This week, the Biden government strongly recommended booster vaccinations for most vaccinated Americans, and the Centers for Disease Control and Prevention also published three studies that federal officials said provided evidence that booster vaccinations from Pfizer-BioNTech and Moderna -Coronavirus Vaccines in the Coming Months.
Here’s what we know about booster vaccinations – why Americans might need them and when to get them:
The case for a booster shot
Taken together, the CDC studies show that while the vaccines remain highly effective against hospital admissions and deaths, their bulwark against infection with the virus has been weakened in recent months.
The finding is in line with early data from seven states compiled this week by the New York Times, suggesting an increase in breakthrough infections and a smaller increase in hospital admissions among those vaccinated as the Delta variant spread in July.
The decline in effectiveness against infections may be due to declining vaccine immunity, failure of precautionary measures like wearing masks, or the rise of the highly contagious Delta variant, experts said – or a combination of all three.
Overall, the new studies show that vaccines are about 55 percent effective against all infections, 80 percent against symptomatic infections, and 90 percent or more against hospitalizations, noted Ellie Murray, an epidemiologist at Boston University.