Giving repeated booster doses of existing covid-19 vaccines in developed countries is not a sustainable global strategy, says Instead, the focus should shift towards producing new vaccines that work better against transmission of emerging variants The World Health Organization (WHO) has also warned repeatedly against boosters while a high percentage of people in low and middle-income countries – estimated to be over 40% of the world’s population – are unvaccinated, fearing boosters will lower the number of vaccine doses available to these countries. Instead, the agency recommended that boosters should be tied to the cold season with longer intervals. Meanwhile, the European Medicines Agency (EMA) cautioned last week that there was no evidence to back a fourth booster, warning that repeat boosters every four months might actually weaken people’s immune systems.īoosters “can be done once, or maybe twice, but it’s not something that we can think should be repeated constantly,” said Marco Cavaleri, the EMA head of biological health threats and vaccines strategy, said at a press briefing last week, as reported by Bloomberg. In addition, around the same percentage of hospital workers who received the fourth dose caught the virus as those who didn’t get the fourth booster. It’s nice, but it’s not what we expect from a booster.” Last week, she told Israeli Prime Minister Naftali Bennett that there had been a five-fold increase in antibodies in people who took the fourth dose, but she later told a radio station that “the amount of antibodies returns to the level it was after the third vaccine, not more. ”Maybe there are a few more antibodies but not much more compared to the third dose,” said Regev-Yochay. They were matched with a control group of around 6,000 health workers who have been being followed by the hospital since the start of Israel’s vaccination campaign in December 2020.Īccording to Regev-Yochay, the third dose resulted in “much higher antibodies, neutralization and the antibodies were not just higher in quantity but also in quality” than the second dose – but the fourth vaccine did not show significant antibody increase. A week ago, 120 healthworkers received a shot of Moderna following three doses of Pfizer one week ago. Some 154 health workers at Sheba Medical Center received their fourth Pfizer shot two weeks ago. “Despite a significant increase in antibodies after the fourth vaccine, this protection is only partially effective against the Omicron strain, which is relatively resistant to the vaccine,” lead researcher Prof Gili Regev-Yochay, told a media briefing on Monday. An Israeli woman gets a COVID-19 vaccine.Ī fourth COVID-19 booster mRNA vaccine has proven ineffective against Omicron infection, according to preliminary research from Israel released on Monday.

Focus booster reporting