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Covid-19: Booster dose reduces infections and severe illness in over 60s, Israeli study reports

BMJ 2021; 374 doi: (Published 17 September 2021) Cite this as: BMJ 2021;374:n2297

Rapid Response:

Re: Covid-19: Booster dose reduces infections and severe illness in over 60s, Israeli study reports

Dear Editor

I have followed covid-19 statistics of several countries during the pandemic, including Israel.

In Israel the number of deaths averaged about 1 to 2 per day during the weeks before July 30, when the booster vaccination of around half a million Israelis aged 60 or more commenced. The boosters were administrated during 10 days July 30 - Aug 8.

However, July 30 - Aug 26 there were a total of as many as 471 covid-19 deaths in Israel according to Worldometer, averaging 17 deaths per day.
The rate of deaths after infection increased more than 100% in this period compared to immediately before July 30.

Thus it seems possible to postulate that a cause of this rapid increase could be due to the mass vaccination of booster jabs. Almost all deaths in covid-19 occurs in the elderly, such as those aged 60+.

Now, regarding the article Protection of BNT162b2 Vaccine Booster against Covid-19 in Israel by Yinon M. Bar-On et al , the study did not take deaths into consideration at all in spite of the huge increase at that time in Israel.
However, for example, severe disease was followed up. There were only 9 such cases in the booster group compared to 294 in the control group. That sounds like a great result, but there is a serious problem here.

The follow up period started 12 days after the booster jab. Thus hundred+ people potentially might have died in the booster group before the follow up period started.
Of course none of them in that case would later qualify as with severe disease. They were already dead...

So the study protocol, specifically the chosen follow up starting time, could explain the extremely "good" result with only 9 severe covid-19 cases in the booster group. In reality one cannot rule out that there were a lot more deaths among the 60+ who received the booster jab.

Competing interests: No competing interests

21 September 2021
Bo A Engwall
Retired private analyst
Uppsala, Sweden