To leave, manage or join list: https://listserv.yorku.ca/cgi-bin/wa?SUBED1=sdoh&A=1Yes, I agree. Omicron, the newest variant of concern, has undergone major mutations in its spike protein and other viral proteins, hindering the binding ability of the once neutralizing antibodies present in recovered or vaccinated individuals [1]. Therefore, these antibodies can no longer adequately protect against infection (i.e., immune escape) [2]. By contrast, Redd and colleagues found that the protective memory T-cells (i.e., white blood cells) of recovered COVID-19 patients, infected with a much earlier variant (period of spring 2020) can still cross-recognize the Omicron variant, despite containing more mutations than any of the other previous variants [3]. They concluded that such T-cell responses “should provide a significant level of protection against COVID-19.”
Keeton and colleagues conducted a similar study, but included blood samples from vaccinated individuals. Even though Omicron escapes antibody neutralization in vaccinated or previously infected individuals, the T-cell-mediated immune responses to an Omicron infection were substantially preserved relative to the ancestral strain, as an indication of cross-reactivity [4]. Furthermore, these responses were of the same magnitude as those against previous variants, such as Beta and Delta, with much fewer mutations relative to that viral ancestor. These researchers affirmed the adequacy of prior vaccination or infection to reduce disease severity through this additional line of defense:
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. … The resilience of the T cell response demonstrated here also bodes well in the event that more highly mutated variants emerge in the future. [4]
Specifically, they found that the T-cells induced in infected individuals during the Beta, Delta and Omicron waves cross-recognized the spike and nucleocapsid proteins of the ancestral strain. This means that people infected with previous variants could still mount effective T-cell responses to the current, and likely, future variants.
When looking into the expanded family of coronaviruses, T-cell responses to natural infection target all the various types of proteins, such as those making up the virus’ structure: spike, nucleocapsid, membrane, and envelop. Vaccinated individuals can only mount immune defenses against the spike protein, whereas those previously infected with SARS-CoV-2 have acquired immunity against all the various types of proteins that make up this virus.
Kundu and colleagues showed that individuals with memory T-cells from previous infection with historically ubiquitous coronaviruses could cross-react with proteins of SARS-CoV-2 [5]. Of note, they found that cross-reactivity of T-cell responses against the nucleocapsid, but not the spike protein, conferred protection from viral infection.
Vaccination and recovery from a previous infection with SARS-CoV-2 can protect against severe COVID-19 symptoms, while the natural immunity acquired through viral infection has added protection benefits against infection due to broader memory T-cell responses. Nevertheless, infection may still occur, but likely with mild symptoms—so without the need to rely on hospital care. This also means further adaptation of immune responses to protect against future viral exposures.
[1] Cao, Y., Wang, J., Jian, F., Xiao, T., Song, W., Yisimayi, A., Huang, W., Li, Q., Wang, P., An, R., Wang, J., Wang, Y., Niu, X., Yang, S., Liang, H., Sun, H., Li, T., Yu, Y., Cui, Q., Liu, S., … Xie, X. S. (2021). Omicron escapes the majority of existing SARS-CoV-2 neutralizing antibodies. Nature, 10.1038/s41586-021-04385-3. Advance online publication. DOI: https://doi.org/10.1038/s41586-021-04385-3
[2] Pulliam, J.R.C. et al. (2021). Increased risk of SARS-CoV-2 reinfection associated with emergence of the Omicron variant in South Africa. medRxiv 2021.11.11.21266068. DOI: https://doi.org/10.1101/2021.11.11.21266068
[3] Redd, A. D., Nardin, A., Kared, H., Bloch, E. M., Abel, B., Pekosz, A., Laeyendecker, O., Fehlings, M., Quinn, T. C., & Tobian, A. A. (2021). Minimal cross-over between mutations associated with Omicron variant of SARS-CoV-2 and CD8+ T cell epitopes identified in COVID-19 convalescent individuals. bioRxiv 2021.12.06.471446. DOI: https://doi.org/10.1101/2021.12.06.471446
[4] Keeton, R., Tincho, M., B., Ngomti, A., … Riou, C. (2021). SARS-CoV-2 spike T cell responses induced upon vaccination or infection remain robust against Omicron. medRxiv 2021.12.26.21268380. DOI: https://doi.org/10.1101/2021.12.26.21268380
[5] Kundu, R., Narean, J. S., Wang, L., Fenn, J., Pillay, T., Fernandez, N. D., Conibear, E., Koycheva, A., Davies, M., Tolosa-Wright, M., Hakki, S., Varro, R., McDermott, E., Hammett, S., Cutajar, J., Thwaites, R. S., Parker, E., Rosadas, C., McClure, M., Tedder, R., … Lalvani, A. (2022). Cross-reactive memory T cells associate with protection against SARS-CoV-2 infection in COVID-19 contacts. Nature Communications, 13(1), 80. DOI: https://doi.org/10.1038/s41467-021-27674-x
Joanne de Montigny, PhD
From: Social Determinants of Health <[log in to unmask]> on behalf of Dennis Raphael <[log in to unmask]>
Sent: Monday, January 31, 2022 10:33 AM
To: [log in to unmask] <[log in to unmask]>
Subject: [SDOH] Merchants of herd death oversold immunity.Attention : courriel externe | external emailTo leave, manage or join list: https://listserv.yorku.ca/cgi-bin/wa?SUBED1=sdoh&A=1
https://twitter.com/yaneerbaryam/status/1487814184104517632
Merchants of herd death oversold immunity. People are being reinfected immediately again after Omicron infection. We have the data: Both laboratory experiments and actual cases.
Get a free copy of Social Determinants of Health: The Canadian Facts, 2nd edition at http://thecanadianfacts.org
Join 1200+ health leaders on the SDOH Listserv at https://listserv.yorku.ca/archives/sdoh.html
Dennis Raphael, PhD
Professor of Health Policy and Management
York University
4700 Keele Street
Strong College, Room 334
Toronto, Ontario M3J 1P3
416-736-2100, ext. 22054
email: [log in to unmask]
Website: http://health.info.yorku.ca/health-profiles/index.php?mid=162284
Of interest:
The Politics of Health in the Canadian Welfare Statehttps://www.canadianscholars.ca/books/the-politics-of-health-in-the-canadian-welfare-state
Poverty in Canada, 3rd edition,
Forewords by Cathy Crowe, Rob Ranier and Jack Layton
https://www.canadianscholars.ca/books/poverty-in-canada-d3408482-0caa-489a-8a76-7faf7587d00a
Staying Alive: Critical Perspectives on Health, Illness, and Health Care, 3rd edition
Foreword by Gary Teeple
https://www.canadianscholars.ca/books/staying-alive
Social Determinants of Health: Canadian Perspectives, 3rd edition
Forewords by Michael Butler and Maude Barlow, Carolyn Bennett and Roy Romanow
http://tinyurl.com/hm5l4hn
Immigration, Public Policy, and Health: Newcomer Experiences in Developed Nations
http://www.cspi.org/books/immigration-public-policy-and-health
About Canada: Health and Illness, 2nd edition
https://fernwoodpublishing.ca/book/about-canada-health-and-illness
Tackling Health Inequalities: Lessons from International Experiences
Foreword by Alex Scott-Samuel
http://www.cspi.org/books/tackling_health_inequalities
Health Promotion and Quality of Life in Canada: Essential Readings
http://tinyurl.com/3C8zteu
See a presentation! The Political Economy of Health Inequalities.
http://www.youtube.com/watch?v=-NCTYqAub8g
Also, presentation at the University of Toronto on how Canada stacks up again other nations in providing citizens with economic and social security.
http://vimeo.com/33346501
See what Jack Layton had to say about my books!
http://www.cbc.ca/news/canada/story/2011/04/10/cv-election-ndp-layton-platform.html
at 27:20