Table 1.
Characteristic of studies included for vaccine effectiveness
| Ref. | Study design | Location | Purpose | Age of study group | Vaccine type | Number of doses received | Variant of concern |
|---|---|---|---|---|---|---|---|
|
| |||||||
| Baum et al[33], 2022 | Cohort study | Finland | To estimate VE against severe COVID-19 among the elderly | Adult Population including ≥ 70 yr old | Pfizer-BioNTech | 2 doses | Omicron |
| Grewal et al[34], 2022 | Case control design | Canada | To estimate vaccine effectiveness of mRNA vaccines among aged ≥ 60 yr who were tested for SARS-CoV-2 | ≥ 60 yr old | Pfizer-BioNTech and Moderna | Booster | Omicron |
| Rosenberg et al[35], 2021 | Cohort study | USA (NY) | To describe vaccine efficacy in NY | Adult Population including ≥ 50 yr old | Pfizer-BioNTech and Moderna | 2 doses | Delta |
| Rosero-Bixby[36], 2021 | Cross-sectional study | Costa Rica | To estimate the dose-dependent effectiveness of coronavirus disease (COVID-19) vaccines to prevent severe illness in real-world conditions | Adult Population including ≥ 58 yr old | Pfizer-BioNTech | 2 doses | Delta |
| Rane et al[37], 2022 | Case control study | USA (NY) | To monitor changes in vaccine effectiveness against COVID-19 outcomes for various vaccine products in different population subgroups | Adult Population including ≥ 50 yr old | Pfizer-BioNTech | 2 doses | Delta |
| Chemaitelly et al[38], 2021 | Case control study | Qatar | To estimate vaccine effectiveness against any SARS-CoV-2 infection and against any severe, critical, or fatal case of COVID-19 | Adult Population including ≥ 50 yr old | Pfizer-BioNTech | 2 doses | Delta |
| Lytras et al[39], 2022 | Cohort study | Greece | To estimate COVID-19 effectiveness against disease and death | Adult Population including ≥ 60 yr old | Pfizer-BioNTech and Moderna | 2 doses and booster | Delta |
| Ranzani et al[40], 2022 | Case control study | Brazil | To evaluate vaccine effectiveness against symptomatic COVID-19 and severe COVID-19 (hospital admission or deaths) | Adult Population including ≥ 70 yr old | Pfizer-BioNTech | 2 doses and booster | Omicron |
COVID-19: Coronavirus disease 2019; SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2; USA (NY): United States of America (New York); VE: Vaccine effectiveness.