Introduction Sarcoidosis is a rare systemic inflammatory granulomatous disease of unknown cause. It can manifest in any organ. The incidence of sarcoidosis varies across countries, and by ethnicity and gender. Delays in the diagnosis of sarcoidosis can lead to extension of the disease and organ impairment. Diagnosis delay is attributed in part to the lack of a single diagnostic test or unified commonly used diagnostic criteria, and to the diversity of disease manifestations and symptom load. There is a paucity of evidence examining the determinants of diagnostic delay in sarcoidosis and the experiences of people with sarcoidosis related to delayed diagnosis. We aim to systematically review available evidence about diagnostic delay in sarcoidosis to elucidate the factors associated with diagnostic delay for this disease in different contexts and settings, and the consequences for people with sarcoidosis. Methods and analysis A systematic search of the literature will be conducted using PubMed/Medline, Scopus, and ProQuest databases, and sources of grey literature, up to 25th of May 2022, with no limitations on publication date. We will include all study types (qualitative, quantitative, and mixed methods) except review articles, examining diagnostic delay, incorrect diagnosis, missed diagnosis or slow diagnosis of all types of sarcoidosis across all age groups. We will also examine evidence of patients’ experiences associated with diagnostic delay. Only studies in English, German and Indonesian will be included. The outcomes we examine will be diagnostic delay time, patients’ experiences, and factors associated with diagnostic delay in sarcoidosis. Two people will independently screen the titles and abstracts of search results, and then the remaining full-text documents against the inclusion criteria. Disagreements will be resolved with a third reviewer until consensus is reached. Selected studies will be appraised using the Mixed Methods Appraisal Tool (MMAT). A meta-analysis and subgroup analyses of quantitative data will be conducted. Meta-aggregation methods will be used to analyse qualitative data. If there is insufficient data for these analyses, a narrative synthesis will be conducted. Discussion This review will provide systematic and integrated evidence on the diagnostic delay, associated factors, and experiences of diagnosis delay among people with all types of sarcoidosis. This knowledge may shed light on ways to improve diagnosis delays in diagnosis across different subpopulations, and with different disease presentations. Ethics and dissemination Ethical approval will not be required as no human recruitment or participation will be involved. Findings of the study will be disseminated through publications in peer-reviewed journals, conferences, and symposia. Trial registration PROSPERO Registration number: CRD42022307236. URL of the PROSPERO registration: https://www.crd.york.ac.uk/PROSPEROFILES/307236_PROTOCOL_20220127.pdf.

Sarcoidosis is a rare systemic inflammatory granulomatous disease with broad manifestation ranging from acute epileptic seizures to fatigue and pain syndromes that are subject to the organ involved. Delays in the diagnosis of sarcoidosis are attributed to the lack of a single diagnostic test or unified commonly used diagnostic criteria, and diagnosis based on exclusion of possible alternative diagnoses. We aim to systematically review the evidence about diagnostic delay in sarcoidosis to elucidate the causes and consequences of diagnostic delay, including people with sarcoidosis’ experiences. This will inform the development of interventions, tools, and health policies aiming to improve diagnostic efficiency and patients’ experiences of sarcoidosis.

IntroductionGlobally, some studies show a resurgence of pertussis. The risks and benefits of using whole-cell pertussis (wP) or acellular pertussis (aP) vaccines in the control of the disease have been widely debated. Better control of pertussis will require improved understanding of the immune response to pertussis vaccines. Improved understanding and assessment of the immunity induced by pertussis vaccines is thus imperative. Several studies have documented different immunological outcomes to pertussis vaccination from an array of assays. We propose to conduct a systematic review of the different immunological assays and outcomes used in the assessment of the humoraland cell-mediated immune response following pertussis vaccination.Methods and analysisThe primary outcomes for consideration are quality and quantity of immune responses (humoral and cell-mediated) post-pertussis vaccination. Of interest as secondary outcomes are types of immunoassays used in assessing immune responses post-pertussis vaccination, types of biological samples used in assessing immune responses post-pertussis vaccination, as well as the types of antigens used to stimulate these samples during post-pertussis vaccination immune response assessments. Different electronic databases (including PubMed, Cochrane, EBSCO Host, Scopus and Web of Science) will be accessed for peer-reviewed published and grey literature evaluating immune responses to pertussis vaccines between 1990 and 2019. The quality of included articles will be assessed using standardised risk and quality assessment tools specific to the study design used in each article. Data extraction will be done using a data extraction form. The extracted data will be analysed using STATA V.14.0 and RevMan V.5.3 software. A subgroup analysis will be conducted based on the study population, type of vaccine (wP or aP) and type of immune response (cell-mediated or humoral). Guidelines for reporting systematic reviews in the revised 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement will be used in this study.Ethics and disseminationEthics approval is not required for this study as it is a systematic review. We will only make use of data already available in the public space. Findings will be reported via publication in a peer-reviewed journal and presented at scientific meetings and workshops.Trial registration numberCRD42018102455.