Estimating the burden of vaccine preventable lower respiratory tract disease in primary care, UK: protocol for a prospective surveillance study (AvonCAP GP2).

Background: The true burden of acute lower respiratory tract diseases (aLRTD; includes acute lower respiratory tract infection, acute exacerbation of pre-existing heart failure and chronic lung disease) among adults presenting to primary care, and the proportion that are potentially vaccine preventable, is unknown.

Aims: To describe aLRTD incidence in adults presenting to primary care; estimate proportions caused by RSV, SARS-CoV-2 and pneumococcus; and investigate disease burden from patient and NHS perspectives.

Design & setting: Primary care prospective cohort study conducted in six representative General Practices (total ̴83 000 registered adults) in Bristol, UK.

Method: Adults (aged≥18 years) registered at participating General Practices and presenting to primary care (in-hours or out-of-hours) or emergency department (if not admitted) with aLRTD will be eligible and identified by real-time primary care record searches. Researchers will screen electronic GP records, including free text, contact patients to assess eligibility, and offer enrolment in a surveillance study and an enhanced diagnostic study (urine, saliva and respiratory samples; physical examination; and symptom diaries). Data will be collected for all aLRTD episodes, with patients assigned to one of three arms: surveillance, embedded diagnostic, and descriptive dataset. Outcome measures will include clinical and pathogen defined aLRTD incidence rates, symptom severity and duration, NHS contacts and costs, health-related quality of life changes, and mortality (≤30 days post identification).

Conclusion: This comprehensive surveillance study of adults presenting to primary care with aLRTD, with embedded detailed data and sample collection, will provide an accurate assessment of aLRTD burden due to vaccine preventable infections.