by A recent investigation by The BMJ has sparked a debate over whether Pfizer should have disclosed important safety information to pregnant women participating in its maternal respiratory syncytial virus (RSV) vaccine trial. The investigation revealed that Pfizer’s vaccine, known as Abrysvo, was granted approval for use in the US and the European Union, but has not yet been authorized in the UK.
The controversy stems from the fact that a trial of a similar RSV vaccine developed by GSK was halted due to a safety signal related to preterm birth. Some experts argue that Pfizer should have informed participants of this potential risk, while others believe that such notification would have been premature and caused undue anxiety.
RSV is a respiratory virus that typically causes mild symptoms resembling a common cold in most people, but can be severe and even fatal in young children. Both GSK and Pfizer were working on recombinant RSV F protein vaccines aimed at vaccinating pregnant women to protect their babies.
In February 2022, GSK halted its phase 3 trial after a possible increase in preterm births was observed. Although the cause is still being investigated and experts speculate that it may be unrelated to the vaccine, GSK has decided not to continue developing its vaccine. In Pfizer’s own phase 3 trial, preterm births were also being studied as an adverse event of interest, and although a numerical imbalance in preterm births has been observed, there is currently insufficient data to determine if there is a true increased risk or determine the cause.
Following the halt of GSK’s trial, opinions were divided among clinical trial ethicists and vaccine researchers regarding whether Pfizer should have informed all participants in its trial about the potential risk or updated the consent forms. Charles Weijer, a bioethics professor at Western University, argued that informing pregnant women in Pfizer’s trial about the results of GSK’s trial would have allowed them to make informed decisions about receiving the vaccine or seeking additional medical advice. Failure to provide new and potentially important safety information to trial participants is ethically problematic, according to Weijer.
Pfizer has faced further criticism for including a passage in some of its trial consent forms that declared its vaccine candidate to be risk-free for babies. This assertion was described as misleading and irresponsible by a research ethics expert.
Regulators have taken different approaches in approving Abrysvo. For example, the US Food and Drug Administration (FDA) approved the vaccine with conditions, including limiting administration to women who are 32-36 weeks pregnant and including a warning about a numerical imbalance in preterm births in the prescribing information. The FDA is also requiring Pfizer to conduct postmarketing studies to assess the potential risk of preterm birth. On the other hand, the European Medicines Agency (EMA) and the UK’s Joint Committee on Vaccination and Immunisation (JCVI) did not believe it necessary to issue warnings or restrict the use of the vaccine to later stages of pregnancy.
When asked about whether Pfizer had informed expectant mothers in its trial about the results of GSK’s trial, the company did not respond. The BMJ extensively reached out to governmental health authorities in the 18 countries where Pfizer conducted its trial, as well as over 80 trial investigators, but none reported receiving such information.
Despite the news of the potential risk of preterm birth in GSK’s vaccine trial becoming public, Pfizer continued to enroll and vaccinate women for months, as confirmed by some trial investigators. One investigator, who chose to remain anonymous due to a confidentiality agreement, stated that they had raised concerns early in 2022 about the potential risk of preterm birth given the similarities between Pfizer and GSK’s products, but were assured by Pfizer that their data did not show an increased risk.
While some trial investigators disagreed with the idea of informing participants, citing the irrelevance of GSK’s results for their trial, others highlighted contradictory statements in Pfizer’s trial consent forms. These contradictions included warnings of potential life-threatening effects on the baby while also stating that only the expectant mother was at risk of adverse effects. Such discrepancies have been described as irresponsible and factually incorrect by research ethics experts.
The controversial statement in the consent forms raises concerns about the validity of the consent process, especially considering the seriousness of the risk it obscures.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
Money Singh is a seasoned content writer with over four years of experience in the market research sector. Her expertise spans various industries, including food and beverages, biotechnology, chemical and materials, defense and aerospace, consumer goods, etc.
