The second dose of Johnson & Johnson, given two months after the first, provides one “stronger protection” from Covid: the company itself made it known, as reported by the Messenger. A not insignificant novelty, given that so far only one dose of this drug has always been injected, the only single dose of all those we know, such as Pfizer, Moderna and AstraZeneca. Also, compared to Pfizer and Moderna, the J&J vaccine has always had slightly lower efficacy. The peak effectiveness of the first two, in fact, was respectively 95% and 94% against symptomatic disease.
It is now known that J&J is also able to provide higher protection, but with the two doses. The company said that two injections, administered two months apart, produced an equally high level of effectiveness: 94% protection against any symptomatic infection in the United States and 100% against serious diseases. The new data can now influence regulators’ decision on a possible second dose for the nearly 14.9 million people who have received Johnson & Johnson.
The new evidence on this preparation, however, raises some questions about the timing. That is to say, when it is better to start administering a second dose. According to the most recent data, in fact, the recall two months later led to a marked increase in antibody levels. But according to previous data, already published, a booster dose given six months after the first would lead to even higher antibody levels. “With the two-month booster interval, the antibodies increased four times. But when a booster was given after six months, it resulted in a 12-fold increase,” he explained. Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center, whose lab helped develop the J&J vaccine.