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

Abstract

Background: The true burden of acute lower respiratory tract disease (aLRTD; includes acute lower respiratory tract infection [aLRTI] and presumed non-infective exacerbations of chronic lung disease and heart failure) among adults presenting to primary care, and the proportion that are potentially vaccine preventable is unknown.

Aim: To describe aLRTD incidence in adults presenting to primary care; estimate proportions caused by respiratory syncytial virus (RSV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and Streptococcus pneumoniae (SP); and investigate disease burden from patient and NHS perspectives.

Design & setting: Primary care prospective cohort study conducted in six representative general practices (total ∼86 000 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. They will be 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.

Keywords: lower respiratory tract infection; primary health care; respiratory syncytial viruses; respiratory tract diseases.

Figure 1.. Study flow diagram

^aFor adults who present to the emergency department, they will only be eligible if they are not admitted to hospital. ^bThe research team will run a search of the electronic GP records at least twice a day to identify adults with aLRTD diagnosis, symptoms, clinical findings, and/or prescribed antibiotics. They will manually review the consultation notes, including free text, and contact the patient to assess eligibility. ^cWe have approval from the Confidentiality Advisory Group to include specific groups of patients in the surveillance arm without consent, including those we are unable to contact (at least three failed contact attempts over ≥24 hours) and patients at the end of life. If a patient lacks capacity to provide consent (for example, owing to cognitive impairment or dementia), the research team will attempt to contact a family member, friend, or unpaid carer of the patient (that is, a personal consultee) to discuss the patient’s willingness to take part. If they are unable to contact a personal consultee or if the person contacted does not want to take on the role of personal consultee, the research practitioner or nurse will attempt to identify and contact a nominated consultee. ‘Medical data’ refers to routinely collected data within the electronic GP records. ^dIf a patient declines consent (or other specified cohorts of patient), descriptive data will be collected, including: screening ID, anonymous encrypted NHS number, date of eligible condition, reasons for declining to participate, eligibility, qualifying condition, severity of illness, gender, age, deprivation decile, ethnicity, whether they reside in a care home or not, whether they require a translator (and if so what language), category of patient presentation (out-of-hours GP, in-hours GP, or emergency department), whether they die within 30 days of their appointment, and, if so, whether their death was related to their qualifying illness. ^eDaily symptom diary until recovery from illness or for up to 28 days. ^fNose and/or throat, saliva, and urine samples collected on day 1. ^gFollow-up survey (on quality of life, time off work, and recovery) at 6 weeks, 8 weeks, 3 months, 4 months, 5 months, 6 months, 9 months, and 12 months (until fully recovered from illness). aLRTD = acute lower respiratory tract disease.