A modelling study published in the Eurosurveillance journal states that Vaxzevria (AstraZeneca vaccine) may be more beneficial to groups that are 55 years or older. Researchers found that "...the number of COVID-19 deaths averted with the use of Vaxzevria in individuals 55 years and older was substantially higher than the expected number of deaths from TTS (clotting risk/adverse events of thrombosis in combination with thrombocytopenia) in that age group". The study found that it may not be as beneficial among the younger adults aged 18-39.