A retrospective, population-based cohort study in Alberta, Edmonton, found that between late September 2021 and late January 2022, eligible unvaccinated patients with COVID-19 had a nearly 10-fold higher risk for hospitalization than did patients who were fully vaccinated with two doses. Unvaccinated patients had a nearly 21-fold higher risk than did patients who were boosted with three doses.
“We have shown that eligible nonvaccinated persons, especially in the age strata 50-79 years, accounted for 3,000-4,000 potentially avoidable hospitalizations, 35,000-40,000 avoidable bed-days, and $100–$110 million [Canadian dollars] in avoidable health care costs during a 120-day period coinciding with the fourth (Delta) and fifth (Omicron) COVID-19 waves, respectively,” wrote Sean M. Bagshaw, MD, chair of critical care medicine at the University of Alberta, Edmonton, and colleagues.
The findings were published in the Canadian Journal of Public Health.
‘Unsatisfactory’ vaccine uptake
While a previous study by Dr. Bagshaw and colleagues recently showed that higher vaccine uptake could have avoided significant intensive care unit admissions and costs, the researchers sought to expand their analysis to include non-ICU use.
The current study examined data from the government of Alberta and the Discharge Abstract Database to assess vaccination status and hospitalization with confirmed SARS-CoV-2. Secondary outcomes included avoidable hospitalizations, avoidable hospital bed-days, and the potential cost avoidance related to COVID-19.
During the study period, “societal factors contributed to an unsatisfactory voluntary vaccine uptake, particularly in the province of Alberta,” wrote the authors, adding that “only 63.7% and 2.7% of the eligible population in Alberta [had] received two (full) and three (boosted) COVID-19 vaccine doses as of September 27, 2021.”
The analysis found the highest number of hospitalizations among unvaccinated patients (n = 3,835), compared with vaccinated (n = 1,907) and boosted patients (n = 481). This finding yielded a risk ratio (RR) of hospitalization of 9.7 for unvaccinated patients, compared with fully vaccinated patients, and an RR of 20.6, compared with patients who were boosted. Unvaccinated patients aged 60-69 years had the highest RR for hospitalization, compared with vaccinated (RR, 16.4) and boosted patients (RR, 151.9).
The estimated number of avoidable hospitalizations for unvaccinated patients was 3,439 (total of 36,331 bed-days), compared with vaccinated patients, and 3,764 (total of 40,185 bed-days), compared with boosted patients.
The avoidable hospitalization-related costs for unvaccinated patients totaled $101.4 million (Canadian dollars) if they had been vaccinated and $110.24 million if they had been boosted.
“Moreover, strained hospital systems and the widespread adoption of crisis standards of care in response to surges in COVID-19 hospitalizations have contributed to unnecessary excess deaths,” wrote the authors. “These are preventable and missed public health opportunities that provoked massive health system disruptions and resource diversions, including deferral of routine health services (e.g., cancer and chronic disease screening and monitoring and scheduled vaccinations), postponement of scheduled procedures and surgeries, and redeployment of health care professionals.”
Dr. Bagshaw said in an interview that he was not surprised by the findings. “However, I wonder whether the public and those who direct policy and make decisions about the health system would be interested in better understanding the scope and sheer disruption the health system suffered due to COVID-19,” he said.
The current study suggests that “at least some of this could have been avoided,” said Dr. Bagshaw. “I hope we – that is the public, users of the health system, decision-makers and health care professionals – can learn from our experiences.” Studies such as the current analysis “will reinforce the importance of timely and clearly articulated public health promotion, education, and policy,” he added.