Vaccination strategy comparison (IMAGE) American Institute of Physics Caption The number of people vaccinated once (yellow) and twice (green) under the prime first and prime boost scenarios. Prime first vaccinates double the number of people initially, while prime boost focuses on full vaccinations. Credit Lucas Böttcher and Jan Nagler Usage Restrictions Journalists may use this image only with appropriate credit. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.