The European Medicines Agency (EMA) has released guidance for developers of vaccines against COVID-19 on the clinical evidence that must be included in applications for marketing authorisation.
With regard to clinical efficacy, the document states that at least one well-designed large-scale phase 3 efficacy trial would be required to support the marketing authorisation of a COVID-19 vaccine. The primary analysis of efficacy should be restricted to study participants who were seronegative for the virus at baseline as it is important to show that the vaccine protects subjects not likely to have been exposed to the virus before. However, the secondary analysis should include an estimate of protection against symptomatic disease in study participants regardless of whether they were seronegative or seropositive for SARS-CoV-2 at study baseline.
With regard to clinical safety, the document also confirms that the evaluation of SARS-CoV-2 vaccines will follow the standard principles outlined in EMA guidance documents.
Furthermore, the EMA has recommended that clinical trial participants are followed for safety and efficacy with their randomised groups for at least one year after completing vaccination.
For further information consult the “EMA considerations on COVID-19 vaccine approval” document on the EMA website.