The Lancet Infectious Diseases journal Friday, and highlighted the protection shots provide against hospitalization from both variants.
The study assessed positive cases that occurred between March 29 and May 23, analyzing samples of the virus using whole-genome sequencing to determine which variant a person was infected with.
Nearly three-quarters of the patients were unvaccinated, 24% were partially vaccinated and 2% had received both shots. Early studies of the delta variant, which first appeared in India in December, found it was 50% more transmissible than other strains.
It quickly spread around the world to more than 130 countries, becoming the dominant variant in many. As children return to school this fall and countries abandon