- Rachel Streier
- Health correspondent
Israel obtained large quantities of the Coronavirus vaccine from the Pfizer company in exchange for it as a global test field in this field.
Israel is at the forefront of countries that launched a large-scale vaccination campaign for its citizens and succeeded in vaccinating a large proportion of the population within a short period.
Scientists are watching the data presented by Israel with interest, to see how effective the vaccine is when administered to the entire population.
Therefore, there was justified concern when the Israeli coordinator on the Covid 19 epidemic, Professor Nahman Ash, said that one dose of Pfizer vaccine, contrary to what the reports indicate, may not be sufficient.
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In response to Ash’s statements, the Israeli Ministry of Health said: “The statements of the Commissioner for Covid-19 about the effect of the first dose of the vaccine were taken out of context and therefore inaccurate.”
The ministry said that the commissioner said: “We have not yet witnessed a decrease in the number of people infected with this virus who suffer from serious symptoms. It is expected that we will see the complete protection provided by the vaccine soon.”
After the vaccine is given, the body needs time to recognize the genetic material of the virus, and create an immune response (the production of antibodies and T cells that prevent the virus from entering the cells and kill the infected cells).
And immunologists, such as Professor Danny Altman, of Imperial College London, say it takes at least two weeks for the vaccine to take effect.
Some patients who were recently admitted to hospital due to the Corona virus had received the first dose of the vaccine recently, and this does not necessarily mean that the vaccine is not effective.
Given the time it takes the body to create immunity against the virus after vaccination, exposure of unvaccinated people to the virus, and the incubation period required for symptoms of the disease to appear, the effect of the vaccine will not be evident in the national statistics on the disease status before a month has passed.
Clalit, the largest healthcare agency in Israel and whose services include most of the population of Israel, compared the medical records of 200,000 people over the age of 60 who had received the vaccine with a similar number of people who had not received the vaccine.
During the two-week period after the first dose was taken, the rate of infection with the virus in the two groups with the virus was approximately equal, but after that, the rate of new infections among the group that received the vaccine decreased by 33 percent.
“This is a very early protection, and there is actually a 33 percent decrease,” said Ran Paletcher, a professor of public health advising the government and chief innovation officer at Clalit.
After that, the number of cases began to decline and became so limited that its percentage could not be determined.
Professor Stephen Evans, a professor at the London School of Hygiene and Tropical Medicine, said: “It is not reasonable to determine the efficacy of a vaccine based on this type of observational study subject to many biases, with those derived from randomized trials (such as those that were initially tested for the vaccine).
But early evidence points to roughly the same trend that has been seen in Pfizer’s clinical trials of tens of thousands of people.
In these trials, the rates of new infection were varied in both the vaccinated and the control groups after two weeks.
This gap continued to widen more than 100 days after the first dose.
Israel began the vaccination campaign on December 19, and by the end of 2020, 10 percent of its population had vaccinated.
The number of those who received the second dose was about half a million people out of a total population of 9 million.
The effect of the vaccine is expected to appear this week in terms of the number of severe cases of the virus, according to Professor Paletcher.
Pfizer hopes that two doses of its vaccine will provide 95 percent protection against infection. And even vaccines that have less effectiveness, can protect people with this virus from the risk of death.
The annual influenza vaccine is effective only 40-60 percent, but it prevents hundreds of thousands of deaths annually.
A fatal disease
Professor Evans says: “The effectiveness of the vaccine against Covid 19 may be less important as long as the vaccine is certain of death or does not require the patient to be hospitalized.”
The vaccine aims to protect people from the dangerous symptoms of the disease and avoid taking them to hospitals, and this is more important than the rate of infection itself.
For example, the Clalit data does not differentiate mild or asymptomatic infections from more severe or even fatal infections.
And the UK came to the conclusion that more lives could be saved by giving one dose to as many people as possible instead of giving two doses that would guarantee maximum protection for fewer people.
Professor Evans said: “The reports received from Israel are insufficient to provide any evidence that the UK’s current policy of delaying the second dose of vaccines is in any way true.”