Covid infection before vaccination lowers immunity: Study

Author: APP

If you had Covid infection before you took vaccination, chances are that you might have less immunity, claimed a study.

Researchers at the Stanford University in the US found that the magnitude and quality of a key immune cell’s response to vaccination with two doses of the Pfizer-BioNTech Covid-19 vaccine were considerably lower in people with prior SARS-CoV-2 infection compared to people without prior infection.

In addition, the level of this key immune cell that targets the SARS-CoV-2 spike protein was substantially lower in unvaccinated people with Covid-19 than in vaccinated people who had never been infected.

Importantly, people who recover from SARS-CoV-2 infection and then get vaccinated are more protected than people who are unvaccinated, Medical Xpress reported .

These findings, which suggest that the virus damages an important immune-cell response, were published in the journal Immunity.

Led by Mark M. Davis, Professor of microbiology and immunology at Stanford’s School of Medicine, the researchers designed a very sensitive tool to analyse how immune cells called CD4+ T cells and CD8+ T cells respond to SARS-CoV-2 infection and vaccination.

These cells coordinate the immune system’s response to the virus and kill other cells that have been infected, helping prevent Covid.

The tool was designed to identify T cells that target any of dozens of specific regions on the virus’s spike protein as well as some other viral regions. The Pfizer-BioNTech vaccine uses parts of the SARS-CoV-2 spike protein to elicit an immune response without causing infection.

The investigators studied CD4+ and CD8+ T-cell responses in blood samples from three groups of volunteers. One group had never been infected with SARS-CoV-2 and received two doses of the Pfizer-BioNTech Covid-19 vaccine. The second group had previously been infected with SARS-CoV-2 and received two doses of the vaccine. The third group had Covid-19 and was unvaccinated.

The researchers found that vaccination of people who had never been infected with SARS-CoV-2 induced robust CD4+ and CD8+ T-cell responses to the virus’ spike protein. In addition, these T cells produced multiple types of cell-signalling molecules called cytokines, which recruit other immune cells — including antibody-producing B cells — to fight pathogens.A

However, people who had been infected with SARS-CoV-2 prior to vaccination produced spike-specific CD8+ T cells at considerably lower levels — and with less functionality — than vaccinated people who had never been infected.

Moreover, the researchers observed substantially lower levels of spike-specific CD8+ T cells in unvaccinated people with Covid than in vaccinated people who had never been infected.

Overall, these findings suggest that SARS-CoV-2 infection damages the CD8+ T cell response, an effect akin to that observed in earlier studies showing long-term damage to the immune system 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.

Share
Leave a Comment

Recent Posts

  • Pakistan

France announces aid to back global fight against polio in Pakistan

French Ambassador to Pakistan, Nicolas Galey, has reaffirmed France's support for Pakistan's polio eradication efforts,…

37 mins ago
  • Pakistan

Punjab CM briefs NDU delegation on Punjab development initiatives

Punjab Chief Minister Maryam Nawaz Sharif Thursday met the participants in the 26th National Security…

38 mins ago
  • Pakistan

ATC approves Imran’s physical remand in vandalism case

An anti-terrorism court has approved a five-day physical remand of former PTI chairman Imran Khan,…

38 mins ago
  • Pakistan

Qureshi, others indicted in May 9 case

An anti-terrorism court (ATC) on Thursday indicted several Pakistan Tehreek-e-Insaf (PTI) leaders, including Shah Mehmood…

39 mins ago
  • Pakistan

Pakistan voices regret after US veto on Gaza ceasefire bid

Pakistan expressed its "deep regret" over the United States' veto of a UN Security Council…

39 mins ago
  • Pakistan

PM calls for third party validation of govt procurements

Prime Minister Shehbaz Sharif on Thursday directed the relevant authorities to ensure third party validation…

40 mins ago