Immune cells against COVID-19 remain active for six months after vaccination

Findings of the study, published in the journal Clinical Infectious Diseases, showed that helper T cells persisted for more than six months after vaccination, with only slightly lower levels from two weeks after vaccination and compared with those who did not. very high levels that are not vaccinated.

According to the US Centers for Disease Control and Prevention, the delta variant—currently the dominant strain of SARS-CoV-2 worldwide—causes more infections and spreads faster than earlier forms of the virus. “Previous research has suggested that the humoral immune response – where the immune system transmits virus neutralizing antibodies – may kick off six months after vaccination, whereas our study indicates that cellular immunity – where the immune system directly attacking the infected cells – stays strong,” said senior author Joel Blankenson, professor of medicine at the Johns Hopkins University School of Medicine, adding that “the persistence of these vaccine-elicited T cells, along with the fact that they are not the delta variant.” are active against, have important implications for guiding COVID. -19 vaccine development and determining the need for future COVID-19 boosters,” Blankenson said.

To reach these findings, Blankenson and colleagues obtained blood from 15 study participants (10 men and five women) three times: before vaccination, between seven and 14 days after their second Pfizer/BioNTech or Moderna vaccine dose, and six months after vaccination. Participants had a mean age of 41 years and none had evidence of prior SARS-CoV-2 infection.

CD4+ T lymphocytes called helper T cells help another type of immune system cell, the B lymphocyte (B cell), respond to surface protein-antigen-on viruses such as SARS-CoV-2. Activated by CD4+ T cells, immature B cells become either plasma cells that produce antibodies to mark infected cells for disposal from the body or memory cells for rapid responses to future infections. “remembers” the biochemical structure of the antigen.

Therefore, a CD4+ T cell response can serve as a measure of how well the immune system responds to a vaccine and produces humoral immunity.

The researchers also looked at the ability of CD4+ T cells to recognize the spike protein above the SARS-CoV-2 delta variant six months after vaccination. They found that the number of T cells that recognized the delta variant spike protein was not significantly different from that of T cells bound to the protein of the original virus strain.

“Strong expansion of T cells in response to stimulation with spike proteins is definitely indicated, supporting the need for more studies to show booster shots increase the frequency of SARS-CoV-2-specific T cells circulating in the blood.” successfully increases,” said Blankenson. “The added bonus is finding that this response is likely to be stronger for the delta version as well.”

The World Health Organization (WHO) said in its latest weekly epidemiological update that the delta variant of the SARS COV2 virus has overtaken other forms, including other forms of concern, in most countries. The United Nations health agency said the delta variant has shown prominence globally, with the prevalence of other variants declining among publicly available datasets or sequences reported to the WHO.

The delta version of the SARS-CoV-2 virus, which was first detected in India, is now present in more than 104 countries. The WHO warned earlier in July that the variant was expected to be the dominant COVID-19 strain to spread worldwide.

In June, the WHO warned that the delta variant was the most transmissible of all the variants identified so far and was spreading rapidly among unvaccinated populations. The types of concerns detected in community samples in India are alpha (3,969), beta (149) and gamma (1).

Vaccines from Pfizer and Moderna will soon be in the bouquet of Kovid-19 vaccines in India.

“The number of fully vaccinated persons has crossed the partially vaccinated population for the first time in the country. With the administration of 6,782,042 vaccine doses in the last 24 hours, Union Minister of Health and Family Welfare Mansukh Mandaviya said As per the provisional report at 7 am today, more than 113.68 crore (1,136,879,685) have been administered and every Indian has been vaccinated by the end of the month-long ‘Har Ghar Dastak’ campaign.

The month-long ‘Har Ghar Dastak’ vaccination campaign aims to ensure that all adult population is covered with the first dose of the COVID vaccine, while those taking the second dose are encouraged to take the second dose. Healthcare workers are conducting door-to-door immunization of eligible people across India, with a special focus on districts where less than 50% of the eligible population has been vaccinated. India’s cumulative COVID-19 immunizations touched close to 114 crores on Wednesday. India recorded over 10,197 coronavirus cases in the last 24 hours.