Israel is pressing ahead with a campaign to offer coronavirus boosters to almost anyone aged over 12.

Authorities said this approach has been further vindicated by a US decision to give the booster jabs to older patients or those at higher risk.

Israeli officials credit the booster campaign, which has already been delivered to about a third of the population, with helping to suppress the country’s latest wave of Covid-19 infections.

They say the differing approaches are based on the same realisation that the booster is the right way to go, and expect the US and other countries to expand their campaigns in the coming months.

“The decision reinforced our results that the third dose is safe,” said Dr Nadav Davidovitch, head of the school of public health at Israel’s Ben-Gurion University and chairman of the country’s associationof public health physicians. “The main question now is of prioritisation.”

The World Health Organisation (WHO) has called for a moratorium on boosters until at least the end of the year so that more people in poor countries can get their first two doses, but Israeli officials say the booster jab is just as important in preventing infections.

“We know for sure that the current system of vaccine nationalism is hurting all of us, and it’s creating variants,” said Dr Davidovitch, who is also a member of an Israeli government panel of experts.

But he added that the problem is “much broader than Israel”.

Israel raced out of the gate early this year to vaccinate most of its adult population after striking a deal with Pfizer to trade medical data in exchange for a steady supply of doses. It has also purchased large quantities of the Moderna and AstraZeneca vaccines.

Most adults had received two doses of the Pfizer vaccine by March, causing infection levels to plummet and allowing the government to lift nearly all coronavirus restrictions.

But in June, the highly infectious Delta variant began to spread. After studying the matter, experts concluded that the vaccine remained effective against the virus, but that its efficacy waned roughly five months after the second jab.

In late July, Israel began distributing booster jabs to at-risk citizens, including those aged over 60. Within weeks, it had expanded the campaign to the general population.

More than three million of Israel’s nine million citizens have received a third dose of the Pfizer vaccine, according to the health ministry.

In a study published last week in the New England Journal of Medicine, Israeli experts said that in people who had been vaccinated five months earlier, the booster increased vaccine efficacy tenfold compared with vaccinated patients who did not receive it.

That study tracked about one million people 60 and older and found that the booster was “very effective at reducing the rate of both confirmed infection and severe illness”, the health ministry said.

A senior Israeli health official, Dr Sharon Alroy Preiss, was among the experts testifying before the US Food and Drug Administration panel last week in favour of the booster jab.

But the regulator decided against boosters for the general population, opting only to authorise it for people aged 65 or older and those in high-risk groups.

Experts cited a lack of safety data on extra doses and also raised doubts about the value of mass boosters, rather than ones targeted to specific groups. The US Centres for Disease Control and Prevention made a similar endorsement on Thursday.

The Israeli health ministry said the FDA decision “gave validity to the third vaccine operation” under way in Israel, which “decided to act responsibly and quickly in order to treat growing infections.”

It said statistics show the booster dose has “restored protection”.

Dr Ran Balicer, head of the government’s expert advisory panel on Covid-19, said recent weeks have seen “a declining rate of new infections among the elderly”, the vast majority of whom have received booster jabs, and “a continuous increase in the proportion of unvaccinated individuals within the new severe cases”.

In recent weeks, as the booster campaign has been rolled out, the percentage of unvaccinated among serious Covid-19 cases has climbed, and the overall new cases among people with at least two shots has dropped.

As of Friday, around 70% of Israel’s 703 serious cases of Covid-19 were among the unvaccinated, and about 20% had not received a booster.

A month earlier, after Israel vaccinated 1.5 million people with a third dose, those two groups were equally represented among the serious cases.

More than 60% of Israelis – the overwhelming majority of the adult population — have received at least two doses of the coronavirus vaccine.

Some experts noted that the US and Europe were several months behind Israel’s vaccination campaign and predicted those countries would follow suit in the months ahead.