Aim
This study aims to assess whether there was any excess mortality among the Aboriginal and non-Aboriginal populations in the Northern Territory (NT) during the COVID-19 pandemic. Nationally and internationally, there was substantial excess mortality due to the coronavirus disease (COVID-19). It is unclear if there were excess deaths during COVID-19 in the NT among Aboriginal and non-Aboriginal populations.
Methods
A time-series analysis using death data (1997-2023) was applied to develop an excess mortality surveillance model (using Auto-Regressive Integrated Moving Average (ARIMA)) for the NT population. The death data were forecasted from 2020 to 2023, by keeping 2019 as base year for projection to ascertain the expected number of deaths. The model with the best fit was ARIMA (0,1,1). Univariate time series models with 95% and 99% projection intervals have been used for assessing the expected death for the four years starting from 2020. Excess mortality was calculated by comparing expected deaths with actual deaths. Excess mortality was calculated separately for Aboriginal and non-Aboriginal populations.
Results
The NT had a mean of 1220 deaths per year during the last 4 years, from 2020 to 2023, whereas the mean number of deaths for the same period before COVID was 1072. The total COVID-19 recorded deaths in the NT till the end of 2023 was 110. In 2022 there was a statistically significant excess mortality of 193 (P<0.01), compared with 82 recorded COVID-19 deaths. Excess mortality was significant for both the Aboriginal (N=91) and non-Aboriginal (N=102) populations in 2022. Even though some months had significant excess mortality among both Aboriginal and non-Aboriginal populations, the recorded COVID deaths were not high in these months.
Conclusion
Excess mortality was significant among Aboriginal and non-Aboriginal populations in the NT in 2022 during the COVID-19 pandemic. This was associated with the peak of COVID-19 fatalities. The ARIMA model demonstrates deviations from expected deaths and helps understand the pandemic's impact on the NT. While there were excess deaths in 2022, the lack of significant deaths in most of the months suggest public health success in reducing pandemic related shocks on the NT health system. The analysis demonstrates the true mortality burden of the pandemic on the lives of Territorian Australians and underscores the importance of excess mortality as a key indicator for public health monitoring and planning. This study helps in examining the potential undercounting of deaths caused by the pandemic and will guide policy and public health response measures.
Subject(s)