INFECTION or VACCINATION driven SARS-CoV-2 T-cell response remains robust against OMICRON; great news for natural immunity HOLDING; despite > 30 mutations in the spike and 15 in the RBD

by Paul Alexander

OMICRON exhibits a significant capacity to evade the neutralizing antibody response; this reduces the vaccine's protection from infections

What does this pre-print say? Well we know that SARS-CoV-2 Omicron variant presently has 30 spike (S) protein mutations with a reported 15 alone on the receptor-binding domain (RBD). This leads to escape from the neutralizing antibody responses, and thus reduces vaccine protection from infection.

Researchers sought to examine the ability of immune T cells to react with Omicron spike in “participants who were vaccinated with Ad26.CoV2.S or BNT162b2, and in unvaccinated convalescent COVID-19 patients (n = 70).” Researchers reported that “70-80% of the CD4 and CD8 T cell response to spike was maintained across study groups. Moreover, the magnitude of Omicron cross-reactive T cells was similar to that of the Beta and Delta variants, despite Omicron harboring considerably more mutations. Additionally, in Omicron-infected hospitalized patients (n = 19), there were comparable T cell responses to ancestral spike, nucleocapsid and membrane proteins to those found in patients hospitalized in previous waves dominated by the ancestral, Beta or Delta variants (n = 49).”

These are very promising findings as they show that despite Omicron’s many mutations and reduced susceptibility to neutralizing antibodies, most of the T cell immune response driven by natural infection or vaccine, evidenced cross-recognition of the variant. The researchers also wrote “Well-preserved T cell immunity to Omicron is likely to contribute to protection from severe COVID-19, supporting early clinical observations from South Africa.”