Written By: Longjam Dineshwori | Updated : December 25, 2021 9:01 AM IST
fizer vaccine
Covid-19 vaccines created with mRNA vaccine technology are known to be highly effective at preventing at preventing coronavirus infection and severe disease. In clinical trials, the efficacy of Pfizer/BioNTech and Moderna mRNA COVID-19 vaccines at preventing symptomatic infection was found to be more than 90 per cent. Despite the emergence of the delta and omicron variants and, these vaccines remain quite effective at preventing hospitalizations and deaths. Wondering what makes mRNA vaccines so effective?
mRNA vaccines trigger exceptional antibody response by activating key helper immune cells known as T follicular helper cells, according to a new study published online in the journal Cell. The study was conducted by researchers at Washington University School of Medicine in St. Louis and St. Jude Children's Research Hospital.
As stated by the researchers, the Pfizer vaccine can strongly and persistently activate T follicular helper cells that assist antibody-producing cells in creating large amounts of increasingly powerful antibodies while also driving the development of some kinds of immune memory.
These helper cells last for up to six months after vaccination, and once they decline, long-lived antibody-producing cells and memory B cells help to provide protection against severe disease and death, the researchers explained.
Based on these findings, the researchers suggested that mRNA vaccines may help many recipients continue producing potent antibodies even as the virus changes.
"The longer the T follicular helper cells provide help, the better the antibodies are and the more likely you are to have a good memory response," said co-corresponding author Philip Mudd, MD, PhD, an assistant professor of emergency medicine at Washington University, as quoted by Science Daily.
They also found that some of T follicular helper cells are responding to one part of the virus's spike protein that has very little variation in it. This explains the efficacy of these mRNA vaccines in terms of preventing severe disease and death during delta and omicron infections.
While most vaccines contain a weakened or dead bacteria or virus, mRNA vaccine technology involves using a molecule called messenger RNA (or mRNA for short) that is necessary for protein production. Pfizer and Moderna vaccines work by work by introducing a piece of mRNA that directs cells to produce copies of a protein on the outside of the coronavirus known as the "spike protein". When the immune system recognizes that the protein is foreign, it produces specialized proteins called antibodies that help protect the body against infection. These antibodies remain in the body, even after the body after the bacteria or virus is destroyed, and this allows the immune system to quickly respond if exposed to the virus again.
Currently vaccines for COVID-19 are the only mRNA vaccines authorized or approved by the US Food and Drug Administration (FDA). Research is underway on to develop mRNA vaccines for additional infectious diseases.
