Pfizer is using Israel to test its vaccine – here’s what it shows

Israeli researchers have found that having a single injection of Pfizer’s coronavirus vaccine can reduce viral loads, making it difficult to transmit Covid-19 if someone becomes infected after the first dose.

And it’s not the only positive Pfizer jab research to come out of Israel recently.

Another independent Israeli study, from the country’s largest healthcare provider, Clalit, found a 94 percent drop in symptomatic Covid-19 infections among 600,000 people who received two doses of the Pfizer vaccine.

The researchers also found that the fully inoculated group was 92 percent less likely to develop serious illness from the virus.

Pfizer has said its vaccine, which started rolling out in New Zealand for vaccinators and border workers on Friday, needs two doses taken 21 days apart to be effective.

Why do we receive so much Israeli data?

Nigel McMillan grew up in Timaru, and is a professor of infectious diseases and immunology at the Menzies Institute of Health at Griffith University in Queensland, he said it was not surprising that there was an influx of information about the Pfizer jab leaving Israel.

Pfizer’s option was the first coronavirus vaccine in the world to pass phase three of the tests, explained Professor McMillan, which meant it was out of use in the community.

And Israel has already administered more than 6.7 million doses, according to Bloomberg’s Covid vaccine tracker.

This high vaccination rate and the fact that each citizen has a digital health record made it easier for the country to collect and compare information.

“Because [Israel] it’s vaccinating a lot of people, it allows them to compare unvaccinated and vaccinated people, “said Professor McMillan.

Pfizer has entered into an agreement with Israel’s Ministry of Health to obtain anonymized data on vaccine recipients, an agreement that the company describes as a “non-interventionist collaboration of collecting data from ‘real world’ evidence”, rather than from a clinical research study.

Decrease in viral load after a vaccine.

The first study, which found reduced viral loads after the first dose of Pfizer, retrospectively examined the test results of 2,897 patients.

“What this shows is that if you are vaccinated, even with a single dose, and immunity is not expected to kick in for at least seven to 10 days … you have less virus in nasal swabs,” said Professor McMillan.

“So you have about four times less virus,” he said, adding that this meant that the infected person was less likely to transmit the virus.

Peter Collignon, professor of microbiology and infectious diseases at the Australian National University, said the results weren’t entirely surprising.

“Each vaccine at least reduces the severity of the disease and therefore the amount of virus that is likely to be shed,” he said.

“The Pfizer Vaccine [impact on disease severity] So far it looks the most promising so I’m not surprised by the evidence that it has an impact on transmission.

But the data has its limitations. It has not yet been published or peer-reviewed and does not include data on what happens after the second dose of Pfizer.

“It’s certainly an encouraging trend; if one dose reduces it four times, you would expect two doses to reduce it even more,” said Professor McMillan.

“We are really interested in the idea that transmission can be prevented, because this is an important issue in terms of how quickly things could get back to normal.”

And while Pfizer welcomed the initial findings, the company made it clear that two doses of the vaccine were required to provide the 95 percent efficacy rate seen in its phase three trial, and more research was needed to better understand the transmission.

Decrease in symptomatic Covid-19 infections

Meanwhile, Clalit’s study found a 94 percent drop in symptomatic Covid-19 infections among 600,000 people who received two doses of the Pfizer vaccine.

Professor McMillan said that although he had not seen the study data set, it would be a positive step if the results were replicated in all recipients of the vaccine.

“That means the virus will basically not be able to circulate in the community, it will allow things to go back to normal,” he said.

The data behind this second study has yet to be made public.

Even Pfizer says it has yet to see Clalit’s published research, but “looks forward to those results.”

Professor McMillan said that during the pandemic, it was common for research to be published in its early stages because health experts and the wider community were eager to examine any new findings.

However, he argued that the “gold standard” of scientific research was data that had been peer-reviewed and published.

-ABC