The Israeli Ministry of Health announced today that the “Green Pass” for vaccinated expires when 6 months have passed after the second dose and now also 6 months after the third (“booster”) vaccination.

Israel, which has mainly used the Pfizer-BioNTech vaccine in its rollout, started offering booster doses in July to people over 60 years old in response to an uptick in cases. In late August, the government made booster shots available to anyone at least five months after their second jab.

Israel so far has administered more than two million booster shots, and the government has said it is preparing to ensure it has sufficient supplies in case a fourth dose is needed.

Is protection from vaccines falling?

Several studies into so-called breakthrough infections in the US have suggested there is a reduction in vaccine effectiveness against infection over time.

New data released by Moderna this week suggested that the protection given by its COVID vaccine wanes over time. The company’s analysis, which was yet to be peer reviewed, found higher rates of infection among groups who were vaccinated more than one year ago compared with those who were vaccinated eight months ago.

Pfizer has said data from its own early clinical trials suggested that vaccine efficacy declines after participants received their second dose and that a booster shot was safe and helped to restore antibody levels.

‘Too soon to know’ how beneficial a COVID-19 booster shot may be

Researchers from Israel told a panel of U.S. vaccine experts weighing a potential Covid-19 booster dose from Pfizer Inc. and BioNTech SE on Friday that it’s unclear how long the benefit of such a shot would last.

Dr. Peter Marks, one of the FDA’s top officials, acknowledged on Friday that there are different opinions on the necessity of booster shots and urged panelists to consider the current dynamics of the outbreak in the United States.

When asked by members of a Food and Drug Administration advisory panel whether more shots would be needed to keep Covid-related illness away, the Israeli scientists said it was simply too soon to know.

“This is very early, we can’t really tell,” said Sharon Alroy-Preis from the Israel Ministry of Health. “It is not really clear where this is going.”

CDC: Vaccine protection against Covid-19 wanes over time

The protection provided by Covid-19 vaccines appears to wane over time, especially for people 65 and older, a US Centers for Disease Control and Prevention expert said Wednesday.

Ruth Link-Gelles, who helps lead the CDC’s Vaccine Effectiveness Team, reviewed a series of studies looking at the overall effectiveness of vaccines in various groups between February and August and found similar patterns for Pfizer’s and Moderna’s vaccines, both made using mRNA.

Effectiveness started to wane a few months after people were fully vaccinated — defined as two weeks after their second dose of either vaccine.

“For individuals 65 plus, we saw significant declines in VE (vaccine effectiveness) against infection during Delta for the mRNA products,” Link-Gelles told the a meeting of CDC vaccine advisers.

“We also saw declines, particularly for Pfizer, for 65 up, that we’re not seeing in younger populations. Finally there’s evidence of waning VE against hospitalization in the Delta period,” she said.

The CDC’s Advisory Committee on Immunization Practices met Wednesday to discuss the potential need for booster doses of vaccines.