Investigators from the Canadian Immunization Research Network (CIRN), including CITF-funded researchers Drs. Jeffrey Kwong and Kumanan Wilson, provided epidemiological baseline rates of mortality and hospitalization to study COVID-19 outcomes in nursing home residents in Ontario. In a manuscript recently published in Vaccines, the researchers noted that the end of 2020 marked a return to pre-pandemic baseline death rates after a major increase in the death rate during wave 1 of the pandemic.
To assess vaccine safety, rates of mortality and hospitalization (by any cause) are often compared before and after vaccine roll out. However, during an evolving pandemic, hospitalization rates may be affected because people may be less willing to go to hospital for fear of contracting the infection. During wave 1 of the COVID-19 pandemic, hospitalization and emergency department visits decreased compared to the previous ten (pre-pandemic) years (2010-2019), reasons likely being fear of contracting the virus at hospital, but also due to provincial government policies on long-term care residents being sent to hospital to ensure the hospital system was not overwhelmed.
- From January 1, 2010 through December 31, 2019, there were on average over 80,000 Ontarians living in nursing homes in any given month, with an average of 2.3 deaths, 3.1 hospitalizations, and 3.6 emergency department (ED) visits per 100 residents per month. Mortality rates were higher among men and residents over 80 years.
- The number of nursing home residents declined steadily from May 2020 (under 78,000) to October 2020 (73,500).
- A higher overall mortality rate was noted in April and May 2020 (4 and 3.4 per 100 residents per month, respectively). These marked differences coincided with heightened COVID-19 infection rates.
- Hospitalization and ED visits declined from February 2020 onwards, with the lowest records observed in April 2020 (just over 1.5 and 1 per 100 residents per month, respectively).
- Mortality remained higher for men and older residents (>80 years), independent of the time period assessed.
The results indicate that the mortality rate of long-term care residents spiked during the early phase of the COVID-19 pandemic, independent of age and sex, but that it returned to a rate closer to pre-pandemic times from August to October 2020. Additionally, their analysis acknowledged a decline in hospitalizations and ED visits from Ontarians living in nursing homes during 2020, as compared to 2010-2019. The authors attributed this to a potentially increased unwillingness to seek hospital-based care for non-COVID-19-related issues during the beginning of the first pandemic wave.
Sundaram M, Nasreen S, Calzavara A, He S, Chung H, Bronskill SE, Buchan SA, Tadrous M, Tanuseputro P, Wilson W, Wilson S, Kwong JC. Background rates of all-cause mortality, hospitalizations, and emergency department visits among nursing home residents in Ontario, Canada to inform COVID-19 vaccine safety assessments. Vaccine, 39 (2021) 5265-5270. Doi: https://doi.org/10.1016/j.vaccine.2021.07.060