7 recent COVID-19 vaccine study findings

Seven study findings on how COVID-19 vaccines respond to the delta variant of the coronavirus, mixing and matching types of COVID-19 vaccines and more, as reported by Becker's Hospital Review in the last two weeks:  

1. Pfizer's COVID-19 vaccine was 97 percent effective against severe disease and 83.7 percent effective against infection six months after the second dose in a study consisting of data from 42,000 people in six countries. 
   
   

2. A third dose of Pfizer's COVID-19 vaccine "strongly boosts" the body's immune response against the delta variant of the coronavirus, Pfizer said, citing data showing that antibody levels against the delta variant were five times higher in people ages 18 to 55 after a third dose, and 11 times higher in 65- to 85-year-olds.
   
   
3. Antibody levels in people who received one dose of AstraZeneca's COVID-19 vaccine followed by one dose of Pfizer's shot were six times higher than those who received two doses of AstraZeneca's shot in a study conducted by the Korea Disease Control and Prevention Agency in South Korea involving 499 medical workers.
   
   
4. Pfizer's COVID-19 vaccine was 39 percent effective at preventing COVID-19 infection and 88 percent effective against hospitalizations from the virus in Israel, according to a study based on an unspecified number of people from June 20 to July 17. The study also showed the shot was 91 percent effective against severe illness from COVID-19.
   
   
5. Two doses of Pfizer's COVID-19 vaccine were 88 percent effective against symptomatic disease from the delta variant of the coronavirus in a study conducted by Public Health England. It also found that AstraZeneca's vaccine was 67 percent effective against the delta variant. Both shots were far less effective after only one dose, about 30 percent effective.
   
   
6. Johnson & Johnson's COVID-19 vaccine may be much less effective against the delta and lambda variants of the virus compared to the original strain, according to a study conducted by researchers from NYU Grossman School of Medicine in New York City and posted on the preprint server bioRxiv.