Researchers from Imperial College London (ICL) have revealed that T cells could provide more protection in COVID-19 vaccines against Omicron, a SARS-CoV-2 virus strain, than antibodies do.
The new review, published in Cell Host and Microbe, offers new insights into the development of COVID-19 vaccines and how T cells could play a crucial role in protecting people from these emerging variants.
Since being first identified in 2019, the SARS-CoV-2 virus has evolved with several variants and subvariants, such as Omicron, Pirola and Juno, leading to new waves of infection.
Although neutralising antibodies were considered to be the primary defence mechanism against COVID-19 during the pandemic, the virus has since evolved to become better at evading them.
The new research reveals that memory T cells, which play a key role in the body’s adaptive immune response to recurring viral infections, are more effective at recognising and combating the virus’ in comparison to antibodies.
This is especially true for people living with hybrid immunity obtained through vaccination and natural infection.
While further research is needed to understand the role of T cells in immunity to the virus’ different strains, researchers suggest that boosting T cell responses could provide stronger and longer-lasting protection against different strains of the virus.
Danny Altmann, co-author of the review and professor of immunology, ICL, said: “This recent work reminds us that… we’re still very much locked in a fast-moving arms-race against the virus.
“We need to be alert to keep reappraising strategies, making it important to understand these different immune mechanisms, including T cells.”
Last month, Novavax announced that its updated COVID-19 vaccine, Nuvaxovid XBB.1.5, had been approved by the Medicines and Healthcare products Regulatory Agency for the active immunisation of individuals aged 12 years and older.
The protein-based vaccine, which has been updated to include the spike proteins from the SARS-CoV-2 omicron variant lineage XBB.1.5, induced functional immune responses against the COVID-19 variants XBB.1.5, XBB.1.16 and XBB.2.3.
The vaccine also induced neutralising antibody responses to the newly emerging subvariants of the virus, JN.1, BA.2.86, EG.5.1, FL.1.5.1 and XBB.1.16.6, as well as strong CD4+ polyfunctional cellular (T-cell) responses against EG.5.1 and XBB.1.16.6.