Pfizer-Biontech released a press release on the 31st of March announcing a 100 % efficacy rate on results in a Covid vaccine study on adolescents aged from 12 to 15. Several European news media reported on this. According to the study data, this claim is mostly true. However, Finnish experts say that to analyze the claim more closely more information would be needed than Pfizer-Biontech provides in the press release.
Pfizer-Biontech is a combination of two companies that have developed the Pfizer-Biontech vaccine. Pfizer is in charge of the research, while Biontech is in charge of manufacturing the vaccine. The study on adolescents has not yet been published or peer reviewed. Since the press release, Pfizer has received the US Food and Drug Administration (FDA) clearance for the vaccine.
A screenshot of Helsingin Sanomat newspaper reporting on the Pfizer-Biontech vaccine study on 12–15-year-olds.
What does the 100 % efficacy rate mean?
The Pfizer-Biontech vaccine has been approved in the USA and in the EU for people aged 16 and over. The companies did not take on developing a new vaccination but agreed to test their adult-approved vaccine on children.
In the study the vaccine was given to 1131 people without prior evidence of covid infection. None of the participants caught the Covid-19 virus. A placebo drug was given to a control group of 1129 people. Of the control group, 18 people got infected with Covid-19.
According to the Finnish Institute of Health and Welfare’s chief physician Dr. Hanna Nohynek, 100 % efficacy rate could mean several things: complete protection against either a) catching the virus, b) an illness that might lead to hospitalization or c) death. Therefore, it is important to specify what endpoints were used in measuring the efficacy – that is to say, what the goal of the study was.
Dr. Nohynek also pointed out that it is difficult to compare the outcomes of vaccine studies without sufficient data on the premises, population studied and epidemiological situations where the studies were carried out, as the study set ups vary.
Furthermore, Dr. Ilkka Seppä, physician coordinator of Tampere University’s Vaccine Research Center noted that fully developed vaccines rarely have an efficacy rate of 100 %.
On the media responsibility
It seems that the press release is aimed at investors and should be viewed from this particular perspective. The press release refers to Nasdaq information on the companies’ stock value and lists contact information of the companies’ investor relations staff, rather than their vaccine experts.
The press release was quoted in news around Europe immediately after its release. Noticeable was that many news medias did not provide a background on the topic.
It is true that the Pfizer-Biontech vaccine offers a protection against Covid-19 for 12–15-year-olds in this stage of development, but the claim of 100 % effectiveness is relative. According to the chief physician of the Finnish Institute of Health and Welfare, Dr. Hanna Nohynek, we need specific information on the goals of each study to be able to evaluate the study results.
RESEARCH | ARTICLE © Viivi Koski, Heli Laakkonen, Elli Maaranen. Haaga-Helia University of Applied Sciences, FI