Impact of the COVID-19 pandemic and associated non-pharmaceutical interventions on other notifiable infectious diseases in Germany: An analysis of national surveillance data during week 1-2016 - week 32-2020

Abstract

Background: The COVID-19 pandemic and associated non-pharmaceutical interventions (NPIs) affect healthcare seeking behaviour, access to healthcare, test strategies, disease notification and workload at public health authorities, but may also lead to a true change in transmission dynamics. We aimed to assess the impact of the pandemic and NPIs on other notifiable infectious diseases under surveillance in Germany.

Methods: We included 32 nationally notifiable disease categories with case numbers >100/year in 2016-2019. We used quasi-Poisson regression analysis on a weekly aggregated time-series incorporating trend and seasonality, to compute the relative change in case numbers during week 2020-10 to 2020-32 (pandemic/NPIs), in comparison to week 2016-01 to 2020-09.

Findings: During week 2020-10 to 2020-32, 216,825 COVID-19 cases, and 162,942 (-35%) cases of other diseases, were notified. Case numbers decreased across all ages and notification categories (all p<0•05), except for tick-borne encephalitis, which increased (+58%). The number of cases decreased most for respiratory diseases (from -86% for measles, to -12% for tuberculosis), gastro-intestinal diseases (from -83% for rotavirus gastroenteritis, to -7% for yersiniosis) and imported vector-borne diseases (-75% dengue fever, -73% malaria). The less affected infections were healthcare associated pathogens (from -43% infection/colonisation with carbapenem-non-susceptible Acinetobacter, to -28% for Methicillin-resistant Staphylococcus aureus invasive infection) and sexually transmitted and blood-borne diseases (from -28% for hepatitis B, to -12% for syphilis).

Interpretation: During the COVID-19 pandemic a drastic decrease of notifications for most infectious diseases and pathogens was observed. Our findings suggest effects of NPIs on overall disease transmission that require further investigation.

Funding: The Robert Koch Institute is the National Public Health Institute of Germany, and is an institute within the portfolio of the Federal Ministry of Health.

Keywords: COVID-19; Cohort studies; Disease transmission, infectious; Epidemiology; General Practitioners; Pandemics; Public health surveillance.

Fig. 1

Relative change (%) in the number of cases in different age groups during the first months of the COVID-19 pandemic and non-pharmaceutical interventions, compared to the expected number of cases. * Statistically significant changes (p<0.05): 0–4 years −57% (95%CI: −66%; −45%); 5–14 years −47% (95%CI: −61%; −29%), 15–34 years −24% (95%CI: −45%; 4%), 35–59 years −24% (95%CI: −59%; 41%), 60–79 years −32% (95%CI: −61%; 19%), 80+ years −43% (95%CI: −64%, −9%).

Fig. 2

Temporal variation in case numbers notified in week 1 to 32 in 2020, compared to the expected case numbers, of a selection of infectious diseases under surveillance in Germany. CRE = Enterobacterales, carbapenem-non-susceptible, TBE = tick-borne encephalitis. The number of expected cases was estimated with quasi-Poisson regression analysis, using case data of week 2016–01 to 2020–09. The regression model incorporated trend and seasonal components.