To investigate vaccination coverage for influenza and COVID-19 in the SARS-CoV-2 immunity and reinfection evaluation (SIREN) study cohort of healthcare workers (HCWs) between 2020 and 2023 and explore vaccination enablers and barriers.

A mixed-methods study nested within SIREN, a multicentre prospective cohort study of HCWs across the UK. Quantitative and qualitative methods were used sequentially, using an expansion/explanation function, enabling emergent themes observed from the quantitative stage to be explored in the qualitative stage.

SIREN sites include secondary care centres and community mental health trusts in the UK.

Quantitative analysis was conducted on data from 6048 participants. Participants were representative of the HCW workforce, with the majority being women (83%) and of white ethnicity (88%). Nurses made up the largest occupational group (33%). Qualitative analysis of data from 24 participants including five focus groups (n=21) and three semistructured interviews (n=3); 82% women, 26% minority ethnic, all working age from across the UK.

Quantitative: vaccine coverage for COVID-19 and influenza vaccines by demographic with multivariable logistical regression used to assess differences. Qualitative: thematic analysis to explore reasons behind the results seen in the quantitative stage.

COVID-19 vaccination was initially high; 97% received two doses and 94% a first booster. However, coverage was reduced to 77%, for the second booster. Influenza vaccination coverage was lowest in 2020–2021 (46%), increasing to 73% in 2021–2022 and to 79% in 2022–2023. In 2022–2023, vaccination coverage was higher for influenza than for COVID-19. High vaccine coverage for both COVID-19 and influenza was observed in doctors, pharmacists and therapists. Porters, healthcare assistants and staff from minority ethnic groups had lower vaccine coverage for both COVID-19 and influenza. Four themes were identified: (1) attitudes towards vaccination changed throughout the COVID-19 pandemic; (2) HCWs used data to inform vaccination decisions; (3) poor communication in healthcare settings contributed to a reduction in vaccination; (4) there were both positive and negative impacts of the COVID-19 vaccine on influenza vaccine uptake and other vaccination programmes.

Between 2020 and 2023 in our cohort, COVID-19 vaccination coverage decreased, whereas influenza increased. Our study found attitudes to both vaccines have shifted, becoming more favourable to influenza and less to COVID-19 boosters. Barriers to COVID-19 boosters, including concerns about side effects and vaccine effectiveness, need to be addressed with improved communication on the benefits and adverse events. Future vaccination strategies should address the differences we have identified in vaccine coverage across demographics and occupational groups, including continued efforts to improve vaccine equity.

ISRCTN11041050.

To integrate the quantitative and qualitative data collected as part of the PEACH (Procalcitonin: Evaluation of Antibiotic use in COVID-19 Hospitalised patients) study, which evaluated whether procalcitonin (PCT) testing should be used to guide antibiotic prescribing and safely reduce antibiotic use among patients admitted to acute UK National Health Service (NHS) hospitals.

Triangulation to integrate quantitative and qualitative data.

Four data sources in 148 NHS hospitals in England and Wales including data from 6089 patients.

A triangulation protocol was used to integrate three quantitative data sources (survey, organisation-level data and patient-level data: data sources 1, 2 and 3) and one qualitative data source (clinician interviews: data source 4) collected as part of the PEACH study. Analysis of data sources initially took place independently, and then, key findings for each data source were added to a matrix. A series of interactive discussion meetings took place with quantitative, qualitative and clinical researchers, together with patient and public involvement (PPI) representatives, to group the key findings and produce seven statements relating to the study objectives. Each statement and the key findings related to that statement were considered alongside an assessment of whether there was agreement, partial agreement, dissonance or silence across all four data sources (convergence coding). The matrix was then interpreted to produce a narrative for each statement.

To explore whether PCT testing safely reduced antibiotic use during the first wave of the COVID-19 pandemic.

Seven statements were produced relating to the PEACH study objective. There was agreement across all four data sources for our first key statement, ‘During the first wave of the pandemic (01/02/2020-30/06/2020), PCT testing reduced antibiotic prescribing’. The second statement was related to this key statement, ‘During the first wave of the pandemic (01/02/2020-30/06/2020), PCT testing safely reduced antibiotic prescribing’. Partial agreement was found between data sources 3 (quantitative patient-level data) and 4 (qualitative clinician interviews). There were no data regarding safety from data sources 1 or 2 (quantitative survey and organisational-level data) to contribute to this statement. For statements three and four, ‘PCT was not used as a central factor influencing antibiotic prescribing’, and ‘PCT testing reduced antibiotic prescribing in the emergency department (ED)/acute medical unit (AMU),’ there was agreement between data source 2 (organisational-level data) and data source 4 (interviews with clinicians). The remaining two data sources (survey and patient-level data) contributed no data on this statement. For statement five, ‘PCT testing reduced antibiotic prescribing in the intensive care unit (ICU)’, there was disagreement between data sources 2 and 3 (organisational-level data and patient-level data) and data source 4 (clinician interviews). Data source 1 (survey) did not provide data on this statement. We therefore assigned dissonance to this statement. For statement six, ‘There were many barriers to implementing PCT testing during the first wave of COVID-19’, there was partial agreement between data source 1 (survey) and data source 4 (clinician interviews) and no data provided by the two remaining data sources (organisational-level data and patient-level data). For statement seven, ‘Local PCT guidelines/protocols were perceived to be valuable’, only data source 4 (clinician interviews) provided data. The clinicians expressed that guidelines were valuable, but as there was no data from the other three data sources, we assigned silence to this statement.

There was agreement between all four data sources on our key finding ‘during the first wave of the pandemic (01/02/2020-30/06/2020), PCT testing reduced antibiotic prescribing’. Data, methodological and investigator triangulation, and a transparent triangulation protocol give validity to this finding.

ISRCTN66682918.