Fourth COVID Shot Triples Resistance to Serious Illness in Over-60s, Israel Finds

Analysis based on data from hundreds of thousands of Israelis shows fourth COVID shot significantly increases protection compared to those who got just one booster

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Passengers on Jerusalem's light train on Thursday.
Passengers on Jerusalem's light train on Thursday.Credit: Emil Salman

A fourth dose of COVID-19 vaccine given to people over 60 in Israel made them three times more resistant to serious illness than triple-vaccinated people in the same age group, Israel's Health Ministry said on Sunday.

This number is based on a comparison with those in the same age group who received a third dose at least four months earlier. The ministry said its analysis was based on statistics on some 400,000 people who had received a fourth shot and 600,000 who had received a third shot. 

The Health Ministry's announcement came after the release of the first large U.S. studies led by the Centers for Disease Control to look at vaccine protection against omicron.

The three studies echoed previous research – including studies in Germany, South Africa and the U.K. – indicating available vaccines are less effective against omicron than earlier versions of the coronavirus, but also that boosters significantly improve protection.

The first study looked at hospitalizations and emergency room and urgent care center visits in 10 states, from August to this month. The booster shot seems to be 90 percent effective against hospitalization with the omicron variant, according to the CDC study. 

The second study focused on COVID-19 case and death rates in 25 states from the beginning of April through Christmas. People who were boosted had the highest protection against coronavirus infection, both during the time delta was dominant and when omicron was taking over as the dominant strain.

The Journal of the American Medical Association published the third study, also led by CDC researchers. It looked at people who tested positive for COVID-19 from December 10 to January 1 at more than 4,600 testing sites across the U.S.

Israel’s COVID cabinet released a statement Saturday night recommending that the green pass is no longer considered a viable indicator of protection. The green pass is Israel’s proof of vaccination allowing citizens to enter public indoor spaces or large gatherings if they have received their third jab of the coronavirus vaccine, or their second dose in the past 6 months.

Due to omicron’s high transmission rate, a negative antigen test should be included along with the green pass before entering public gatherings in order to reduce the variant’s spread.

Additionally, they warned that the quality of care at hospitals in the coming weeks will be reduced due to an influx of infected patients, "Which is expected to worsen due to medical centers’ inability to handle the large case load."

The report continued saying "In the last week, there has been an impression that the ability to care for the community is approaching its limit, therefore, there is a likelihood of an even faster increase in the rate of hospitalization in the coming weeks. Challenges in evacuating members of the community, may result in a longer hospitalization for existing patients.”

Three shots of the Pfizer and Moderna vaccines were about 67 percent effective against omicron-related symptomatic disease compared with unvaccinated people. Two doses, however, offered no significant protection against omicron, the researchers found.

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