An Imperial College London study released on Monday indicated that high numbers of T-cells from common cold coronaviruses have the ability to protect against Covid-19, which could inspire the development of techniques for the development of second-generation vaccines.
While there is evidence of diminishing antibody levels after six months of a double dose of vaccination, T-cells are also thought to play a key role in providing protection against the coronavirus that causes Covid-19.
The study, which began in September 2020, looked at levels of cross-reactive T-cells in 52 home contacts of positive Covid-19 patients early after being exposed to see if they developed an illness.
It was discovered that the 26 people who did not get infected had much larger levels of those T-cells compared to those who did get infected. The Imperial study did not specify how long the T-cells would provide such protection.
“We found that high levels of pre-existing T cells, created by the body when infected with other human coronaviruses like the common cold, can protect against COVID-19 infection,” study author Dr Rhia Kundu said.
The internal proteins of the SARS-CoV-2 virus, which are targeted by T-cells, could provide an alternative target for vaccine producers, according to the authors of the study, which was published in Nature Communications.
Current Covid-19 vaccines target the spike protein, which is prone to mutation, resulting in variants like Omicron. Such mutations reduce vaccine efficacy against symptomatic illness.
“In contrast, the internal proteins targeted by the protective T-cells we identified mutate much less,” Professor Ajit Lalvani, co-author of the study, said.
“Consequently, they are highly conserved between the various SARS-CoV-2 variants, including Omicron. New vaccines that include these conserved, internal proteins would therefore induce broadly protective T cell responses that should protect against current and future SARS-CoV-2 variants.”
(Adapted from NDTV.com)