Table 1.
Main characteristics of studies included in quantitative synthesis and meta-analysis.
| Study, Year | Design | Location | Duration | Population | Intervention | Control | Outcomes | Sample Size |
|---|---|---|---|---|---|---|---|---|
| Gong, 2020 [17] | Retrospective cohort study | China | 2006–2018 | 9–18 years old females | 4vHPV | 2vHPV 9vHPV |
Diagnoses of POI and related symptoms | 418 |
| Hviid, 2021 [15] | Retrospective cohort study | Denmark | 2007–2016 | Girls aged between 12–15 | 4vHPV vaccination | Unvaccinated girls | Diagnoses of POI | 1,051,041 |
| Naleway, 2018 [4] | Retrospective cohort study | USA | 2006–2014 | NA | HPV vaccinated girls | Other vaccine (tetanus toxoid, Tdap, influenza) | Risk of POI | 199,078 |
| Phillips, 2020 [16] | Retrospective cohort study | Australia | 2007–2017 | 12–13 years old male and female children | 4vHPV vaccination | Unvaccinated children | Adverse events of special interest following 4vHPV vaccination | 3221 |
NA: not available.