- Recent studies confirm that mRNA vaccines are safe and offer a high degree of protection against COVID-19.
- However, leaked emails show that there was doubt last year about early commercial groups of the Pfizer-BioNTech mRNA vaccine.
- The emails show that the European Medicines Agency (EMA) has expressed concern about Pfizer’s that the vaccine contains lower levels of intact mRNA molecules than expected.
- The company resolved the issue to the satisfaction of the EMA and regulatory agencies in the United States and Canada.
There is increasing evidence that vaccination programs already protect some of the most vulnerable individuals against COVID-19, reduce the number of serious infections and prevent deaths.
While clinical trials in 2020 found that mRNA vaccines are safe and effective, several recent studies indicate that they also offer a high degree of protection in the ‘real world’.
In a study by researchers in the UK, one that has not yet been peer-reviewed, a single dose of Pfizer-BioNTech vaccine was found to be up to 79.3% effective in reducing the risk of hospitalization with COVID -19 to reduce. in adults older than 80 years.
Another study in the UK estimates the efficacy of the vaccine at 89% from 14 days after the second ingestion. This research has also not yet undergone a peer review.
In the US, a 2021 study, not yet peer-reviewed, found that two doses of the Pfizer vaccine or another mRNA vaccine made by Moderna were 88.7% effective at a Prevent SARS-CoV-2 infection in adults.
It is therefore surprising to hear that the EMA in November 2020 expressed concern that proposed commercial groups of the Pfizer vaccine do not contain as many intact mRNA molecules as expected.
Each mRNA molecule in a vaccine is a genetic pattern that gives instructions to make a single viral protein.
When human cells take up the mRNA, it uses millions of copies of the protein. These are harmless fragments of the virus, but they elicit an immune response that protects a person from future infection throughout the virus.
However, RNA molecules break down easily, so mRNA must be stored at very low temperatures. To further stabilize the mRNA in vaccines, manufacturers encapsulate the molecules in small fat spots called lipid nanoparticles.
‘[T]a complete, intact mRNA molecule is essential for its potential as a vaccine, ‘writes Daan JA Crommelin, professor of biopharmaceuticals at Utrecht University in the Netherlands, and his colleagues in the Journal of Pharmaceutical Sciences in December 2020.
They noted that even slight deterioration anywhere along the length of the mRNA strand can slow down or prevent the cell from making the virus protein proper.
Internal emails show that in November 2020, the EMA was concerned that groups of the Pfizer vaccine proposed for commercial use contained less intact mRNA than previous groups made for clinical trials.
Only about 55% of the mRNA molecules in those early commercial groups remained intact.
The doubts that the EMA first came to light as a result of a cyber attack on the agency’s computer system in December 2020.
Unknown persons sent the leaked e-mail to several journalists, including at The BMJ, and the magazine has now published an investigation into the agency’s concerns.
Pfizer has apparently addressed all the questions raised by the EMA, which approved the vaccine on 21 December 2020.
According to one of the leaked emails, dated November 25, 2020, an unknown source in the US gave the agency positive news: ‘The latest lots indicate that% intact RNA is around 70-75%, which leaves us cautiously optimistic that additional data may address the issue. ”
The BMJ reports that the EMA, the Food and Drug Administration (FDA) and Health Canada worked together during the approval process and applied common criteria.
Health Canada tells The BMJ that Pfizer investigated the “cause” of the problem with the commercial groups.
‘[C]”hangs were made in their processes to ensure that the integrity improved and matched what was seen for groups for clinical trials,” the EMA said.
Health Canada further revealed that all three medical agencies subsequently concluded that “there was no concern about RNA integrity or any other product specifications.”
While regulators have confidence in the safety and efficacy of all the mRNA vaccines currently in use, questions remain as to what criteria they use during the approval process for this relatively new technology.
When The BMJ approached producers and several national regulators for comment, no one disclosed what percentage of intact mRNA molecules they consider acceptable.
The FDA, the EMA and Health Canada have all told the magazine that specific details about the eligibility criteria are confidential.
The EMA stressed that the amounts of protein that a truncated mRNA strand could potentially produce would be “too low to pose a safety risk.”
The agency also stressed that Pfizer had addressed their concerns about the amount of intact mRNA in the vaccine.
The article notes: “Each group of vaccines is tested by the official laboratory for medicinal control – the [Paul-Ehrlich-Institut] in Germany – before the release of the final product. As a result, the quality of all vaccine doses placed on the market in Europe has been doubly tested to ensure compliance with the specifications agreed by the regulatory authorities. ”
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