In research conducted by scientists from the Washington University School of Medicine in the United States, it was found that the two vaccines created a constant immune reaction to the virus in the body that protects itself against COVID-19, online medical news agency Health reported on Tuesday.
The research indicated that booster shots might not be needed to protect against the existing variants, unless new strains emerge and are stronger than the two messenger RNA-based vaccines.
The researchers looked at the cells in the lymph nodes of the individuals who were vaccinated and took part in the study. They determined that the cells were consistently practicing how to defend the body against the virus after the first shot was given to them.
A specialized structure referred to as the germinal center forms in the lymph nodes after an infection or vaccination. This means that the more these cells practice creating an adequate immune response, the more likely they will be able to protect the individual against variants of the virus, should they emerge.
According to the immunologist Dr. Ellebedy and his team, the germinal center was still highly active in all fourteen of the study’s participants 15 weeks after receiving the first dose of the vaccine, adding that the number of memory cells that recognized the virus did not decline.
“It’s a good sign for how durable our immunity is from this vaccine,” Dr. Ali Ellebedy who is based at the Washington University in St. Louis told the New York Times. “The fact that the reactions continued for almost four months after vaccination – that’s a very, very good sign.”
Dr. Ellebedy added that the study did not consider the Janssen COVID-19 jab by Johnson and Johnson, but said that he expected the immune response to the virus to be less durable than mRNA vaccines.
The researchers of the study, including Dr. Ellebedy, reported that the immune cells that recognized the virus in individuals who had previously fought off COVID-19 remained in the bone marrow for at least eight months after the infection. This suggested that immunity might last years in people who were previously infected and later vaccinated, The New York Times reported.
The results of the study suggested that a vast majority of people who are vaccinated with Pfizer or Moderna would be protected in the long run against existing variants. However, older adults or people with weaker immune systems will need booster shots.
The exact length of the protection provided by mRNA vaccines against the virus has not been determined.