According to a new study, as the Delta variation of coronavirus became the prevalent strain in the United States, all three COVID-19 vaccinations available to Americans lost some of their protective effect, with vaccine efficacy among a large group of veterans declining between 35 and 85 percent. In early March, just as the Delta variety was acquiring a foothold across American communities, researchers analysed the data of almost 800,000 U.S. veterans and discovered that the three vaccines were roughly similar in their effectiveness to prevent illnesses. But that altered substantially during the next six months.
Moderna’s two-dose COVID-19 vaccine, which was 89 percent effective in March, was just 58 percent effective by the end of September. In the same time frame, the efficiency of Pfizer and BioNTech vaccines, which also used two doses, dropped from 87 percent to 45 percent. Over the course of those six months, the protective power of Johnson & Johnson’s single-dose vaccine dropped from 86 percent to just 13 percent.
When compared to uninfected veterans of the same age, those who got a “breakthrough” infection after receiving the Moderna vaccination were 76 percent less likely to die from COVID-19. Veterans who received the Pfizer-BioNTech vaccination and then developed a breakthrough illness were 70% less likely to die than their unvaccinated counterparts. When older vets who received a single J&J vaccination injection developed a breakthrough illness, they were 52 percent less likely to die than those who did not receive any shots.