Pfizer, Moderna covid vaccine boosts immunity of previously infected people

The study was published Wednesday in the scientific journal eLife and was conducted by the Gladstone Institutes. “Overall, our data support the idea that vaccines elicit a very strong T cell response in healthy individuals, but they also elicit vaccine-induced T cells. It suggests that there may be some ways to improve them by parking them in the airways, “said Nadia Lone, senior author of the study.

Scientists have explained that the human immune system has two major weapons that can help fight recurrent infections. Antibodies produced by the B cells of the immune system can quickly recognize the virus, target it for destruction, and prevent infection. T cells, on the other hand, identify and destroy already infected cells. Antibodies are more effective at stopping the initial infection altogether, but T cells generally last longer after the initial infection or vaccination, helping to calm the disease in the early stages and prevent serious symptoms. However, scientists said T cells are diverse and difficult to study.

“It’s not just the number of T cells that matters, it’s the quality. Whether the T cells are the type that can actively destroy virus-infected cells,” said CyTOF, an associate professor of urology at the University of California, San Francisco. Roan says he can measure the levels of nearly 40 different proteins using a technique called. The surface and interior of T cells. The technique under study has accurately identified which subset of T cells were able to recognize SARS-CoV-2 before and after vaccination.

The researchers used this approach to study blood samples from 11 people who received the mRNA vaccine against SARS-CoV-2 (Pfizer / BioNTech or Moderna). Blood samples were collected from each individual before vaccination, about 2 weeks after the first vaccination, and about 2 weeks after the second vaccination. Six of the individuals had previously recovered from mild covid-19.

Scientists have found that all fully vaccinated individuals in this study have T cells that respond to three different variants of SARS-CoV-2. The first B.1.17 variant detected in the United Kingdom. The first B.1.351 variant detected in South Africa. The delta variant of the virus was not included in the treatise, but scientists are currently analyzing data about it.

In people who have never been infected with SARS-CoV-2, researchers have found that the T cell response is stronger in both quantity and quality after the second vaccination. However, in people who had previously been infected with covid-19, there was little change between the first and second doses of the vaccine.

“This does not necessarily mean that convalescent individuals do not benefit from the second dose. This does mean that there are no additional effects that can be captured by T cells, but the second dose. After administration, there may be other effects on the immune system, such as in B cells, “Roan said.

Researchers also found that while all individuals showed a strong T-cell response, immune cells persisted longer and migrated more effectively into the airways to T cells in previously infected individuals. We also discovered that there are molecular markers that suggest what we can do.

Potentially more effective T cell protection in the respiratory tract may explain why breakthrough infections are lower in previously covid-19-infected individuals compared to other vaccinated individuals. New data also suggest that improving the ability of T cells to move into the respiratory tract after vaccination may improve the effectiveness of the vaccine in preventing breakthrough infections, Roan said. ..