EPISODE · Jul 1, 2026 · 17 MIN
Omicron science, promising news
from Dr. John Campbell · host Campbellteaching
New science explains South Africa's low rates of omicron severe disease SARS-CoV-2 spike T cell responses induced upon vaccination or infection remain robust against Omicron https://www.medrxiv.org/content/10.1101/2021.12.26.21268380v1 https://www.medrxiv.org/content/10.1101/2021.12.27.21268278v1 Institute of Infectious Disease and Molecular Medicine, University of Cape Town SARS-CoV-2 Omicron variant has multiple Spike (S) protein mutations These contribute to escape from the neutralizing antibody responses, reducing vaccine protection from infection We assessed the ability of T cells to react with Omicron spike In participants who were vaccinated with Ad26.CoV2.S (J and J) (n = 20) or BNT162b2 (Pfizer) (n = 15 or in unvaccinated convalescent COVID-19 patients (n = 15) SARS-CoV-2-specific T cells play a key role in modulating COVID-19 severity and provide protective immunity Results 70-80% of the CD4 and CD8 T cell response to spike was maintained across study groups The magnitude of Omicron cross-reactive T cells was similar to that of the Beta and Delta variants These results demonstrate that, despite Omicron’s extensive mutations and reduced susceptibility to neutralizing antibodies, the majority of T cell response, induced by vaccination or natural infection, cross- recognises the variant. Well-preserved T cell immunity to Omicron, is likely to contribute to protection from severe COVID-19, supporting early clinical observations from South Africa. Further explanation The limited effect of Omicron’s mutations on the T cell response suggests that vaccination or prior infection may still provide substantial protection from severe disease. Indeed, South Africa has reported a lower risk of hospitalisation and severe disease compared to the previous Delta wave Cross-reactive T cell responses acquired through vaccination or infection may contribute to these apparent milder outcomes for Omicron. The resilience of the T cell response demonstrated here also bodes well in the event that more highly mutated variants emerge in the future. Learn more about your ad choices. Visit megaphone.fm/adchoices
What this episode covers
New science explains South Africa's low rates of omicron severe disease SARS-CoV-2 spike T cell responses induced upon vaccination or infection remain robust against Omicron https://www.medrxiv.org/content/10.1101/2021.12.26.21268380v1 https://www.medrxiv.org/content/10.1101/2021.12.27.21268278v1 Institute of Infectious Disease and Molecular Medicine, University of Cape Town SARS-CoV-2 Omicron variant has multiple Spike (S) protein mutations These contribute to escape from the neutralizing antibody responses, reducing vaccine protection from infection We assessed the ability of T cells to react with Omicron spike In participants who were vaccinated with Ad26.CoV2.S (J and J) (n = 20) or BNT162b2 (Pfizer) (n = 15 or in unvaccinated convalescent COVID-19 patients (n = 15) SARS-CoV-2-specific T cells play a key role in modulating COVID-19 severity and provide protective immunity Results 70-80% of the CD4 and CD8 T cell response to spike was maintained across study groups The magnitude of Omicron cross-reactive T cells was similar to that of the Beta and Delta variants These results demonstrate that, despite Omicron’s extensive mutations and reduced susceptibility to neutralizing antibodies, the majority of T cell response, induced by vaccination or natural infection, cross- recognises the variant. Well-preserved T cell immunity to Omicron, is likely to contribute to protection from severe COVID-19, supporting early clinical observations from South Africa. Further explanation The limited effect of Omicron’s mutations on the T cell response suggests that vaccination or prior infection may still provide substantial protection from severe disease. Indeed, South Africa has reported a lower risk of hospitalisation and severe disease compared to the previous Delta wave Cross-reactive T cell responses acquired through vaccination or infection may contribute to these apparent milder outcomes for Omicron. The resilience of the T cell response demonstrated here also bodes well in the event that more highly mutated variants emerge in the future. Learn more about your ad choices. Visit megaphone.fm/adchoices
NOW PLAYING
Omicron science, promising news
No transcript for this episode yet
Similar Episodes
Jun 30, 2026 ·98m
Jun 23, 2026 ·35m
Jun 16, 2026 ·100m
Jun 9, 2026 ·83m
May 26, 2026 ·94m