The high T-cell levels of the common cold may provide protection against Covid-19, a study by Imperial College London found Monday could provide information for the development of second-generation vaccines.
Immunity against Covid-19 is a complex picture, and while there is evidence of a drop in antibody levels six months after vaccination, T cells are thought to also play a vital role in providing protection.
The authors of the article present the first evidence that T cells induced by other coronaviruses can recognize SARS-CoV-2 and build protection against it.
The study, which began in September 2020, looked at the levels of cross-reactive T cells generated by previous colds in 52 household contacts with positive cases of Covid-19 shortly after infection to see if they develop an infection.
It was found that 26 people who did not develop the infection had significantly higher levels of these T cells than those who did. Imperial College did not say how long T-cell protection lasts.
“We found that high levels of pre-existing T cells created by the body when infected with other human coronaviruses, such as the common cold, can protect against Covid-19 infection,” said study author Dr. Ria Kundu.
The authors of the study, published in Nature Communications, said the internal proteins of the SARS-CoV-2 virus, which T cells target, could be an alternative target for vaccine manufacturers.
Current Covid-19 vaccines target a spike protein that mutates regularly, creating variants like Omicron that reduce the effectiveness of vaccines against symptomatic infection.
“In contrast, the intrinsic proteins that are targeted by the protective T cells that we have identified mutate much less,” said Professor Ajit Lalwani, co-author of the study.
“Hence they are very conservative between the various SARS-CoV-2 variants, including Omicron. Thus, new vaccines that include these conserved internal proteins will induce a broad protective T-cell response that should protect against current and future SARS-CoV-2 variants. ”