HIPRA will initiate a clinical trial of its Covid-19 vaccine to evaluate immunogenicity and safety when it is administered as a 4th dose in people who have previously received three doses of Pfizer or two doses of Pfizer plus HIPRA's booster vaccine. The data from this upcoming trial will complement the HIPRA vaccine results obtained to date.

The trial will be conducted in 10 Spanish hospitals and will involve 200 adults. Participants will be monitored for 30 weeks to assess the long-term safety and the immune response.

The HIPRA vaccine is currently under review by the European Medicines Agency (EMA) to then be authorised for marketing.