Even a fourth dose of a Covid vaccine isn't enough to stop people getting infected with Omicron, according to the preliminary results of a trial.
The study of more than 270 medical staff in Israel found the fourth shot only raised antibodies 'a little' compared to those who were triple-vaccinated. Participants given four doses were only 'a bit less' likely to test positive for the mutant strain than those who had received three. -- More...