The impact on primary care of a large waterborne campylobacter outbreak in Norway: a controlled observational study.

Objective: Document the impact of an outbreak of gastroenteritis on local primary health care services, compared to a control period.

Design: Controlled observational study with data from the outbreak and a control period. Data obtained from electronic medical records (EMR) of general practitioners (GPs) and the out-of-hours (OOH) service. Telephone data from the OOH service's telephone records.

Setting: Campylobacteriosis outbreak in Askøy municipality, Norway in 2019. Over 2000 individuals were infected.

Subjects: Patients in contact with GPs and the OOH service during the outbreak and a control period.

Main outcome measures: Patient contacts with GPs and the OOH service during the outbreak and a control period.

Results: There was a 36% increase in contacts during the outbreak compared to the control period (4798 vs. 3528), with the OOH service handling 78% of outbreak-related contacts. Telephone advice was the dominant method for managing the increase in contacts to primary care, both in OOH services and daytime general practice (OR 3.73 CI: [3.24-4.28]). Children aged 0-4 years had increased use of primary care during the outbreak (OR 1.51 CI: [1.28-1.78]). GPs referred 25% and OOH services referred 75% of 70 hospitalized cases.

Conclusion: The OOH service handled most of the patients during the outbreak, with support from daytime general practice. The outbreak caused a shift towards telephone advice as a means of providing care. Young children significantly increased their use of primary care during the outbreak.