Studies in Israel have offered tentative optimism on the effectiveness of vaccines in curbing the coronavirus pandemic, with initial data suggesting even the early stages of inoculation campaigns might have marked decreases in both hospitalisations and infections.
With one in three Israelis having received at least one shot, a far higher fraction than anywhere else, the country of 9 million people provides a test case for the worldwide vaccine push.
The state’s 24/7 campaign has meant many vulnerable populations, including around 70% of over-60s, have already received the prescribed two doses of the Pfizer/BioNtech vaccine. Currently, the country is injecting up to 200,000 people a day, and last week made the jab available to anyone over 35. Secondary school students aged 16 to 18 are also included, in the hopes of allowing them to sit exams.
Israel’s health ministry released its first official results last week, showing that only 317 out of 715,425, or 0.04%, of people became infected a week after becoming fully vaccinated against the disease – the time when increased immunity is expected to kick in. Of the vaccinated people who were infected, 16 had to be hospitalised, or 0.002% of the total.
One domestic healthcare provider, Maccabi Healthcare Services,, released a smaller study on Thursday that also raised spirits. It revealed that out of 163,000 Israelis given both shots, only 31 were infected, compared with nearly 6,500 infections among a control group of unvaccinated people.
Maccabi said the data suggested the vaccine was 92% effective, close to the 95% efficacy that Pfizer claims. “This is very, very good news,” Dr Anat Ekka Zohar, the vice-president of Maccabi, told local media.
Israel’s government has capitalised on its ability to run a rapid vaccination campaign, and analyse its impact on infections in real time, to persuade Pfizer to keep it steadily supplied with doses.
Earlier this month, the prime minister, Benjamin Netanyahu, said he had secured a commitment from the pharmaceutical company to bring forward deliveries in return for Israel providing “statistical data” – in effect making the country a mass test case to see how vaccines might halt the pandemic.
The country hopes to have vaccinated all over-16s by the end of March, and possibly earlier. However, experts have cautioned that data from Israel is preliminary and could be misleading. With its vast variables and constantly changing scenarios, an entire society cannot act as a petri dish for a vaccine trial, they say.
“When you vaccinate nationwide, there’s lots of confounders,” said Eran Segal, a computational biologist at the Weizmann Institute. “This is not a trial. That’s the problem. We should be very cautious.”
Israel is currently up againsy a debilitating third wave of infections, with a national lockdown unable to significantly push down death rates. The government blames high infection rates on the more transmissible British variant of the virus.
Vaccine data could be influenced by both the lockdown, which may decrease infections, and the British variant, which likely has the opposite effect, in confusing and contrasting ways.
Meanwhile, the first people to receive the vaccine mostly come from vulnerable populations, who may have been more likely to take precautions, which also could skew the data. Preliminary research might show different results at different times as the number of people being vaccinated is continually changing, and hospitalisation usually occurs days after infection.
An intense global focus on signals from Israel has already led to controversy. Several million Palestinians living under Israeli occupation have not been vaccinated. On Sunday, Israel’s defence ministry said it had agreed to send 5,000 doses to immunise frontline Palestinian medical workers, a move that followed international pressure.
Separately, earlier this month, the country’s “coronavirus tsar” raised concerns that one shot of the Pfizer vaccine might be less effective than originally thought. The comments made news in the UK, where the government faces concerns that a policy to delay administering their second doses could backfire. However, Israel’s health ministry later said the comments had been taken out of context.
Last week’s health ministry figures may provide further concern for the UK policy. It showed that 42% of Israel’s 834 critically ill patients had already received one shot of the Pfizer vaccine. That figure dropped to 2% after the second jab.
While acknowledging the limitations of data coming out of Israel, Segal does see possible hope in one potential key indicator – the percentage of people over 60 who have become critically ill. As a fraction of the total population, that group, which has largely been vaccinated, is decreasing, a trend not seen during previous lockdowns when inoculations were unavailable.
“There are definitely some positive indications,” he said. “We should begin to see numbers going down, both critically ill and infections. Definitely the critically ill.”
