HOSPITILISATIONS FOR NOROVIRUS DECREASE DURING THE COVID-19 PANDEMIC

ABSTRACT

Background Gastrointestinal infections cause a significant burden to the Australian healthcare system each year, with acute gastroenteritis infections costing up to $359 million AUD ($258 million USD) in 2016. Viral causes of gastroenteritis, particularly Norovirus, account for the majority of these cases. Given the contagious nature of many causes of bacterial and viral gastroenteritis, it was hypothesized that widespread lockdowns and increased public health focus on regular hand hygiene would contribute to a reduction in hospital presentations with gastrointestinal infections. Melbourne, Victoria, Australia first went into lockdown in March 2020 and remained in various forms of lockdown until late 2020. Methods A retrospective study comparing rates of hospitalization for bacterial and viral gastroenteritis was performed at The Royal Melbourne Hospital between February-August in both 2019 and 2020. Rates of admission were compared between the two years, as well as the causative organism and the outcome of the presentation. Descriptive statistics were provided to summarise demographic characteristics. Outcomes between the two years were compared using paired t-tests for continuous variables and Pearson chi-square for categorical variables. All data analysis was performed using Stata 16.1 and p-values £0.05 were considered statistically significant. Results Demographic data are summarised in Table 1. 283 patients were hospitalized with gastroenteritis in 2019 pre-pandemic, compared to 147 in 2020 during the COVID-19 pandemic. There was a significant reduction in the number of patients admitted with positive fecal cultures from 2019 to 2020 (87 vs 57, p < 0.01). The number and percentage of patients presenting with Norovirus reduced by greater than 90% in 2020 compared to 2019 (Table 2) (Odds Ratio 0.093 [Confidence Interval 0.02-0.41], p<0.01). There was a reduction in the number of presentations with Salmonella, however, this did not reach statistical significance (p=0.50). The number of patients presenting with Clostridium difficile significantly increased in 2020 compared to 2019 (21 versus 25, p=0.01) (Table 2). Rates of antibiotic treatment and intensive care admission were greater in 2020 compared to 2019 however there was no significant difference in biomarkers, length of stay, or mortality (Table 2). Conclusion A significant decrease in the incidence of hospitalization secondary to acute gastrointestinal infections was observed during the COVID-19 pandemic. Norovirus presentations decreased by greater than 90% between 2019 and 2020. The rate of other GI infections was similar between pre-pandemic and pandemic time points. These findings suggest that public health measures, such as social distancing and hand hygiene, may be a useful adjunct to prevent Norovirus infections in the future and could result in significant healthcare savings.(Table Presented)TABLE 1 PATIENT DEMOGRAPHICS(Table Presented) TABLE 2 GASTROINTESTINAL CULTURE POSITIVE INFECTIONS 2019 VERSUS 2020