Impact of the COVID-19 pandemic on infectious diseases reporting.

Introduction: COVID-19 pandemic had impacted the reporting of notifiable communicable diseases. Since the beginning of the pandemic and the introduction of relate public health measures, notifications for most notifiable diseases have declined compared to previous years. In this study, we aim to quantify the changes in the incidences of notifiable infectious diseases during and after the pandemic in Siracusa Local Health Authority, Italy. Methods: We collected and analysed the infectious disease notifications made in two different three-years periods, 2017-2019 and 2020-2022 in Siracusa Local Health Authority, Italy. Descriptive statistics were used to find the percentages and the 95% confidence interval (CI). Exact "F-tests" was performed to compare the mean values between the studied periods to evaluate the hypothesis that the number of reported cases would not differ significantly between the two periods. Significance was assessed at the p < 0.05 level. Results: The total number of notifications significantly decreased by 69.3% in the pandemic period compared to the pre-pandemic one, with the highest reduction of air-borne transmission diseases (-86.5%), followed by food-borne diseases (-68.2%) and sexually transmitted diseases (-39.3%). Conversely, an increase in number of notifications was found only for legionellosis. Conclusions: The COVID-19 pandemic had the potential to influence communicable disease reporting at multiple points. While the effects could vary considerably, the results would be expected to reduce the number and the detection of notifiable cases. Included would be changes in exposures, diagnostic testing, reporting to public health agencies, and public health investigations.