Skip to content

Pfizer, Moderna vaccines cut COVID hospitalizations by 94% in older adults, CDC finds

The vaccines also reduced the likelihood of COVID-19 hospitalization in partially vaccinated adults 65 and older.
COVID vaccination 04282021
(Getty Images)

New data shows that the Pfizer and Moderna COVID-19 vaccines are capable of reducing coronavirus-related hospitalizations in fully vaccinated adults 65 years and older by 94 percent compared to unvaccinated adults of the same age.

The Centers for Disease Control and Prevention study released Wednesday also found that adults 65 and older who are partially vaccinated — meaning two weeks have passed since their first dose — are 64 percent less likely to be hospitalized with COVID-19.

These are the first real-world findings outside of laboratory settings that confirm what initial clinical trials revealed about COVID-19 vaccines’ ability to prevent serious illness.

“These findings are encouraging and welcome news for the two-thirds of people aged 65 and up who are already fully vaccinated,” CDC Director Dr. Rochelle Walensky said in a statement. “As our vaccination efforts continue to expand, COVID-19 patients will not overwhelm health care systems – leaving hospital staff, beds, and services available for people who need them for other medical conditions.”

The researchers studied a total of 417 coronavirus and non-coronavirus hospitalizations across 24 hospitals in 14 states. Among the patients, 187 tested positive for COVID-19 and 230 tested negative. Half were older than 75.

As expected, the team found that neither the Pfizer nor Moderna vaccines offered protection against hospitalization for people who had only been vaccinated with one shot for less than two weeks. Experts say it takes two weeks for the body to build an immune response after vaccination.

Earlier research from the CDC provided “strong evidence” that the Pfizer and Moderna vaccines are capable of preventing infections — both those that cause symptoms and those that don’t — in real-world conditions, McClatchy News reported in March.

The study found that risk of coronavirus infection dropped by 90 percent two weeks after receiving a second, final dose and by 80 percent two weeks following a single dose among nearly 4,000 health care workers, first responders and other essential workers across six states.

Preliminary vaccine effectiveness data from the U.S. also aligns with data from Israel, which has vaccinated the most people per capita in the world. The U.S. has vaccinated the most people in total.

Some people may still contract the coronavirus after maximum protection from the vaccine has been reached, however. That’s because no vaccine is 100 percent effective against illness. Experts call these cases “breakthrough infections.”

As of April 20, when about 87 million Americans had been fully vaccinated, 7,157 breakthrough infections were reported to the CDC. The majority were among women (64 percent) and nearly half were among those older than 60 (46 percent). There were 498 hospitalizations and 88 deaths among those cases.

Data on breakthrough cases is updated every Friday.

The Johnson & Johnson coronavirus vaccine was not included in the study. After about two weeks, the CDC and U.S. Food and Drug Administration lifted a pause placed on the shot after experts agreed the benefits of vaccination outweighed the risks of developing blood clots.

In total, there have been 15 cases of the clots following vaccination with the one-dose shot among nearly 8 million administered vaccines as of April 21. All of the cases were women ages 18 to 48.

More than 96.7 million Americans have been fully vaccinated against COVID-19, about 29 percent of the population, as of April 27, according to a CDC tracker.