.2% tested positive for SARS-CoV-2, while 5.6% amongst the unvaccinated tested positive. The vaccine effectiveness was calculated to be 79%. Pfizer-BioNTech mRNA COVID-19 vaccine provides protection from COVID-19 infection for children/adolescents; hence, it is crucial to ensure they receive the recommended vaccines.
