SARS-CoV-2 Infections and Hospitalizations among Persons 16 Years and Older by Vaccination Status - Los Angeles County, California, May 1 to July 25, 2021

Jennifer B. Griffin, PhD 1 ; Meredith Haddix, MPH 1 ; Phoebe Danza, MPH 1 ; Rebecca Fisher, MPH 1 ; Tae Hee Koo, MPH 1 ; Elizabeth Traub, MPH 1 ; Prabhu Gounder, MD 1 ; Claire Jalashow, PhD No. 2 ; Sharon Balter, MD

Commentary

This study looked at COVID-19 vaccination and morbidity and hospitalization rates.

Although the COVID-19 vaccine is now generally considered to be very effective, it is still the case that some people who are fully vaccinated in some cases become infected with SARS-CoV-2.

From May 1, 2021 to July 25, 2021, of the 43,127 SARS-CoV-2 infections among residents of Los Angeles County, California, 10,895 (25.3%) were fully vaccinated and 1,431 (3.3%) were partially vaccinated. 

The remaining (71.4%) were unvaccinated. The infection and hospitalization rates among the unvaccinated were found to be 29.2 times higher than those among the fully vaccinated.

In July, when the delta variant prevailed, the cycle threshold values for unvaccinated, partially vaccinated and vaccinated people were similar.

All of this provided evidence that efforts to increase COVID-19 vaccination coverage, in conjunction with other strategies for infection control, remain necessary.