People who have been vaccinated with the Pfizer or AstraZeneca vaccines and who become infected with the delta variant of the coronavirus can transmit the virus, as can unvaccinated people. Also, the effectiveness of vaccines diminishes after a few months, according to large-scale research from the University of Oxford.
Someone who has been vaccinated and yet has been infected with the delta variant sometimes has as many virus particles as someone who is not vaccinated. Mass vaccination normally ensures that a virus can no longer circulate and becomes extinct, after which herd immunity develops. This now seems unlikely, the researchers say.
Hundreds of thousands of people have been tested with, among other things, cotton swabs in recent months for research. This showed, among other things, that people who have already been vaccinated sometimes have as much virus in their throats as unvaccinated people. This means that vaccinated people can be just as contagious as those who have not been vaccinated.
Vaccine efficacy is lower but still good
The same research also shows that the effectiveness of vaccines against the delta variant decreases over time. Where it was first assumed that the Pfizer vaccine still prevents about 88 percent of all infections with the delta variant, and the AstraZeneca vaccine 67 percent, Pfizer is still 75 percent effective after four to five months. after vaccination: comparable to AstraZeneca. According to the scientists, this is still “at least as good as protection after a natural infection.”
Extra booster shot
Simon Clarke of the University of Reading, an expert who was not involved in the study, believes that an additional booster shot is necessary for winter, at least for the most vulnerable. More and more experts think like this.
The Health Council is expected to issue an advisory report on this next month.