Enlarge image
Booster vaccination in Modi'in, Israel
Photo: Gil Cohen Magen / Xinhua / IMAGO
In Germany, the Standing Vaccination Commission (Stiko) recommends a booster vaccination against Covid-19 for all people aged 70 and over and some risk groups if the basic immunization was at least six months ago.
The Federal Ministry of Health emphasizes: In principle, everyone in Germany is entitled to this booster, even if it is currently not recommended by Stiko for everyone.
A research team used data from Israel to investigate what additional protection a third vaccination with the means from Biontech and Pfizer offers.
Booster vaccinations are now planned in the country for everyone from the age of twelve whose second Biontech vaccination was at least five months ago.
Comparison of double and triple vaccinations
To determine the effectiveness of the third vaccination, the team compared around 728,000 three-times vaccinated with the same number of double-vaccinated people who had not yet decided on a third vaccination. The groups were chosen in such a way that they were similar in terms of the risk factors for a severe course of Covid-19, i.e. with regard to age, previous illnesses, gender. On average, the participants were 52 years old. The effectiveness of the booster vaccination was therefore not determined in comparison to no vaccination at all, but in comparison to the basic vaccination with two doses of Pfizer / Biontech.
As they report in the journal "The Lancet", the researchers were primarily concerned with the number of severe Covid-19 courses, hospital admissions and Covid-19-related deaths.
These are more important for public health than mild or asymptomatic corona infections, writes the Noam Barda and Noa Dagan group from the Clalit Research Institute in Tel Aviv.
The subjects were observed from the seventh day after the third vaccination for an average of almost two weeks - with the following results:
In the group with a third vaccination, 29 people had to be
hospitalized
for Covid-19
, in the group with double vaccinations there were 231. This corresponds to an
effectiveness of 93 percent
the third vaccination versus the double vaccination. (The effectiveness is calculated as follows: The cases in the less protected group, in this case only double vaccinated, correspond to 100 percent. Now you look at the percentage of the cases in the better protected group. If you subtract this percentage from 100 If you are now wondering that 29 corresponds to 13 percent of 231, and the effectiveness should be 87 percent and not 93. The calculation in the study is a little more complex, it follows the so-called Kaplan-Meier estimator, a detailed description can be found in the specialist article.)
Of the three times vaccinated, 17 had a
severe course of Covid-19
, of the double-vaccinated 157 were affected.
This corresponds to an
effectiveness of 92 percent
.
Seven people who were triple vaccinated died in connection with Covid-19, and there were 44 such
deaths
among those who were double vaccinated
.
This corresponds to an
effectiveness of 81 percent
.
The effectiveness of the third dose against a severe course and hospitalization was similar in men and women, and in people over 40 years of age, the effectiveness did not change with age.
In the group of under 40-year-olds, the number of severe courses was so low that the effectiveness of the booster vaccination could not be assessed, according to the study.
Booster vaccinations can further delay global vaccine distribution
In an accompanying commentary in The Lancet, K. Srinath Reddy of the Indian Public Health Foundation wrote that the Israeli study only relates to the vaccine from Pfizer and Biontech. Accordingly, it says nothing about how a third vaccination affects other vaccines. He also points out that the benefits and risks of third-party vaccination must be weighed up in different age groups. During the second vaccination with mRNA vaccines like the one from Biontech, myocarditis occurred in rare cases, especially in younger men. Now you are waiting for the safety data of the third vaccinations, so Reddy. The study does not report possible complications from the vaccination.
The authors of the study do not want to answer another important question: namely, whether it makes sense or is fair to give people a third vaccination while in many countries a great many people are still waiting for their first vaccination. "It is beyond the scope of this epidemiological analysis to address the complex ethical issues involved in this debate, but there is an urgent need for increased production, distribution and access to vaccines worldwide," the paper simply states.
Reddy expresses his point of view in the comment: The injustice in the distribution of the vaccines is a global problem, he writes.
If it is accepted that the nations with a lot of vaccines offer a booster vaccination to all citizens from the age of twelve, this could increase the vaccine shortage in other countries.
“In this scenario, insufficiently vaccinated groups could create the conditions for new virus variants that are not only more infectious but also have greater immune escape, and these variants could invade countries with high vaccination protection and trigger new waves of infection.
It's not the kind of natural experiment the world would like to see. ”Countries that protect their own populations also need to ensure vaccine supplies in other countries.
The World Health Organization (WHO) had set a goal that at least ten percent of the population in every country should be vaccinated by the end of September.
56 countries that were "effectively excluded from the global vaccine trade" could not have achieved this goal, writes the organization.
African countries are particularly affected.
Even more countries would miss the next target of vaccinating 40 percent of the population by the end of the year.
