Criteria for considering studies for this systematic review

Types of studies

We include parallel or cluster-randomized controlled trials (RCTs) evaluating the efficacy, immunogenicity and safety of COVID-19 vaccines in humans. Single-arm studies, non-randomized studies and modelling studies of interventions for COVID-19 are not included in the review. We have no restriction on language.

Types of participants

Children or adults with no restriction on age and comorbidities

Types of interventions

Eligible interventions include any COVID-19 vaccines particularly:

  • Live attenuated virus vaccine
  • Inactivated virus vaccine
  • Protein subunit vaccine
  • Virus-Like particle (VLP) vaccine
  • Non-replicating viral vector (e.g., recombinant adenovirus) vaccine
  • Replicating viral vector vaccine
  • DNA based vaccine
  • RNA based vaccine

    Type of comparator

    Placebo (placebo could consist of saline placebo, injecting only the vaccine adjuvant or injecting vaccine protecting for other diseases such as meningococcal conjugate vaccine), no vaccine or another COVID-19 vaccine.

    List of outcomes:

    Critical outcomes:

    Important outcomes: