The pharmaceutical company Johnson & Johnson published study results on Tuesday, according to which a second dose of its Janssen corona vaccine significantly improves the protective effect.
According to the data, double vaccination protected people in the United States 94 percent from moderate Covid-19 disease and 100 percent from serious illness.
The results have not yet been verified by independent scientists and are subject to uncertainty.
So far, the Johnson & Johnson vaccine has only been administered once because, according to the approval studies, its effectiveness is sufficient after just one dose: The RKI states (p. 37) that the vaccine in the population worldwide is 66.9 percent before Covid-19 protects (it was even more effective in the study arms in the USA) and offers 76.3 percent protection against Covid-19 in the over 60 age group.
Because of the single dose, Johnson is also increasingly used for people who are difficult to reach for a second vaccination - for example when mobile vaccination teams are deployed to immunize the homeless or people in socially deprived areas.
Vaccination protection disappears less
The Johnson & Johnson vaccine is a vector vaccine. It contains a harmless virus that introduces parts of the coronavirus blueprint into the body. These prepare the immune system for the real pathogen. The mRNA vaccines from Biontech / Pfizer and Moderna are known to deteriorate over time and to decrease antibody levels in the blood. In the case of the J&J vaccine, this effect may be somewhat smaller, as a study with around 390,000 vaccinated and 1,524,000 unvaccinated participants, which has also not yet been tested, shows.
In order to analyze whether and how the protective effect can be increased by a Janssen booster vaccination, more than 30,000 participants worldwide are currently being examined in the so-called Ensemble 2 study. The subjects receive either a second vaccination or a placebo injection after eight weeks. According to the Johnson & Johnson researchers, the interim results of the ongoing Ensemble 2 study show that the concentration of antibodies formed after the second vaccination is four to six times higher than after just one dose. That explains the higher protective effect.
However, many people who received the J&J vaccine were vaccinated much longer than eight weeks ago.
According to the company, the antibody titers increase even more after a longer vaccination interval, namely by nine to twelve times if the second vaccination dose is administered six months after the first.
4.4 million Janssen cans in Germany
A few days ago the American FDA recommended that people over 65 years of age and patients at risk for a severe Covid course be given a booster vaccination with the vaccine from Biontech / Pfizer; there is no recommendation for the Johnson & Johnson vaccine.
To date, 221.4 million doses of Biontech, 150 million doses of Moderna and 14.9 million doses of Johnson & Johnson have been administered in the United States.
In Germany, the Janssen vaccine, which has been approved since May 10, 2021, plays an even smaller role in relative terms: by the end of calendar week 37 on September 19, 2021, 4,426,775 doses of Johnson & Johnson had been delivered. For comparison: The manufacturers Biontech / Pfizer had delivered 85,151,550 cans, AstraZeneca 14,425,320 cans and Moderna 12,836,080 cans.
Stiko recommends Janssen for people older than 60 years because younger patients have - very rarely - developed blood clotting disorders with the formation of cerebral vein thrombosis in combination with a lack of blood platelets.
Most recently, there were reports of vaccination breakthroughs, which apparently occur more frequently after a Janssen vaccination.
According to the RKI, a good three million people have received a Johnson & Johnson vaccination so far.
For every million people vaccinated, there would be a rough estimate of 2000 vaccination breakthroughs.