COVID Vaccine Effectiveness Tested in Unconventional Trials

Main finding: Researchers found that vaccines are still effective against new variants of COVID-19, despite concerns about their ability to protect against emerging strains. The study combined data from both randomized controlled trials and non-randomized studies to get a clearer picture of how well the vaccines worked during this time. This approach allowed them to provide more accurate information on vaccine effectiveness, which is crucial for making informed decisions about public health measures.