According to one study, if you had Covid infection before receiving immunisation, you may have decreased immunity.
The magnitude and quality of a key immune cell’s response to vaccination with two doses of the Pfizer-BioNTech Covid-19 vaccine were significantly lower in people with prior SARS-CoV-2 infection compared to people without prior infection, according to researchers at Stanford University in the United States.
Also, the level of this critical immune cell that targets the SARS-CoV-2 spike protein in unvaccinated people with Covid-19 was significantly lower than in vaccinated people who had never been infected.
Significantly, those who recover from SARS-CoV-2 infection and then become vaccinated are more protected than uninfected people.
These findings, which imply that the virus interferes with a critical immune-cell response, were published in the journal Immunity.
The researchers, led by Mark M. Davis, Professor of Microbiology and Immunology at Stanford University School of Medicine, developed a highly sensitive technique to examine how immune cells known as CD4+ T cells and CD8+ T cells respond to SARS-CoV-2 infection and vaccination.
These cells help to prevent Covid by coordinating the immune system’s reaction to the virus and killing infected cells.
The method was created to detect T cells that target any of dozens of distinct sites on the virus’s spike protein, as well as several other viral areas. Parts of the SARS-CoV-2 spike protein are used in the Pfizer-BioNTech vaccine to stimulate an immune response without generating illness.
The researchers looked at CD4+ and CD8+ T-cell responses in blood samples from three different groups of volunteers. One group had never had SARS-CoV-2 infection and got two doses of the Pfizer-BioNTech Covid-19 vaccine. The second group had been infected with SARS-CoV-2 earlier and got two doses of the vaccination. The third group had Covid-19 and had not been immunised.
The vaccine produced significant CD4+ and CD8+ T-cell responses to the virus’ spike protein in patients who had never been infected with SARS-CoV-2, according to the researchers. Furthermore, these T cells released a variety of cell-signaling molecules known as cytokines, which attract other immune cells, including antibody-producing B cells, to combat infections. A
Those who had been infected with SARS-CoV-2 before to vaccination, on the other hand, developed much less spike-specific CD8+ T cells – and with less functionality – than vaccinated people who had never been infected.
Also, unvaccinated patients with Covid had much lower amounts of spike-specific CD8+ T cells than vaccinated people who had never been infected.
Overall, our data suggest that SARS-CoV-2 infection affects the CD8+ T cell response, a finding that is consistent with previous research indicating long-term immune system harm after infection with viruses such as hepatitis C or HIV.
“The new findings highlight the need to develop vaccination strategies to specifically boost antiviral CD8+ T cell responses in people previously infected with SARS-CoV-2,” the researchers said.
