Older Adults Remain at High Risk for Hospitalization or Death if Infected with COVID-19

In a study conducted in the Lower Mainland of British Columbia, researchers found that 80% of individuals infected with SARS-CoV-2 were at low risk of developing severe outcomes, compared to older individuals that were not infected. Published in the Canadian Medical Association Journal, the researchers noted that the oldest uninfected individuals were at high risk of hospitalization and death caused by COVID-19.¹

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Multiple population-based cross-sectional serosurveys were managed by researchers to evaluate the estimated per infection risk of hospital admission and death. Starting at the sixth survey, 10%, 40% and 60% of individuals were infected with SARS-CoV-2. Prior to the ninth and tenth surveys, the researchers aimed to determine the risk of severe outcomes from the first-ever COVID-19 infection during the intersurvey.²

"First-ever SARS-CoV-2 infections among older adults may still contribute to substantial COVID-19 burden, reinforcing the importance of their continued prioritization for vaccination and their consideration in health care system planning," said Danuta Skowronski, PhD, lead investigator, BC Centre for Disease Control and the University of British Columbia, Vancouver, BC, with coauthors, in a press release.

The study authors noted that they used cumulative infection-induced seroprevalence, population census, discharge abstract, and vital statics data sets to aid the assessment of estimated infection hospitalization rates (IHRs) and fatality ratios (IFRs) by age and sex of individuals.¹

Through the data, the researchers found that by July of 2023, more than 80% of children and adults younger than 50 years old had been infected with SARS-CoV-2 but had low risk of a severe outcome. However, in the same period, more than 40% of adults 80 years and older had never been infected with SARS-CoV-2 but had the highest risk of hospitalization and death.¹

“During the eighth to ninth period, we estimated about 1 hospital admission for COVID-19 per 300 newly infected children younger than 5 years versus about 1 per 30 newly infected adults aged 80 years and older, with no deaths from COVID-19 among children but about 1 death per 80 newly infected adults aged 80 years and older during that period,” said the study authors in a press release.¹

The study authors noted that the researchers used data between July and December of 2022 and estimated that risk was 10 times higher in adults 80 years and older, compared to younger adults.¹

The findings suggest that COVID-19 infections among older adults remain severe, supporting the need to prioritize the oldest adults at risk for immunizations. The press release noted this age group should be considered in health care system planning.²

"Our estimates of the risk of hospital admission or death from a first-ever SARS-CoV-2 infection were low overall but derived in a highly vaccinated population. Risks are anticipated to be greater among unvaccinated and lower among previously infected groups of patients, with the lowest risk among those who are both vaccinated and previously infected," said the study authors in a press release.

References

1. Risk of hospital admission and death from first-ever SARS-CoV-2 infection by age group during the Delta and Omicron periods in British Columbia, Canada. Canadian Medical Association Journal. News release. October 30, 2023. Accessed November 3, 2023. https://www.cmaj.ca/content/195/42/E1427#msdynttrid=PfiH4CPdo16WO-q3D3qzm8-_DgCReBOS_8CRJymUZOY
2. Risk of admission and death from COVID-19 low overall, but oldest adults remain vulnerable. EurekAlert!. News release. October 30, 2023. Accessed November 3, 2023. https://www.eurekalert.org/news-releases/1005760.