Two-dose J&J vaccine proves 94 pc effective against symptomatic COVID-19

Moscow, Sep 21 (Agency) The US pharma giant Johnson & Johnson said on Tuesday that a Phase 3 study proved that its single-dose vaccine gave 94% protection against symptomatic COVID-19 disease when coupled with a booster shot administered two months later.

“Our single-shot vaccine generates strong immune responses and long-lasting immune memory. And, when a booster of the Johnson & Johnson COVID-19 vaccine is given, the strength of protection against COVID-19 further increases,” the company’s R&D chief Mathai Mammen said.

The company said that antibody levels rose from four to six times higher after a booster shot was given two months after the first dose, compared to antibody levels observed after the first shot. When administered six months after the first shot, the booster increased antibody levels ninefold within one week. Antibodies continued to climb to twelve-fold four weeks after the booster.