Johnson & Johnson says second dose is 94 percent effective

Johnson & Johnson announced on Tuesday that the protection offered by its COVID-19 vaccine increased to 94 percent when a booster shot was given two months after the initial dose.

According to the company’s Phase 3 study, a two-month booster shot resulted in 100 percent protection against severe cases of COVID-19 and 94 percent protection against symptomatic cases in the U.S.

When a booster shot was administered six months after the initial dose, Johnson & Johnson reported a ninefold increase in antibodies that grew to a 12-fold increase in the four weeks after the injection, regardless of age.

What J&J is saying: “Our single-shot vaccine generates strong immune responses and long-lasting immune memory,” Mathai Mammen, global head of research and development at Johnson & Johnson, said in the company’s announcement. “And, when a booster of the Johnson & Johnson COVID-19 vaccine is given, the strength of protection against COVID-19 further increases.”

The pharmaceutical company also reported that a study had found that a single shot of its coronavirus vaccine was 79 percent effective at preventing COVID-19 infections and 81 percent effective at preventing hospitalizations. This efficacy rate is significantly higher than the 66 percent rate that was shared when the vaccine was first authorized for emergency use.

Context: This announcement from Johnson & Johnson comes shortly after Pfizer’s COVID-19 booster was recommended by a Food and Drug Administration advisory panel for use in people over the age of 65 and those in high-risk groups.

The single-dose Johnson & Johnson vaccine has been the least administered in the U.S. out of the three authorized, making up more than 14.8 million doses out of the U.S.’s total of over 386 million doses.