JERUSALEM (AFP) – Israel’s health ministry on Thursday authorised a fourth vaccine shot for people with weakened immune systems to help confront rising COVID cases driven by the highly infectious Omicron variant.

The approval came as another anti-weapon arrived in the country: a first shipment of Pfizer’s anti-COVID pills.

“Today I approved giving the fourth vaccine for immunocompromised people,” Health Ministry Director General Nachman Ash told reporters.

“I did this in light of studies that show the benefit of the vaccine, including the fourth vaccine, to this population, and in light of the fear they are more vulnerable in this outbreak of Omicron.”

The announcement came as health authorities reported more than 4,000 new cases on Thursday, a high not seen since September.

Health Minister Nitzan Horowitz said Israel was in “a fifth wave”, with most cases probably related to the Omicron variant.

Earlier Thursday, an El Al flight from Belgium landed in Tel Aviv carrying a shipment of Pfizer’s anti-COVID pill, which Prime Minister Naftali Bennett hailed as an “important addition to the arsenal in the war against the pandemic”.

“Thanks to our rapid action, the drugs have arrived in Israel quickly and will assist us in getting past the peak of the coming Omicron wave,” Bennett said.

The US Food and Drug Administration last week authorised Pfizer’s Paxlovid pill for high-risk people aged 12 and up.

In trials, the treatment has been shown to reduce COVID hospitalisations and deaths by 88 per cent among at-risk people.

The oral treatments block the virus’ ability to replicate and should withstand variants, experts say.

Until now, the main treatments for COVID have been synthetic antibodies or Gilead’s antiviral remdesivir, which are administered by infusion.

The United States has paid $5.3 billion for 10 million courses of Pfizer’s new treatment, as well as $2.2 billion for treatment from rival Merck, whose pill appears to be less effective.

The European Union’s drug regulator has also allowed member states to use Pfizer’s COVID medications ahead of formal approval as an emergency measure.

Ran Balicer, chairman of Israel’s national expert panel on COVID-19, said the drug could “dramatically reduce risk of severe illness, potentially thus also reducing the overall hospital burden”.

He said the medications were critical, “in addition to vaccines and masks.”

Ash approved the booster days after Israel’s Sheba Medical Centre launched a clinical trial Monday, giving 150 staff members a fourth jab to test the benefit of a wider national roll-out of additional doses.

Israel was one of the first countries in the world to offer a third shot to the general public.

Some 4.2 million people out of a population of 9.4 Israelis have got three shots of coronavirus vaccine.