WASHINGTON D.C.: COVID-19 vaccines are highly effective in preventing hospitalizations and deaths, even against the highly contagious Delta variant, according to new U.S. studies.

Based on a study that monitored over 600,000 COVID-19 cases in 13 states from April to mid-July while the Delta variant surged, the Centers for Disease Control and Prevention has confirmed unvaccinated people were 4.5 times more likely than those fully vaccinated to be infected, over 10 times more likely to be hospitalized, and 11 times more likely to die.

At a White House briefing late last week, CDC Director Dr. Rochelle Walensky said, “Vaccination works. We have the scientific tools we need to turn the corner on this pandemic.”

Over 90 percent of Americans hospitalized with COVID-19 are unvaccinated, she added.

However, the study also found vaccine-induced resistance dropped from 91 percent in the spring to 78 percent in June and July, with “breakthrough” cases, or those catching the virus despite being fully vaccinated, accounting for 14 percent of hospitalizations and 16 percent of deaths in June and July.

The CDC released two other studies last Friday that suggested older adults were less protected, even after vaccination. One found the protection rate for those 75 and older was 76 percent compared with 89 percent for all other adults, after examining COVID-19 hospitalization records in nine states over the summer.

In five Veterans Affairs medical centers, it was also found that protection rates against hospitalizations were 80 percent for people aged 65 and older, compared with 95 percent for those aged between 18 and 64.

U.S. health authorities will review the latest real-world data to decide if booster shots are necessary for all, or at least some Americans, as well as how soon they should be given after the last dose. Food and Drug Administration advisers will publicly debate Pfizer’s application for offering a booster dose in the coming week.