Very good. Thank you for the summarized evidence, Johanne. Maria Inês Em seg., 31 de jan. de 2022 13:11, Joanne G. De Montigny < [log in to unmask]> escreveu: > Yes, 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 email* > > > > 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 State > > > https://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, 3 > rd 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 > > > > > To leave, manage or join list: > https://listserv.yorku.ca/cgi-bin/wa?SUBED1=sdoh&A=1 > > To leave, manage or join list: > https://listserv.yorku.ca/cgi-bin/wa?SUBED1=sdoh&A=1 > > To leave, manage or join list: https://listserv.yorku.ca/cgi-bin/wa?SUBED1=sdoh&A=1