Community rates of Covid-19 were the key determinant of Covid outbreaks in long-term residential care homes during the first year of the pandemic in Ireland, a new study has shown.

According to researchers from the Economic and Social Research Institute (ESRI), long-term residential care homes “were at the centre of the Covid-19 pandemic”. A substantial proportion of Covid-related deaths were linked to outbreaks in these homes in Ireland and other countries.

Internationally, a range of factors have been found to be associated with such outbreaks, including facility size, form of ownership and community rates of Covid-19. The ESRI researchers set out to examines the specific factors associated with Covid-19 outbreaks in these homes in Ireland during the first three waves of the pandemic.

They matched data on Covid-19 in long-term residential care homes and non-care home settings with information on care home characteristics. These data allowed the researchers to track Covid-19 outbreaks and assess the severity of each outbreak in terms of cases and deaths across all long-term residential care homes between March 2020 and March 2021.

The study found that two-thirds of all of these homes had at least one Covid-19 outbreak during the study period. In total, there were over 8,500 confirmed Covid-19 cases among long-term residential care home residents and over 2,100 deaths.

The researchers found no difference between public and private care homes in terms of the probability of an outbreak occurring, although they did find that larger care homes were 2.5 times more likely to have a Covid-19 outbreak.

However, being located in a county with high community rates of Covid-19 was found to have the largest association with the probability of a Covid-19 outbreak. The researchers estimated that care homes located in counties with the highest community rates of Covid-19 were seven times more likely to have an outbreak compared to care homes located in counties with the lowest rates.

Overall, community Covid-19 rates were positively associated with larger outbreaks and outbreaks with higher Covid-19 mortality.

“These findings show the devastating impact Covid-19 had on long-term residential care homes in Ireland in terms of cases and deaths. We find that community rates of Covid-19 were the key determinant of Covid-19 outbreaks in these homes in Ireland, in line with findings from the Health Protection Surveillance Centre and the Health Information Quality Authority. The results also align with international evidence,” the researchers said.

They added that these results “should inform the understanding of the factors associated with Covid-19 and provide lessons on how to mitigate the impact of future waves of Covid-19 or other infectious diseases”.