The protection that a Pfizer booster shot gives against the new coronavirus variant Omicron, following a “Pfizer primary course,” drops to just 45% after 10-plus weeks, according to a new study.
A booster shot from Moderna fared better, the study from the United Kingdom Security Agency (UKSA) said.
“In all periods, effectiveness was lower for Omicron compared to Delta,” the report said. “Among those who received an AstraZeneca primary course, vaccine effectiveness was around 60% 2 to 4 weeks after either a Pfizer or Moderna booster, then dropped to 35% with a Pfizer booster and 45% with a Moderna booster by 10 weeks after the booster. Among those who received a Pfizer primary course, vaccine effectiveness was around 70% after a Pfizer booster, dropping to 45% after 10-plus weeks and stayed around 70 to 75% after a Moderna booster up to 9 weeks after booster.”
“These results should be interpreted with caution due to the low counts and the possible biases related to the populations with highest exposure to Omicron (including travelers and their close contacts) which cannot fully be accounted for,” the report said. – READ MORE