169
For the first time in the world, Israeli researchers from Sheba Medical Center tested the fourth dose of the Covid vaccine to test its safety and efficacy. They put 150 healthcare workers on the second Pfizer or Moderna booster, whose antibodies had started to drop after the third injection in August – their vaccination campaign started much earlier than in Italy – and showed that the fourth dose actually increased to to five times the level of neutralizing antibodies, but their level, however high, is proving ineffective at countering Omicron alone.
.