As he gingerly lowered himself into a chair after his first coronavirus vaccine jab, Simcha Barlow, a 75-year-old Israeli ultra-Orthodox Jew, said deciding to get inoculated was simple.
"If the rabbis approve, I do not ask any questions at all," the hobbling Torah scholar told AFP at a clinic in the mainly ultra-Orthodox, or haredi, city of Bnei Brak.
Israel's initial vaccination rollout appears to be unfolding successfully, with some two million citizens having received the first of two required injections of the Pfizer-BioNTech jab, a pace widely described as the world's fastest per capita.
Prime Minister Benjamin Netanyahu -- who faces yet another re-election contest and a corruption trial over the coming weeks -- has sought to highlight his personal role in the inoculation campaign.
Netanyahu has in particular emphasised his discussions with executives from Pfizer and Moderna that he says have ensured Israel will have enough supply to vaccinate its entire over-16 population by the end of March.
Media outlets have reported that Israel paid above market price to Pfizer to ensure ample supply. The health ministry declined to comment on those reports.
But experts have said that beyond vaccine procurement, much of the responsibility for the apparently smooth rollout belongs to the country's health funds, known as health maintenance organisations (HMOs).
Israel's four HMOs maintain meticulous information about patients under their care and can deliver health messages to them directly, by text message if necessary, experts said.
Strategies to promote vaccination are tailored to specific communities, which for haredim like Barlow has meant engaging top rabbis from the outset, ensuring they would encourage followers to get the jab.
- Data-driven -
Nationwide, HMOs have been credited with swiftly generating lists of vaccination candidates, organised by priority, and personally contacting them to come for a shot.
And, experts have stressed, a key difference between Israel's uneven coronavirus response and the vaccination effort is that the HMOs, not the government, are leading on inoculation.
"I think the government learnt its lesson and is letting the HMOs do what they know how to do," said Dov Chernichovsky, head of the health policy programme at Israel's Taub Center think tank.
Chernichovsky accused the government of undermining its pandemic response by not relying enough on the HMOs, especially when it came to testing, an area where he said isolating the HMOs was "absurd".
"The state decided not to use the HMOs in the beginning, which was a huge mistake," he said. "Someone came to their senses."
HMO membership is mandatory for all Israeli citizens. People can switch twice a year if they are unsatisfied with their service.
Unlike conventional insurance companies, Israel's HMOs are not-for-profit and play a direct role in medical service delivery, employing doctors and running clinics as well as covering the costs of care.
The operating model was first set up by Jews living in Ottoman-era Palestine, Chernichovsky said.
The chief executive of the Meuhedet HMO, Sigal Regev Rosenberg, said that the detailed information held about patients allowed her organisation to generate vaccination schedules quickly.
"We immediately set up a data system that identified which people to summon as a first priority, who was second priority, and who could wait. The whole thing took 10 minutes," Rosenberg said.
With haredim, HMOs worked with leading rabbis "from the beginning of the operation", she said.
- Palestinians -
However, Rosenberg noted that more work was still required to ensure widespread vaccination among Arab Israelis.
A doctor with the coronavirus unit in Israeli-annexed east Jerusalem, Ali al-Jibrini, told AFP that Palestinians in the area initially had "little interest in getting vaccinated", blaming in part misinformation on social media.
"But there has been something of an awakening and the numbers are starting to increase," he said.
Despite Israel's success in vaccinating its own population, criticism has mounted over the Jewish state's position on the inoculation of Palestinians in the occupied West Bank and Gaza.
Rights groups like Amnesty International have cited international law to argue that, as an occupying military power, Israel must provide vaccines to the entire Palestinian population.
The Palestinian Authority, which controls the West Bank, is pursuing its own procurement options, and on Monday announced contracts with four producers, including the makers of Russia's Sputnik V.
The PA has not publicly asked for Israel's help in securing supply, and neither have the Hamas Islamists, who control Israeli-blockaded Gaza.
Nadav Davidovitch, director of the school of public health at Ben-Gurion University in Beersheba, said supporting Palestinian vaccinations was not only "the right thing to do morally", but was also in Israel's interest.
"We live next to each other, and if we want to create herd immunity, it's important they also get vaccinated," said Davidovitch, who also sits on a panel advising the government on the pandemic response.