COVID-19 Booster Shots Are 90 Percent Effective Against Hospitalization

Unvaccinated Americans over age 50 are 44 times more likely to be hospitalized than triple-vaccinated folks.


The booster shots of the Moderna and Pfizer/BioNTech COVID-19 vaccines are around 90 percent effective against hospitalization for folks infected with the omicron variant, according to an analysis released by the Centers for Disease Control and Prevention (CDC). Researchers at the agency used diagnosis and admission data between August 26, 2021, and January 5, 2022, from nearly 400 emergency care units and 260 hospitals in 10 states to make those calculations.

"These findings underscore the importance of receiving a third dose of mRNA COVID-19 vaccine to prevent both moderately severe and severe COVID-19, especially while the Omicron variant is the predominant circulating variant and when the effectiveness of 2 doses of mRNA vaccines is significantly reduced against this variant," notes the agency.

This new CDC study is in line with another released yesterday reporting that unvaccinated Americans between the ages of 50–64 and those 65 and older were, respectively, 44 times and 49 times more likely to be hospitalized in December with COVID-19 infections than vaccinated people in those age groups who have received booster shots. The CDC's hospitalization risk rates are based on COVID-19 infections tracked by the agency through December 25, 2021. That means that those calculations are largely based on delta variant infections and do not include much data from the omicron variant surge, which is now hopefully peaking.


Overall, the agency calculated that unvaccinated adults over age 18 were 16 times more likely to be hospitalized than were fully vaccinated people.


The above chart shows the age-adjusted COVID-19 hospitalization rate per 100,000 Americans the week before Christmas 2021. The number of Americans in hospitals diagnosed with COVID-19 infections stood at just over 71,000 on December 25 and is now nearly 160,000. The daily average COVID-19 death toll rose from just over 1,300 to around 2,000 now.

Let's also take a quick look at more recent data from the Canadian province of Alberta to get some sense of how the omicron variant is affecting COVID-19 disease trends among older unvaccinated and vaccinated people.

Alberta public health authorities report that as of January 19, the COVID-19 hospitalization rate for folks aged 60–69 who are tripled-vaccinated (boosted) is 21 per 100,000 people, double-vaccinated is 186 per 100,000, and unvaccinated is 1,225 per 100,000. In other words, unvaccinated Canadians in that age group are 58 times more likely to be hospitalized than individuals who have gotten their booster shots. Overall, the risk of hospitalization per 100,000 for those over age 5 stands at 41 for triple-vaccinated, 87 for double-vaccinated, and 600 for unvaccinated Albertans.

The intensive care unit (ICU) hospitalization rate per 100,000 for those folks between the ages of 60 and 69 years is 1.6 for the triple-vaccinated, 31.5 for the double-vaccinated, and 896 for the unvaccinated. The age 5 and up ICU hospitalization rate per 100,000 is 2.2 for triple-vaccinated Albertans, 8.7 for the double-vaccinated, and 131.4 for the unvaccinated.

One hopes that these data will encourage Americans who are still unvaccinated or unboosted to go get their shots.

Disclosure: I got two doses of Moderna back in February and March and a Pfizer booster in October last year.