AUTHOR=Rodriguez Pamela E. , Silva Andrea P. , Miglietta Esteban A. , Rall Pablo , Pascuale Carla A. , Ballejo Christian , López Miranda Lucía , Ríos Antonella S. , Ramis Lila , Marro Jimena , Poncet Verónica , Mazzitelli Bianca , Salvatori Melina , Ceballos Ana , Gonzalez Lopez Ledesma María M. , Ojeda Diego S. , Aguirre María F. , Miragaya Yanina , Gamarnik Andrea V. , Rossi Andrés H. , Laboratorio SeVa Group , PAMI Group , García Diana R. Rodriguez , Bialer Magalí G. , Leone María José de , Rasetto Natalí B: , Wenker Shirley D. , Bianchimano Luciana , Cienfuegos Maria Soledad Treffinger , Hernando C. Esteban , Careno Daniel A. , Garcia Corina , Alcón Marcela Verónica , Centurión Diego Sossa , Velázquez Candela Raffo , Aztorga Noelia Inés , Solazzi Romina , Bacigaluppe Fernando Miguel , Fernández María Soledad , Salaya Hernán , Perez Eduardo TITLE=Humoral response and neutralising capacity at 6 months post-vaccination against COVID-19 among institutionalised older adults in Argentina JOURNAL=Frontiers in Immunology VOLUME=13 YEAR=2022 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.992370 DOI=10.3389/fimmu.2022.992370 ISSN=1664-3224 ABSTRACT=

The COVID-19 pandemic has particularly affected older adults residing in nursing homes, resulting in high rates of hospitalisation and death. Here, we evaluated the longitudinal humoral response and neutralising capacity in plasma samples of volunteers vaccinated with different platforms (Sputnik V, BBIBP-CorV, and AZD1222). A cohort of 851 participants, mean age 83 (60-103 years), from the province of Buenos Aires, Argentina were included. Sequential plasma samples were taken at different time points after vaccination. After completing the vaccination schedule, infection-naïve volunteers who received either Sputnik V or AZD1222 exhibited significantly higher specific anti-Spike IgG titers than those who received BBIBP-CorV. Strong correlation between anti-Spike IgG titers and neutralising activity levels was evidenced at all times studied (rho=0.7 a 0.9). Previous exposure to SARS-CoV-2 and age <80 years were both associated with higher specific antibody levels. No differences in neutralising capacity were observed for the infection-naïve participants in either gender or age group. Similar to anti-Spike IgG titers, neutralising capacity decreased 3 to 9-fold at 6 months after initial vaccination for all platforms. Neutralising capacity against Omicron was between 10-58 fold lower compared to ancestral B.1 for all vaccine platforms at 21 days post dose 2 and 180 days post dose 1. This work provides evidence about the humoral response and neutralising capacity elicited by vaccination of a vulnerable elderly population. This data could be useful for pandemic management in defining public health policies, highlighting the need to apply reinforcements after a complete vaccination schedule.