Waning Omicron Defense Prompts Need for Fourth Shot, Israel Says

(Bloomberg) -- Omicron’s fast spread could leave the population almost unprotected against Covid infection, prompting a decision to offer some people fourth vaccine doses, according to the Israeli Health Ministry. 

The transition to omicron from delta would leave the population age 60 and over with only 25% protection against infection within a month, compared with 75% today, according to the ministry. Officials released a presentation backing their decision earlier this week to offer a fourth shot to people in that age group as well as medical personnel. 

Booster shots that are not “fresh” -- that is, those that have been given three to four months ago -- have low effectiveness in preventing infection, the ministry said.

A fresh dose of the Pfizer Inc. vaccine would raise protection to 70%-90% for the first month, and 50%-70% for the second month, easing the strain on hospitals, according to the presentation.   

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