Abstract Background The magnitude and durability of immune responses to COVID-19 mRNA vaccines remain incompletely characterized in the elderly. Methods Anti-spike RBD antibodies, ACE2 competition and virus neutralizing activities were assessed in plasma from 151 healthcare workers and older adults (range 24-98 years of age) one month following the first vaccine dose, and one and three months following the second dose. Results Older adults exhibited significantly weaker responses than younger healthcare workers for all humoral measures evaluated and at all time points tested, except for ACE2 competition activity after one vaccine dose. Moreover, older age remained independently associated with weaker responses even after correction for sociodemographic factors, chronic health condition burden, and vaccine-related variables. By three months after the second dose, all humoral responses had declined significantly in all participants, and remained significantly lower among older adults, who also displayed reduced binding antibodies and ACE2 competition activity towards the Delta variant. Conclusions Humoral responses to COVID-19 mRNA vaccines are significantly weaker in older adults, and antibody-mediated activities in plasma decline universally over time. Older adults may thus remain at elevated risk of infection despite vaccination.
【저자키워드】 COVID-19, antibodies, Older adults, mRNA vaccine, humoral responses, viral neutralization, 【초록키워드】 ACE2, immune response, vaccination, Older adults, antibody, delta variant, virus, healthcare worker, mRNA vaccines, activity, vaccine dose, Adults, Neutralizing activity, Humoral response, RBD, immune responses, response, Older age, plasma, age, humoral responses, binding antibodies, risk of infection, older adult, humoral, binding antibody, COVID-19 mRNA vaccine, except for, correction, Older, COVID-19 mRNA vaccines, Participants, second dose, All participants, measure, sociodemographic factors, health condition, significantly lower, Result, tested, significantly, remained, evaluated, elevated, reduced, exhibited, characterized, magnitude, declined, variables, were assessed, 【제목키워드】 humoral immune response, COVID-19 mRNA vaccine, Older, magnitude,