Early concerns raised over levels of intact mRNA in Pfizer vaccine


RECENT studies confirm that mRNA vaccines are safe and provide a high degree of protection against Covid-19.

However, leaked emails show that there were doubts last year about early commercial batches of the Pfizer-BioNTech mRNA vaccine.

The emails reveal that the European Medicines Agency (EMA) raised concerns with Pfizer that the vaccine contained 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 growing evidence that vaccination programs are already protecting some of the most vulnerable individuals from Covid-19, reducing the number of severe infections and preventing deaths.

While clinical trials in 2020 found mRNA vaccines to be safe and effective, several recent studies suggest that they also provide a high degree of protection in the “real world.”

For instance, a study by researchers in the United Kingdom, one that has not yet been peer-reviewed, found that a single dose of the Pfizer-BioNTech vaccine is up to 79.3% effective at reducing the risk of hospital admission with Covid-19 in adults over 80 years of age.

Stay informed with live updates on the current Covid-19 outbreak and visit our coronavirus hub for more advice on prevention and treatment.

Another study in the U.K. estimates the vaccine’s effectiveness at 89% from 14 days after the second shot. This research has also not undergone peer review yet.

In the U.S., a 2021 study, which has not yet been peer-reviewed, found that two doses of either the Pfizer vaccine or another mRNA vaccine made by Moderna was 88.7% effective at preventing a SARS-CoV-2 infection in adults.

It therefore comes as a surprise to learn that in November 2020, the EMA raised concerns that proposed commercial batches of the Pfizer vaccine did not contain as many intact mRNA molecules as expected.

Each mRNA molecule in a vaccine is a genetic template that provides instructions for making a single viral protein.

When human cells take up the mRNA, they use it to manufacture millions of copies of the protein.