Abstract
Objective
Ageing is associated with reduced vaccine efficacy due to immunosenescence. Severe COVID-19 outcomes are associated with comorbidities prevalent in older people. We report results from the INFORM study on severe COVID-19 outcomes in vaccinated older individuals with varying numbers of comorbidities.
Methods
A retrospective observational cohort study was conducted in England using a 25% random sample from NHS databases. COVID-19-related outcomes (hospitalisations and mortality) in fully vaccinated (≥3 doses) older individuals from 1 Jan to 31 Dec 2022 are reported.
Results
Of a reference population of 7,180,205 fully vaccinated individuals ≥12 years, 2,232,140 were ≥65 years. The proportion of older people with ≥1 COVID-19 hospitalisation increased with age (≥65, 0.6%; ≥70, 0.7%; ≥75, 0.9%; ≥80, 1.2%) compared to overall population (OP, 0.2%). Incidence rates (IR) (95% CI) per 100 person years also increased with age for hospitalisation (≥65, 0.58 [0.57-0.59]; ≥70, 0.71 [0.69-0.73]; ≥75, 0.90 [0.88-0.92]; ≥80, 1.20 [1.18-1.22] versus OP, 0.22 [0.21-0.23]) and death (≥65, 0.16 [0.15-0.17]; ≥70, 0.20 [0.18-0.22]; ≥75, 0.28 [0.26-0.30]; ≥80, 0.42 [0.39-0.45] versus OP, 0.05 [0.04-0.06]).
In those ≥65, 1,375,470 were not immunocompromised (IC) but had ≥1 high-risk comorbidity (no-IC/+Com), 586,155 had neither IC or comorbidity (noIC/noCom). An increased number of comorbidities was associated with increased hospitalisation and death IRs. In those ≥65 noIC/+Com, IRs (95% CI) were 0.63 (0.61-0.65), 0.88 (0.86-0.90) and 1.25 (1.22-1.28) for hospitalisation vs 0.20 (0.17-0.23) in noIC/noCom; and 0.16 (0.14-0.18), 0.23 (0.21-0.25) and 0.32 (0.29-0.09) vs 0.06 (0.03-0.09) for noIC/noCom for death where individuals had ≥1, ≥2 and ≥3 noIC/+Com, respectively.
Conclusions
Despite vaccination, older people are at increased risk for severe COVID-19 outcomes, with higher risk associated with more comorbidities. Even older patients with no-IC conditions have increased risk, especially those with other high-risk comorbidities. Additional interventions may be required to protect older people against severe COVID-19 outcomes.