What Are mRNA Vaccines? How Well Do They Work Against COVID-19?

Messenger RNA vaccines ¡ª also called mRNA vaccines ¡ª are a new type of vaccines to protect against the coronavirus.

To trigger an immune response, many vaccines put a weakened or inactivated germ into our bodies. Not mRNA vaccines. Instead, they teach our cells how to make a protein¡ªor even just a piece of a protein¡ªthat triggers an immune response inside our bodies, according to the CDC.

How are mRNA vaccines produced?

That immune response, which produces antibodies, is what protects us from getting infected if the real virus enters our bodies.

COVID-19 mRNA vaccines give instructions for our cells to make a harmless piece of what is called the ¡°spike protein.¡± The spike protein is found on the surface of the virus that causes COVID-19.

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Future mRNA vaccine technology may allow for one vaccine to provide protection for multiple diseases, thus decreasing the number of shots needed for protection against common vaccine-preventable diseases.

Currently, there are only a few mRNA vaccine developers - Pfizer, Moderna, CureVac and BioNTech.

Most mRNA know-how comes from cancer research

Most work on using mRNA to provoke an immune response has so far been focused on cancer, with tumour mRNA being used to help people¡¯s immune systems recognise and respond to the proteins produced by their specific tumours.

Because mRNA vaccines are only now beginning to be tested in humans, there are many things which are still unknown.

Lack of vaccine side effects no cause for concern

While a variety of side effects after receiving an mRNA COVID-19 vaccine may be a sign of the immune system kicking into high gear, a lack of such reactions does not mean it has failed to respond, researchers have found.

PTI

They tested 206 hospital employees for antibodies against the coronavirus before and after receipt of the vaccine from Pfizer and BioNTech and surveyed them about vaccine-related reactions.

As in clinical trials, arm pain was the most common symptom, reported by 91% after the first shot and 82 per cent after the second. Systemic symptoms, such as feeling weak or tired, or having body aches or pains, were reported by 42% and 28%, respectively, after the first shot and by 62% and 52% after the second shot.

mRNA vaccines limit severity of rare breakthrough infections

In the rare cases of COVID-19 that occur after vaccination, patients are likely to be sick for less time and have milder symptoms than if they were unvaccinated, according to a U.S. study of nearly 4,000 healthcare personnel, first responders, and other frontline workers.

In participants who were tested weekly since mid-December, COVID-19 has been diagnosed in five who were fully vaccinated with an mRNA vaccine from either Pfizer and BioNTech or Moderna, 11 who were partially protected, having received either one shot or were less than 14 days out from their second, and 156 who were unvaccinated.

Most unvaccinated patients were sick for at least two weeks, compared with only one week for vaccinated patients, the researchers reported on Wednesday in The New England Journal of Medicine.

Reuters

Patients who were fully or partially vaccinated had 58 per cent lower odds of fever and spent an average of 2.3 fewer days in bed than unvaccinated patients. Their viral loads also averaged 40 per cent lower.

"If you get vaccinated, about 90 per cent of the time you're not going to get COVID-19," coauthor Dr. Jeff Burgess of the University of Arizona said in a statement. "Even if you do get it, there will be less of the virus in you and your illness is likely to be much milder."