A new study by researchers from Washington University School of Medicine in St Louis has found that the Pfizer and Moderna Covid-19 vaccines can potentially induce long-lasting immunity.
Both mRNA vaccines are authorised in the US for emergency use and yielded positive data in clinical trials.
The latest data showed that people inoculated with the Pfizer vaccine had germinal centres in their lymph nodes about four months following the first dose.
Germinal centres form due to natural infection or vaccination and make immune cells directed against the SARS-CoV-2 virus. An improved germinal centre response is said to indicate a more effective vaccine.
In addition, the vaccine stimulated high neutralising antibodies levels, which were effective against three SARS-CoV-2 variants, including the Beta or South Africa variant that demonstrated some resistance to vaccines.
Individuals who recovered from Covid-19 experienced stronger antibody responses versus those who never contracted the infection, the researchers added.
In April 2021, both Pfizer and Moderna said that their vaccines offered protection for a minimum of six months. The companies based their reports on vaccinated people being infected.
Furthermore, certain groups tracked antibody levels in the blood and reported that the vaccine offers protection for at least months.
Washington University School of Medicine in St Louis pathology and immunology associate professor Ali Ellebedy said: “And the longer we have a germinal centre, the stronger and more durable our immunity will be because there’s a fierce selection process happening there, and only the best immune cells survive.
“We found that germinal centres were still going strong 15 weeks after the vaccine’s first dose. We’re still monitoring the germinal centres, and they’re not declining; in some people, they’re still ongoing. This is truly remarkable.”
For the study, the researchers obtained lymph node cells from 14 people who received the Pfizer vaccine.
All 14 participants formed germinal centres with B cells generating antibodies, which target an important SARS-CoV-2 protein, three weeks from the first dose.
The booster shot was observed to extend this response further.