The Pfizer BioNTech vaccine achieves 94 percent effectiveness after the second dose, according to the first major “real world” study published on the performance of the injection.
While promising data has been leaking out of Israel for the past few weeks, the Clalit Research Institute released the results of its first detailed and controlled study yesterday (Sunday) covering 1.2 million vaccinated and non-vaccinated person.
Clalit is the largest health care provider in the country, covering more than half of the population of Israel.
The study found that there was a 94 percent reduction in the rate of symptomatic diseases and a 92 percent reduction in the rate of serious illness in those who received the vaccine, compared with 600,000 who were not vaccinated.
Importantly, vaccine efficacy was maintained in all age groups, including those over 70 – an age group where vaccine efficacy could not be evaluated in Pfizer’s original clinical trials due to inadequacy. in this participating age group.
Clalit reported a high vaccine efficacy of 91 to 99 percent over a period of seven days or more after participants received the second dose of the vaccine and were considered “fully vaccinated”. The researcher said they expected this to rise further as more data over seven days flowed in.
Dr. said. Ran Blitzer, director of the Clalit Research Institute, said: “Pfizer ‘s Corona vaccine is clearly the most effective in real life a week after the second dose, just as it was found in the [original] clinical study.
“Furthermore, the trends we are indicating indicate that continued follow-up for additional weeks after the second dose will significantly increase the effectiveness of the vaccine measurement. In fact, in a preliminary study, we indicate an even higher efficacy for the prevention of infectious and serious disease among vaccines after 14 days ”.
Clalit is expected to publish its findings in full over the next few weeks in a major medical journal. Some expect it to also publish results on the extent to which the Pfizer vaccine is blocking the spread of the virus – and there are rumors that these data are also very positive.
It is difficult to maintain the true efficacy of the vaccine due to difficult reasons including a third lockout and a violent outbreak of the virus in Israel.
The Clalit study overcame this by matching all vaccinated subjects with a non-vaccinated individual with relatively similar conditions.
“The vaccine group was tested against a control group of around 600,000 unvaccinated people who have been carefully modified to test each vaccine for a similar non-vaccine in a long series of symptoms such as the level of risk of infection, the level of risk of developing a serious disease, health status and more, ”Clalit said in a news release.
“The creation of the control group was dynamically controlled so that people could be removed and transferred between the groups if their immunization status changed over time.
“This type of enumeration, which gives a complete and timely appearance to the area and personal characteristics between the vaccinated and the non-vaccinated at any given time, allows for the impact of simultaneous events. normalize – such as quarantine effects, and changing vaccine contraindications ”.
No data were published on the efficacy of the vaccine after the first dose. Most of the data coming out of Israel a few weeks ago suggests that the protective effect of the injection only begins firmly after the second dose.
Last week the scientist BioNTech behind the Pfizer vaccine warned that the gap between doses should not exceed six weeks.
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