Despite recent progress, hepatitis C virus (HCV) infection remains a global health challenge.1 The World Health Organization (WHO)’s Global Hepatitis Strategy aims to achieve a 90% reduction in new HCV infections and a 65% reduction in HCV-related mortality by 2030.2 In Europe, the incidence of HCV was estimated at 8.9 cases per 100,000 population in 2019, with a male-to-female ratio of 2.1:1.3 Between 2015 and 2019, the Strategic Plan for Tackling Hepatitis C (PEAHC, for its Spanish acronym) evaluated the prevalence and incidence of HCV in Spain, creating a registry of patients with hepatitis C and establishing measures to mitigate its impact on the National Health System.4 In a seroprevalence survey conducted between 2017 and 2018, the Spanish Ministry of Health estimated a 0.17% prevalence of active HCV infection in the general population. Among these patients, 29.4% were unaware of their infection and 63.5% had previously known exposures or risk factors.5 In a more recent study conducted in 2020, the estimated incidence of HCV in Spain was 2.4 cases per 100,000 population, mostly affecting adults aged 55–64 years.6

Screening is a fundamental tool in the fight to eliminate HCV, since it has been shown to reduce disease prevalence in its earliest stages.7 The 2018 European Centre for Disease prevention and Control (ECDC) guidelines recommend the implementation of comprehensive national testing strategies and appropriate linkage to care of individuals affected.8 Although the Spanish PEAHC plan has helped significantly in reducing the number of HCV-related hospitalizations,9 a considerable proportion of patients remain unaware of their condition.5,10

The Spanish Association for the Study of the Liver (AEEH, for its Spanish acronym) recommends testing for anti-HCV antibodies in the entire population aged between 40 and 70 years, linking to care all patients with active HCV infection.11 Several cost-effectiveness studies support the feasibility of this approach, highlighting its healthcare saving and positive impact on national productivity.12–14 Furthermore, international guidelines recommend universal HCV screening for all adults over 18.15 Numerous projects for the active retrieval and treatment of patients with HCV in Europe and Spain16–20 have demonstrated their contribution to the WHO elimination targets and the effectiveness of these approaches, despite the disruptive impact the COVID-19 pandemic.21–23

The recommendations of the 2020 Spanish Ministry of Health screening Guidelines indicate HCV testing in people with known exposures or risk factors.24 This places the emergency department (ED) in an ideal position for identifying new cases of hepatitis in this population,25,26 as high-risk groups, such as people who inject drugs or migrants from countries with high HCV prevalence, tend to seek medical care primarily through EDs due to their poor linkage to the healthcare system.27,28 In fact, recent studies on the diagnosis of HCV and other blood-borne viruses in EDs confirm that this strategy is feasible, effective and cost-effective.29–31

Although the latest HCV report from the Ministry of Health does not include data from Catalonia,6 a study conducted in patients attending the ED of a university hospital in Barcelona revealed a 0.73% prevalence of active HCV infection. Notably, 44% of the diagnosed patients were unaware of their infection and 60% had no known risk exposures.32 These findings illustrate the need to improve HCV screening in this region, especially in the setting of the ED. In this study, we analyzed the results of an opportunistic HCV screening program in the ED of Bellvitge University Hospital (HUB, for its Spanish acronym). The primary objective was to identify new patients and link them to the healthcare system.

Opportunistic screening programs, especially in EDs, help identify patients unaware of their HCV infection.8,25,26,29,30 The FOCUS program has helped not only to increase the number of serology tests performed in the target population (patients aged 30–70 years who had a blood sample taken in our ED), but also in the overall population. This has indirectly increased the screening of individuals aged<30 years and >70 years as a result of the pre-configured computer test ordering system created for the implementation of screening, which has served to expedite tests requested at the physician's discretion outside of this process (based on risk factors). Specifically, the introduction of the FOCUS project in the ED of our hospital nearly tripled the number of HCV tests compared to the previous year.

The results of our study underscore the effectiveness of opportunistic screening in identifying new HCV cases and improving the scope of diagnosis. Linkage to care is crucial to ensure that all patients diagnosed receive the necessary treatment.37 In our study, 12 of the 13 patients with active infection were linked to medical care, demonstrating the effectiveness of the follow-up system implemented. Dedicated staff played a key role in this process, ensuring that patients were properly informed and referred to the gastroenterology department.

The prevalence of active HCV infection in this study was 0.33%, which is almost twice the 0.17% prevalence estimated for the general Spanish population.24 Another opportunistic screening conducted at a university hospital in Barcelona with patients aged>16 years32 also reported a prevalence of active HCV infection (0.73%) higher than that estimated in the national seroprevalence study.24 Therefore, both studies highlight the higher proportion of previously undiagnosed infections in the population of the Barcelona metropolitan area attending EDs, revealing a significant opportunity to improve HCV detection in the general population through opportunistic screening strategies.

Analysis of patient medical records identified exposure factors or at-risk situations associated with HCV infection. In our study, 76.92% viremic patients presented risk factors such as injection or inhaled drug use and origin from countries with high HCV prevalence.33 This identifies particularly vulnerable groups in our health area and may explain the high prevalence observed in our hospital.

Additionally, the fact that over 20% of newly detected cases had no record of risk factors underlines the need to expand screening guidelines to include a broader population. Strict adherence to Ministry of Health and AEEH screening recommendations (age- and risk-based testing only)2,11 would have resulted in failure to diagnose some viremic patients in our study. This underscores the limitations in current guidelines and the need to adopt a more inclusive and proactive approach to HCV screening. In fact, liver fibrosis data revealed that a high percentage of patients had advanced fibrosis or cirrhosis at diagnosis, indicating that they were identified late in the course of the infection.38

In this regard, previous missed diagnostic opportunities were evident in our analysis. The majority of viremic patients (92.31%) had a history of previous healthcare system encounters, including multiple visits to EDs and other healthcare settings. These patients could have been diagnosed earlier should a testing procedure had been in place in these settings, highlighting the importance of implementing more comprehensive systematic screening strategies to avoid late diagnosis and improve long-term health outcomes. This is consistent with recent studies on HCV screening cost-effectivity in EDs, which demonstrate that this strategy is practical and cost-effective.29–31

Our study presents some limitations. Its unicentric nature entails that we should not extrapolate the results obtained to other places or health areas. In addition, only 26.1% of eligible patients were screened, which could introduce selection bias. Since screening was not randomized, certain patient subgroups may have been over- or underrepresented. However, this limitation is common in ED-based screening studies and is primarily due to the opportunistic nature of testing. To improve coverage and reduce clinician-dependent variability, we strongly advocate for an opt-out screening strategy (where all eligible patients are screened unless they explicitly decline) and the automation of HCV test ordering, ensuring that all eligible patients are systematically screened. This would enhance efficiency, minimize missed testing opportunities, and provide a more representative sample of the ED population.

In conclusion, HCV detection rates in the ED resulted in a significantly higher measured prevalence compared to the general population, suggesting that many infections would remain undiagnosed if only Ministry of Health screening guidelines were followed. Opportunistic ED-screening has proven to be effective in identifying more patients without disrupting workflow. Our findings support expanding screening guidelines to broader populations, optimizing efforts toward HCV elimination.

The data that support the findings of this study are available on request from the corresponding author. Data are not publicly available due to privacy or ethical restrictions.

The design of this project is based on good clinical practices, following the recommendations of the WHO and the Department of Health of the Catalan Institute of Health (ICS). This study complies, both in its composition and in its standard operating procedures, with current Spanish and European legislation. The project was carried out in accordance with the principles of the Declaration of Helsinki and complied with the European Union General Data Protection Regulation, ensuring the removal of all personal identifiers from the results.

We received funding from the Gilead Sciences FOCUS program to support viral hepatitis screening and linkage to the first medical appointment after diagnosis. FOCUS funding does not support activities beyond the first medical appointment and is agnostic as to how organizations approach subsequent patient clinical management.

Alba Carrodeguas and José Luis González-Sánchez own stock in and are employees of Gilead Sciences. The remaining authors declare no conflicts of interest associated with the research, authorship, and publication of this article. Data collection and management were conducted independently, with additional oversight from independent data monitoring agencies.