Sheba Medical Center Clinical Trial Finds Fourth Dose of Pfizer/Moderna Vaccine Offers Limited Protection Against Omicron

Israel's renowned Sheba Medical Center announced on Monday, preliminaryClinical TrialIndicates, the fourth dose vaccinationPfizerOr Moderna's COVID-19 vaccine cannot provide effective protection against the Omicron variant.

Last month, Sheba Hospital launched the vaccination of the fourth type of COVID-19 vaccine for 274 medical workers.Clinical TrialAmong them, 154 people received the Pfizer/BioNTech vaccine, and 120 people received the Moderna vaccine. All of them had previously received three doses of the Pfizer vaccine.

Clinical TrialIt was found that the antibody levels of the two groups of participants were "slightly higher" than last year’s after receiving the third vaccine shot, but unfortunately, the enhanced antibodies could not prevent the spread of Omicron.

Dr. Gili Regev-Yochay, director of the Infectious Diseases Unit at Sheba Medical Center who led the study, said: "Despite higher antibody levels and increased effectiveness against previous variants, the vaccine provides little protection against Omicron."

Preliminary Results Question Israel's Decision to Offer Second Booster (Fourth Dose) to Its Population Aged 60 and Above. The Israeli Government Stated That More Than 500,000 People Have Received the Fourth Dose in Recent Weeks.

Israeli Health Ministry Director-General Nahman Ash stated that this research does not mean the effort to administer a fourth vaccine dose was a mistake. He said, "It restores antibody levels to where they were when the third dose was first administered. This is very important, especially for the elderly."

Israel was one of the first countries to widely vaccinate its population last year and became the first country to offer a vaccine booster last summer. Recently, Israel started administering fourth doses to its elderly population, making it the world's first country to approve a fourth dose.

However, the European Medicines Agency (EMA) warned last week that repeated booster shots could impair individual immune responses, potentially leading to an "overloaded" immune system.

Members of the EMA Biological Health Threats and Vaccine Strategy Committee discussed Israel's decision to offer a second booster dose to the elderly population and medical personnel at a press conference last week, providing recommendations on the use of a fourth vaccine dose.

Subsequently, Marco Cavaleri, head of the EMA Vaccine Committee, warned against overusing booster shots, stating they cannot be "repeated endlessly."

Cavaleri said, "We are quite concerned about the strategy of repeated vaccinations in the short term. We cannot really continue to administer booster shots every 3 to 4 months."

Last week, the World Health Organization also stated that simply repeating booster shots is not the best strategy.

Israel's active promotion of vaccination efforts failed to prevent an outbreak of the Omicron-driven epidemic in the country, leading to record infection levels and sending an increasing number of patients to hospitals, though the number of severe cases remains lower than in previous waves.BioValleyBioon.com）