Real-world serological responses to extended-interval and heterologous COVID-19 mRNA vaccination in frail, older people (UNCoVER): an interim report from a prospective observational cohort study

Cohort profile:Stop the Spread Ottawa (SSO)—a community-based prospective cohort study on antibody responses, antibody neutralisation efficiency and cellular immunity to SARS-CoV-2 infection and vaccination

“…Three hundred participants in extended follow-up complete questionnaires every 6 months (months 16, 22, 28 and 34 Serological testing of monthly blood samples submitted by Surveillance cohort participants will be performed using an automated high-throughput chemiluminescent direct ELISA 80 located within the University of Ottawa. This assay has been used in several studies across Canada [86][87][88][89][90][91] and has a reported sensitivity of 100% for the spike, RBD and N protein (IgG) and false-positive rates of 2% for spike, 1% for RBD and 6% for N. 80 All viral antigens required for serological assessment and anti-human IgG-HRP (horseradish peroxidase) fusion secondary antibody are provided by Yves Durocher at the National Research Council of Canada. Proteins are expressed in a CHO-DXB11-derived clone (CHOBRI/55E1) with yields estimated at 70-100 mg/L.…”

COVID-19 immunisation in older people

“…In The Lancet Healthy Longevity , Donald Vinh and colleagues 4 conducted a large, prospective, observational cohort study in long-term care facilities in Montréal, Québec, Canada, and reported that anti-SARS-CoV-2 serological titres increased 4 weeks after the first dose of a COVID-19 mRNA-based vaccine (mRNA-1273 [Spikevax; Moderna] or BNT162b2 [Comirnaty; Pfizer–BioNTech]) and then declined up to the second dose in residents aged 65 years and older. These patterns were equally observed both after the administration of homologous or heterologous vaccination and with an extended 16-week interval between the two doses, with differences observed only by previous SARS-CoV-2 infection status.…”

“…In the medium to long run, identifying models to integrate COVID-19 vaccination into national immunisation schedules for older people is a major public health responsibility. 10 Findings from the study by Vinh and colleagues 4 on the interchangeability of COVID-19 mRNA-based vaccines and extended-dosing intervals endorse the feasibility of safe and flexible administration in the older population. 4 Additionally, the high adherence to COVID-19 vaccination reported among older adults in countries where large-scale vaccination campaigns and governmental behavioural nudges, such as the COVID pass, were put in place could be a good starting point.…”

“…10 Findings from the study by Vinh and colleagues 4 on the interchangeability of COVID-19 mRNA-based vaccines and extended-dosing intervals endorse the feasibility of safe and flexible administration in the older population. 4 Additionally, the high adherence to COVID-19 vaccination reported among older adults in countries where large-scale vaccination campaigns and governmental behavioural nudges, such as the COVID pass, were put in place could be a good starting point. The unprecedented favourable response to, and the availability of, widely accepted COVID-19 vaccines is an opportunity that must not be squandered.…”

“…Lessons learned from the COVID-19 pandemic and the results of the study by Vinh and colleagues 4 on the strategic use of vaccines in older people suggest how to effectively handle prevention as a whole. The prioritisation of recommended vaccinations among frail, older people should aim to help identify new approaches for promoting the health of this population and support efforts that contribute to healthy ageing.…”