COVID-19 Research Paper Volume 14, Issue 18 pp 7193—7205

Humoral immunoresponse elicited against an adenoviral-based SARS-CoV-2 coronavirus vaccine in elderly patients

Rodrigo Hernán Tomas-Grau1, *, , Carolina Maldonado-Galdeano2, *, , Mónica Aguilar López3, *, , Esteban Vera Pingitore1, , Patricia Aznar4, , María Elena Alcorta4, , Eva María del Mar Vélez4, , Agustín Stagnetto1, , Silvana Estefanía Soliz-Santander1, , César Luís Ávila1, , Sergio Benjamín Socias1, , Dardo Costas4, , Rossana Elena Chahla3, , Gabriela Perdigón2, , Rosana Nieves Chehín1, , Diego Ploper1, , Silvia Inés Cazorla2, ,

  • 1 Instituto de Investigación en Medicina Molecular y Celular Aplicada - IMMCA (UNT-CONICET-SIPROSA), Tucumán 4000, Argentina
  • 2 Centro de Referencia para Lactobacilos – CERELA (CONICET), Tucumán 4000, Argentina
  • 3 Public Healthcare Administration (SIPROSA), Tucumán 4000, Argentina
  • 4 Néstor Kirchner Hospital, Central Public Health laboratory (LSP) (SIPROSA), Tucumán 4000, Argentina
* Equal contribution

Received: May 20, 2022       Accepted: September 5, 2022       Published: September 21, 2022
How to Cite

Copyright: © 2022 Tomas-Grau et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


The early sequencing of the SARS-CoV-2 viral genome allowed for a speedy development of effective vaccines against the virus. Nevertheless, age-related immunosenescence, the inability to mount strong immune responses, still represents a major obstacle. Here, in a group of 149 elderly volunteers (70–96 years old), evolution of the humoral immune response over time to Gam-COVID-Vac (Sputnik V), a vaccine based on heterologous recombinant adenovirus-26 (Ad26) and adenovirus-5 (Ad5) carrying the Spike genome, was analyzed by an anti-RBD ELISA. At 28 days post vaccination (dpv), a seroconversion rate of 91% was achieved, showing the importance of administering at least two doses of Gam-COVID-Vac to elicit a robust immune response, especially in elderly individuals without previous SARS-CoV-2 infection. Interestingly, IgG specific antibodies that reached their highest titers around 28 dpv (median = 740), persisted without significant decrease after 60 dpv (median = 650). After 90 dpv, IgG titers began to drop, and at 180 dpv only 44.7% of the elderly individuals remained with detectable anti-RBD IgG antibodies. No significant differences were observed in specific humoral immune responses between genders at early times point. However, at 60 dpv anti-RBD titers were more persistent in elderly females, and only dropped at 90 dpv (p < 0.0001). As expected, the highest antibodies titers were elicited in the youngest subgroup (70–74 years). Our results show that Gam-COVID-Vac was able to deal with the ageing of the immune system, eliciting a robust immune response in an elderly cohort, which lasted approximately 90 dpv at high levels, and protected against COVID-19.


RBD: Receptor binding domain; ELISA: Enzyme linked immunosorbent assay.