COVID vaccines provide robust protection against Omicron-driven severe disease, hospitalisation

February 2, 2022

A new research has claimed that existing COVID-19 vaccines provide robust safety against severe disease and hospitalization caused by both the Delta and Omicron variants of the pandemic.
The study, published in the journal Nature on Monday, showed that the vaccines induce protection through cellular immunity or the production of protective immune cells, such as so-called killer and memory cells.
“Our data provide immunological context for the observation that current vaccines still provide robust protection against severe disease and hospitalisation due to the Omicron variant despite substantially reduced neutralising antibody responses and increased breakthrough infection,” said corresponding author Dan H Barouch.
The study was conducted by a team of researchers at Beth Israel Deaconess Medical Center (BIDMC) in Israel using the samples of 47 uninfected individuals who received either the Johnson & Johnson or Pfizer-BioNTech vaccines.
Cellular immunity continues to protect from severe COVID-19 disease despite the Omicron variant’s evasion of neutralising antibodies, the researchers said.
They measured CD8+ T cell and CD4+ T cell responses to the original, Delta and Omicron strains of the SARS-CoV-2 virus after one month and then again after eight months following final vaccination.
Both CD4 and CD8 cells, also known as T cells, are white blood cells that fight infection and play an important role in the immune system, PTI reported.

“Given the role of CD8+ T cells in clearance of viral infections, it is likely that cellular immunity contributes substantially to vaccine protection against severe SARS-CoV-2 disease,” said Barouch, whose team was involved in the development of Johnson and Johnson vaccine.
“This may be particularly relevant for Omicron which dramatically evades neutralising antibody responses,” he said