Geriatric risk and protective factors for serious COVID-19 outcomes among older adults in Shanghai Omicron wave

Abstract

Shanghai has been experiencing the Omicron wave since March 2022. Though several studies have evaluated the risk factors of severe infections, the analyses of BA.2 infection risk and protective factors among geriatric people were much limited. This multicentre cohort study described clinical characteristics, and assessed risk and protective factors for geriatric Omicron severe infections. A total of 1377 patients older than 60 were enrolled, with 75.96% having comorbidities. The median viral shedding time and hospitalization time were nine and eight days, respectively. Severe and critical were associated with longer virus clearance time (aOR [95%CI]:0.706 (0.533–0.935), P = .015), while fully vaccinated/booster and paxlovid use shortened viral shedding time (1.229 [1.076–1.402], P = .002; 1.140 [0.019–1.274], P = .022, respectively). Older age (>80), cerebrovascular disease, and chronic kidney disease were risk factors of severe/critical. Fully vaccination was a significant protective factor against severe infections (0.237 [0.071–0.793], P = .019). We found patients with more than two comorbidities were more likely to get serious outcomes. These findings demonstrated that in the elderly older than 60 years old, older age (aged over 80), cerebrovascular disease, and chronic kidney disease were risk factors for severe infection. Patients with more than two comorbidities were more likely to get serious outcomes. Fully vaccinated/booster patients were less likely to be severe and vaccinations could shorten viral shedding time. The limitation of lacking an overall spectrum of COVID-19 infections among elders could be compensated in other larger-scale studies in the future.

Older age and depressive state are risk factors for re-positivity with SARS-CoV-2 Omicron variant

“…Older adults often have more comorbidities; poor nutrition; and poor heart, lung, and kidney function, resulting in their low natural immunity and susceptibility to viruses (9). Although previous studies have suggested that Omicron has an immune evasion effect on vaccines or antibodies from previous infections (11)(12)(13), the infection and severe illness rates increase drastically when the patient is not vaccinated (8,10). In this study, there was no statistically significant difference in vaccination status (35 unvaccinated persons) (P = 0.058), which may be related to the smaller sample size.…”

“…Although incidences of severe illness and mortality induced by Omicron were lower than previous variants, it was more transmissible and less well-controlled by vaccination ( 6 , 7 ). The high infectivity made the Omicron threaten more people, especially for elderly ( 8 , 9 ), and one study have demonstrated that rate of severe illness would not be decreased for some population without vaccination ( 10 ). Experimental studies show that Omicron has many mutations in its structure compared with SARS-CoV-2, which increases the risk of reinfection ( 2 , 11 – 13 ).…”

“…Some institutions estimate that the actual infection rate is higher ( 15 ), and compared with the Delta variant, the risk of reinfection with Omicron increases nearly 18 times ( 16 ). Considering such a high rate of infectivity and reinfection, if positive patients and susceptible populations such as older adults are not controlled in advance, Omicron will proliferate and over-burden the medical system, resulting in an increased number of deaths ( 8 , 10 ). Therefore, it is necessary to identify risk factors for patients' re-positivity.…”

The Risk of Hospitalization and Mortality After Breakthrough SARS-CoV-2 Infection by Vaccine Type: Observational Study of Medical Claims Data

“…A number of studies have found that age has a direct effect on the risk of severe COVID-19 disease [ 22 , 23 ]. We find that the proportion of the elderly cohort in our data set who were hospitalized is much higher than the proportion of the younger cohort (Figure S7 in multimedia Appendix 1).…”

“…Our findings comparing vaccine types are similar to those reported by the Centers for Disease Control and Prevention for mortality but provide additional information by vaccine type [ 1 , 16 ]. There have been several studies on individual risk factors such as age [ 22 ], specific comorbidities [ 7 ], focused populations such as Veterans [ 24 ], or large-scale projects such as OpenSAFELY, which involved 17 million unvaccinated patients [ 10 ]. Our work advances this body of literature by analyzing vaccine type, age, sex, and 39 different comorbidities in a large cohort of breakthrough patients from the general US population.…”