Web-Based HIV Testing in Abruzzo,Italy: Analysis of 15-Month Activity Results

Abstract

Undiagnosed cases of HIV infection in developed countries are estimated at 20–30% of individuals living with HIV. Web-based strategies may represent a new approach to easier, wider, and unrestricted access to early testing. The Abruzzo Region, Italy, developed a Web-based tool to recruit persons at high risk of HIV and other sexually transmitted infections (STIs). At the Website www.failtestanchetu.it, browsers found information on STIs (HIV, hepatitis B and C, and syphilis), a structured questionnaire called “risk calculator” to assess one's own risk behaviors and direct booking of their test at one of six sites throughout the region. The Website was advertised on local media and in pharmacies, high schools, sports facilities, and factories. Between February 1, 2014, and May 31, 2015, about 6000 users visited the Website; 3046 people attended a visit for counseling on risk behaviors, signs, or symptoms of STIs and accepted blood drawing for HIV, hepatitis B Virus (HBV), hepatitis C Virus (HCV), and syphilis tests. Fifty-eight (1.90%) subjects were positive for HCV, 56 (1.84%) for HBsAg, 90 (2.95%) for Treponema pallidum antibodies, and 28 (0.92%) for HIV. Ninety-two percent of HIV-positive patients were successfully linked to care. Late presenters were less frequent in this sample than in the population diagnosed with HIV in Italy in 2014. An overall 7% proportion of HIV, HBV, HCV, and syphilis-unaware cases were all transferred to care, with the exception of three people. HIV seropositivity among testers was higher than 2/1000, the cost-effectiveness threshold suggested for effective testing. Therefore, our Web-based unrestricted and free access methodology appears worth further and wider evaluation.

Introduction

Despite the advances in antiretroviral treatment, prevention strategies and HIV diagnostic testing technologies, the HIV epidemic is still having a relevant impact on high-income countries, with flattened incidence rates in the United States and a steady rise in Eastern Europe.¹ In the European area, including 50 countries consistently reporting data on incident cases of HIV infection, the rate of HIV diagnoses increased by 16% between 2004 and 2011, from 42,189 to 53,974 cases, with a consistent increase in sexual transmission.¹ Moreover, undiagnosed cases of HIV infection are estimated at 15–30% of individuals living with HIV in developed countries.² Simulations from mathematical models estimated rates of unaware HIV infection at 18–21% in the United States,^3,4 20% in France,⁵ 24% in the United Kingdom, 15–40% in the Netherlands,⁶ 26% in Canada,⁷ 12–23% in Australia,⁸ and 13–15% in Italy.⁹ Up to 66% of new HIV infections are attributable to transmission from people unaware of their state, undiagnosed HIV-infected subjects being more frequent among heterosexual males and men who have sex with men (MSM).^10,11 People living with undiagnosed HIV infection are likely to miss opportunities for timely access to treatment and clinical support, and to experience greater morbidity and mortality, shorter survival, poorer response to treatment, and increased healthcare costs.¹² Web-based strategies may represent a new approach to easier, wider, and unrestricted access to early testing. Using the Internet, people can become aware of their risk behaviors and directly book their test, with no or minimal risk for privacy violation and generation of personal stigma.^13,14

To increase HIV screening among high-risk groups, the Abruzzo Region (Central Italy) developed a Web-based tool, to the best of our knowledge the first in Italy with a region-wide deployment, aimed to recruit persons at high risk of HIV and other sexually transmitted infections (STIs). In this report, we present the preliminary results of the 15-month deployment of this strategy.

Methods

At the Website (www.failtestanchetu.it), information on STIs (HIV, hepatitis B and C, and syphilis), their mode of transmission, diagnosis, and therapy is available online; users are invited to visit a section called “risk calculator,” in which a structured questionnaire is proposed to assess one's own risk behaviors. This anonymous self-evaluation takes ∼10 min; after the last answer, the site returns an easy-to-interpret signal (using a street light and its color codes) for scoring the user's risk as low, medium, or high for having acquired HIV or another STI. After this passage, users scoring a yellow or red light (moderate or high risk) are invited to book their test, using the same site, thus eliminating any other health personnel filter before counseling and testing at the chosen hospital site in the region. So the Web-based access method in the present plan is not used to ease self-testing, but rather to ease access to Internet-facilitated standard STI testing. Indeed, the most innovative feature of the site is that it is directly linked with each of the six Infectious Diseases Units of the Abruzzo Region (Pescara General Hospital, Teramo General Hospital, University of L'Aquila, University of Chieti, Avezzano General Hospital, and Vasto General Hospital). Tests are free and can be booked anonymously, possibly using a nickname or a fantasy name. At each site, testing and counseling are performed in separate spaces, dedicated to both visiting and drawing blood samples; that is, after counseling and consenting to draw blood, the patient sits for blood collection with the same personnel as for counseling, without moving to laboratory facilities. At pretest counseling, individuals are interviewed about provenience, lifestyle behaviors related to HIV and STIs transmission, and previous negative testings. In particular cases, additional information on high-risk behaviors, drug injection, HIV-positive partners, and symptoms of early HIV infection is requested. Finally, details are provided on which tests are carried out, the significance of the window period for seroconversion, and how the result will be provided.

All blood samples were processed in the reference microbiology laboratory, the Virology Unit of Pescara General Hospital. Results are made available within 1 week after sampling. Blood samples are collected according to standard procedures.¹⁵ HIV Abs assays were performed with LIAISON^® XL murex HIV assay (Diasorin, Saluggia, Italy), HBsAg with LIAISON XL murex hepatitis B virus (HBV) assay (Diasorin), hepatitis B virus (HCV) Abs with LIAISON XL murex HCV Ab assay (Diasorin), and Treponema Pallidum (TP) antibodies with LIAISON Treponema Screen (Diasorin). HIV Abs positive results were confirmed by Western blot assays (Fujirebio Diagnostics, Pomezia, Italy); TP screening was confirmed by Treponema Pallidum Hemagglutination Assay (TPHA) (Biosystems, Barcellona, Spain).

The local Health and Ethics Administrative Board in Chieti-Pescara reviewed in detail the program plan, set up by the Infectious Diseases Staff in Pescara General Hospital, in collaboration with staff members in the other five participating Infectious Diseases Units. After completing the process of funding and administrative and ethical authorization, on February 1, 2014, the Web-based HIV Testing and Counseling program was made available for the whole regional population through the Website (www.failtestanchetu.it). Newspapers, radios, and televisions locally announced the program. Leaflets were distributed through all the 458 regional pharmacies, many high schools, local health services, and local hospital facilities. The project was advertised and leaflets were distributed even in factories and in gyms. Media advertising was repeated every 6 months. Preliminary results of the testing program were descriptively released to lay media after 12 and 18 months of activity and to reinforce audience adherence.

Results

Between February 1, 2014, and May 31, 2015, about 6000 users visited the Website; a few more than 5000 went through the “risk calculator” section and nearly 3500 booked their testing using the site. Among them, 3046 individuals presented for their testing: 1183 in Pescara, 513 in Chieti, 552 in Avezzano, 307 in Teramo, 272 in Vasto, and 219 in L'Aquila. Among the 3046 blood samples collected, we found 28 (0.92%) positive for HIV. All HIV-positive tests were confirmed by Western blot assays; none of the positive subjects reported a previous diagnosis of HIV. Two of them, however, failed to collect the results of testing. The remaining 26 (92.8%) were successfully linked to care and all of them were put on antiretrovirals by attending physicians at the sites of diagnosis, in accordance with current guidelines, as all of them had indications to antiretroviral treatment (Table 1). Among HIV infections, we found two patients coinfected with HCV, HBV, and syphilis; two coinfected with HCV; and one coinfected with HBV. Thanks to the special funding of the present program, the same blood samples collected were tested for HCV, HBV, and syphilis. We, therefore, found 58 (1.90%) tests positive for HCV, 56 (1.84%) for HBsAg, and 90 (2.95%) for TP antibodies. All patients were suggested immediate linkage to care; we do not have follow-up data, however, for most of them at present. Clinical and demographic characteristics, as well as CD4 T cell counts of newly diagnosed HIV patients, are reported in Table 1. Risk factors for HIV transmission were homosexual intercourse in 12 (46.0%), heterosexual intercourse in 11 (42.0%), and intravenous drug addiction in 3 (12.0%) cases. Mean CD4 T cell counts were 416 ± 206 cell/mm³, nine (37.5%) patients had CD4 T cell counts ≤350 cell/mm³, and four had (16.7%) ≤200 cell/mm³. Among these, two patients had preclinical opportunistic infections at the time of their first visit and were diagnosed as AIDS cases. Median viral load was 21,025 cp/mL (interquartile range 3644–123,300), and six (21.4%) patients had a viral load ≥100,000 cp/mL. As of CDC stage at time of diagnosis, 60.7% were in CDC class A, 10.7% in B, and 7.1% in C. Positive results for the four screened infections were evenly distributed across the study period and no suggestion of clustering in time and space emerged.

Table 1.

Clinical and Demographic Characteristics of Newly Diagnosed HIV-Positive Patients

Characteristics
Age, mean ± SD	34.6 ± 9.3
Males	20 (71.4)
Females	8 (28.6)
Heterosexual, n (%)	11 (39.3)
Homosexual, n (%)	12 (42.9)
IDU, n (%)	3 (10.7)
Patients referring for treatment, n (%)	26 (92.8)
Previously tested for HIV, n (%)	11 (39.3)
CD4 T cell counts, cell/mm³, mean ± SD	416 ± 206
CD4 T cell counts ≤350 cell/mm³, n (%)	9 (32.1)
CD4 T cell counts ≤200 cell/mm³, n (%)	4 (14.3)
Median viral load (interquartile range), cp/mL	21,025 (3644–123,300)
Stage of HIV infection, n (%)
A1	9 (32.1)
A2	6 (21.4)
A3	2 (7.1)
B2	3 (10.7)
C2	1 (3.6)
C3	1 (3.6)
Unknown	6 (21.4)
Country of origin, n (%)
Italy	22 (78)
Guinea	1
Mali	1
Nigeria	1
Romania	1
Russia	1
Unknown	1
Region of residence, n (%)
Abruzzo	19 (70)
Others	8 (30)

SD, standard deviation; IDU, injection drug user.

Discussion

An overall 7% of unaware STIs, including 0.92% of HIV infections, were found among the 3046 participating people. The rate of tests positive for HIV among recruited persons was definitely higher than 2/1000, the threshold deemed cost-effective when offering routine HIV testing.^16,17 Indeed, here we report on a much higher proportion of positive HIV tests, very close to the yields of screening programs deployed for high-prevalence areas.¹⁸ The remarkably high proportion of new HIV cases (8.8/1000 tests) sounds particularly high when compared with most recent programs in Italy and Europe, including those based on mobile testing for MSM, injection drug user (IDU), or female sex workers.^19

–24 Further, although our testing technology requested patients to come back to collect results, the proportion of people linked to care was very high (>90%).^18,22

As in many other developed countries, HIV infection is not highly prevalent in our area, and systematic screening of the general population would not be cost-effective.^18,22 Similarly, HIV testing performed in rehabilitation centers for drug addiction and STI clinics detected a low proportion of asymptomatic diagnoses in recent years, both in our country and in many other developed areas;^18,22,25 further, other screening programs at public health European institutions fell below target, likely because many undiagnosed asymptomatic HIV infected persons may have limited contact with healthcare facilities.^26,27 Screening programs targeted to high-risk groups are the most suitable, but in many international settings they proved rather inefficacious because of several limitations for the access of at-risk subjects, including low perception of risk and reluctance to participate because of fears about confidentiality.^18,19,28,29 To the best of our knowledge, our report describes the first Web-based screening program performed in Italy, at least with such a large regional design and direct Web-based booking of testing. Since people all around Europe and the United States are increasingly searching for health information on the Internet,³⁰ this may be an innovative way to propose HIV and, in general, STI testing. So far, several health projects were implemented around the word for Internet-based HIV testing of at-risk individuals.^24,31

–34 Internet-based HIV testing programs differ in eHealth (using information and communication technologies for health) mode of recruitment, counseling, and testing. Some programs implement Websites, others interactive Web pages, e-mail invitations, banners, Web chats, or Web 2.0, allowing users to interact and collaborate through social media platforms as cocreators of user-generated content.^{24,31,32,35,36} Web-based platforms in the United States,³³ EU,²⁴ and China³¹ were mainly directed toward MSM, and aimed to increasing HIV testing, linkage to care, and adherence to antiretrovirals. Some included access to HIV risk self-assessment systems.³¹ Ruutel et al., for instance, implemented a Facebook page to invite MSM individuals to HIV, Hepatitis, and other STI testing. They made available a questionnaire with 144 sociodemographic items and offered participants to visit laboratories for testing procedures.²⁴ None of these platforms, however, provided the users with the possibility of choosing site of testing, by direct Web-based booking. The program delivered by Cheng et al.³¹ in China, at variance, provided similar Internet-based STI/HIV testing tools as ours. It was targeted to MSMs, using a scenario-based application, simulating real-life HIV risk scenarios and an online risk self-assessments system. Clients were linked to an online appointment system for HIV testing in one of the three facilities in the area.³¹ Our platform is open to all at-risk populations able to browse the Web, linking the visitor to the direct booking of test, and proved effective in collecting HIV-infected subjects from all at-risk groups.

We found a surprisingly high overall STI rate of about 7%. Prevalence of syphilis in Italy is high, with 582 yearly cases recently reported per 100,000 inhabitants.¹ Data on screening for syphilis are scanty in developed countries; when syphilis was tested in venues frequented by MSM, 1–2% of new cases were found.^37,38 In our area, no data were published on the prevalence of syphilis so far; so, our program provided for the first time direct evidence that many asymptomatic persons, unaware of syphilis, are present among those engaging in behaviors at risk for HIV transmission.³⁹ Similarly, we found a high prevalence of both HBsAg antigen and HCV-Ab-positive subjects. Evidence from European programs of screening for HCV revealed rates of prevalence ranging between 0.3% and 2.0%.^40,41 A recent epidemiological survey from Abruzzo, however, reported higher prevalence of HCV antibodies, peaking to >5% in males aged 30–49 years and more than 70 years, in a large sample of patients undergoing opt-out presurgical screening, as well as a peak prevalence of 1.7% for HBsAg.⁴² Our program, therefore, provided results in line with these recent estimates.⁴² Overall, our data suggest that whenever a screening program for HIV is run, additional screenings for other STIs are likely to be cost-effective.

This study has several relevant limitations. First, the Web system failed to record HIV risk calculator results until recently, so we cannot know, at present, the proportion of people at high risk for HIV among those passing the self-evaluation step. Moreover, we have no data to perform any comparison between site users who did and those who did not book a visit. On the same line, we lack a control group including people attending routine testing in the same area of Abruzzo in the same time span, that is people accessing laboratory testing in parallel to our Web-based recruitment system; similarly, we had no way, until now, to resume data on new parallel diagnoses of HCV, HBV, and syphilis in our region.

In conclusion, our Web-based recruitment for free testing for HIV and other STIs helped to diagnose more than 7% of either HIV, HBV, HCV, or syphilis-unaware subjects from several at-risk groups. Newly diagnosed HIV cases were linked to care in a very high proportion. The long-term cost-effectiveness of this Web-based screening program may definitely be worth further and larger scale evaluation.

Footnotes

Authors Contributions

E.P., G.P., C.D., V.C., A.G., D.D.G., M.P.S., J.V., and M.P. conceived and designed the program. P.D.S., A.S., P.F., T.U., F.S., and L.P. contributed to the development of the project. E.P., G.P., and E.R. analyzed the data. E.P., G.P., and E.R. wrote the article draft.

Acknowledgments

We are greatly indebted to all physicians and nurses involved in testing and counseling activities in the sites of the six Infectious Disease Units of the Abruzzo Region. We are also indebted to the staff of the “Fondazione Camillo de Lellis per l'Innovazione e la Ricerca in Medicina” for the invaluable support to the program and for contributing to inform the local population on this innovative way of testing, contacting local newspapers, radios, and televisions for advertising programs and campaigns, and distributing leaflets to all pharmacies in the area, high schools, body-building centers, and some of the local industrial plants. P.D.S. was funded by an educational grant from the “Fondazione Camillo de Lellis per l'Innovazione e la Ricerca in Medicina” Pescara, Italy. Written informed consent was obtained from each patients for publication of data.

Author Disclosure Statement

No competing financial interest exist.

References

European Centre for Disease Prevention and Control. HIV/AIDS Surveillance in Europe. Stockholm: ECDC. Available at: http://ecdc.europa.eu/en/publications/_layouts/forms/Publication_DispForm.aspx?List=4f55ad51-4aed-4d32-b960-af70113dbb90&ID=729 (Last accessed October 5, 2016 ).

van Sighem

, Nakagawa

, De Angelis

, et al. Estimating HIV incidence, time to diagnosis, and the undiagnosed HIV epidemic using routine surveillance data. Epidemiology, 2015; 26:653–660.

Hall

, Frazier

, Rhodes

, et al. Differences in human immunodeficiency virus care and treatment among subpopulations in the United States. JAMA Intern Med, 2013; 173:1337–1344.

Campsmith

, Rhodes

, Hall

, Green

. Undiagnosed HIV prevalence among adults and adolescents in the United States at the end of 2006. J Acquir Immune Defic Syndr, 2010; 53:619–624.

Supervie

, Ndawinz

, Lodi

, Costagliola

. The undiagnosed HIV epidemic in France and its implications for HIV screening strategies. AIDS, 2014; 28:1797–1804.

van Veen

, Presanis

, Conti

, et al. National estimate of HIV prevalence in the Netherlands: Comparison and applicability of different estimation tools. AIDS, 2011; 25:229–237.

Yang

, Boulos

, Yan

, et al. Estimates of the number of prevalent and incident human immunodeficiency virus (HIV) infections in Canada, 2008. Can J Public Health, 2010; 101:486–490.

Wand

, Yan

, Wilson

, et al. Increasing HIV transmission through male homosexual and heterosexual contact in Australia: Results from an extended back-projection approach. HIV Med, 2010; 11:395–403.

Mammone

, Navarra

, Regine

, et al. Prevalence of Undiagnosed HIV in Italy at the End of 2012: An Estimate Based on Surveillance Data and Disease Stage. VI Italian Conference on AIDS and Retroviruses, Roma, 25–27 Maggio, 2014.

10.

Hall

, Holtgrave

, Maulsby

. HIV transmission rates from persons living with HIV who are aware and unaware of their infection. AIDS, 2012; 26:893–896.

11.

Marks

, Crepaz

, Janssen

. Estimating sexual transmission of HIV from persons aware and unaware that they are infected with the virus in the USA. AIDS, 2006; 20:1447–1450.

12.

Mocroft

, Lundgren

, Sabin

, et al. Risk factors and outcomes for late presentation for HIV-positive persons in Europe: Results from the Collaboration of Observational HIV Epidemiological Research Europe Study (COHERE). PLoS Med, 2013; 10:e1001510.

13.

Holt

, Rawstorne

, Wilkinson

, Worth

, Bittman

, Kippax

. HIV testing, gay community involvement and internet use: Social and behavioural correlates of HIV testing among Australian men who have sex with men. AIDS Behav, 2012; 16:13–22.

14.

Han

, Bien

, Wei

, et al. HIV self-testing among online MSM in China: Implications for expanding HIV testing among key populations. J Acquir Immune Defic Syndr, 2014; 67:216–221.

15.

Tuck

, Chan

, Chia

, et al. Standard operating procedures for serum and plasma collection: Early detection research network consensus statement standard operating procedure integration working group. J Proteome Res, 2009; 8:113–117.

16.

Rayment

, Thornton

, Mandalia

, et al. HIV testing in non-traditional settings—the HINTS study: A multi-centre observational study of feasibility and acceptability. PLoS One, 2012; 7:e39530.

17.

Paltiel

, Walensky

, Schackman

, et al. Expanded HIV screening in the United States: Effect on clinical outcomes, HIV transmission, and costs. Ann Intern Med, 2006; 145:797–806.

18.

Suthar

, Ford

, Bachanas

, et al. Towards universal voluntary HIV testing and counselling: A systematic review and meta-analysis of community-based approaches. PLoS Med, 2013; 10:e1001496.

19.

Wallace

, Li

, McDaid

. HIV prevalence and undiagnosed infection among a community sample of gay and bisexual men in Scotland, 2005–2011: Implications for HIV testing policy and prevention. PLoS One, 2014; 9:e90805.

20.

Parisi

, Soldini

, Vidoni

, et al. Cross-sectional study of community serostatus to highlight undiagnosed HIV infections with oral fluid HIV-1/2 rapid test in non-conventional settings. New Microbiol, 2013; 36:121–132.

21.

Fernandez-Lopez

, Rifa

, Pujol

, et al. Impact of the introduction of rapid HIV testing in the voluntary counselling and testing sites network of Catalonia, Spain. Int J STD AIDS, 2010; 21:388–391.

22.

Thornton

, Delpech

, Kall

, Nardone

. HIV testing in community settings in resource-rich countries: A systematic review of the evidence. HIV Med, 2012; 13:416–426.

23.

Scognamiglio

, Chiaradia

, Oldrini , et al. Outreach Program of HIV Rapid Testing Among People at Higher Risk of HIV Living in Italy: Preliminary Results VII Italian Conference on AIDS and Retroviruses, Riccione, 17–19 Maggio, 2015.

24.

Ruutel

, Lohmus

, Janes

. Internet-based recruitment system for HIV and STI screening for men who have sex with men in Estonia, 2013: Analysis of preliminary outcomes. Euro Surveill, 2015; 20:pii:21094.

25.

Camoni

, Federico

, Capelli

, et al. Few Italian drug users undergo HIV testing. AIDS Behav, 2011; 15:711–717.

26.

Valdiserri

, Holtgrave

, West

. Promoting early HIV diagnosis and entry into care. AIDS, 1999; 13:2317–2330.

27.

Kurth

, Lally

, Choko

, Inwani

, Fortenberry

. HIV testing and linkage to services for youth. J Int AIDS Soc, 2015; 18(2 Suppl 1):19433.

28.

Burke

, Sepkowitz

, Bernstein

, et al. Why don't physicians test for HIV? A review of the US literature. AIDS, 2007; 21:1617–1624.

29.

Klein

, Martin

, Quinlivan

, Gay

, Leone

. Missed opportunities for concurrent HIV-STD testing in an academic emergency department. Public Health Rep, 2014; 129(Suppl 1):12–20.

30.

Centro Studi Investimenti Sociali (CENSIS). Biomedical Monitor. 2014. Available at: www.censis.it/7?shadow_comunicato_stampa=120983 (Last accessed April 3, 2016 ).

31.

Cheng

, Cai

, Tang

, et al. Providing HIV-related services in China for men who have sex with men. Bull World Health Organ, 2016; 94:222–227.

32.

Hottes

, Farrell

, Bondyra

, Haag

, Shoveller

, Gilbert

. Internet-based HIV and sexually transmitted infection testing in British Columbia, Canada: Opinions and expectations of prospective clients. J Med Internet Res, 2012; 14:e41.

33.

Rhodes

, Vissman

, Stowers

, et al. A CBPR partnership increases HIV testing among men who have sex with men (MSM): Outcome findings from a pilot test of the CyBER/testing internet intervention. Health Educ Behav, 2011; 38:311–320.

34.

Swendeman

, Rotheram-Borus

. Innovation in sexually transmitted disease and HIV prevention: Internet and mobile phone delivery vehicles for global diffusion. Curr Opin Psychiatry, 2010; 23:139–144.

35.

Muessig

, Nekkanti

, Bauermeister

, Bull

, Hightow-Weidman

. A systematic review of recent smartphone, Internet and Web 2.0 interventions to address the HIV continuum of care. Curr HIV/AIDS Rep, 2015; 12:173–190.

36.

Gaydos

, Barnes

, Aumakhan

, et al. Can e-technology through the Internet be used as a new tool to address the Chlamydia trachomatis epidemic by home sampling and vaginal swabs?. Sex Transm Dis, 2009; 36:577–580.

37.

Kahn

, Moseley

, Thilges

, Johnson

, Farley

. Community-based screening and treatment for STDs: Results from a mobile clinic initiative. Sex Transm Dis, 2003; 30:654–658.

38.

Lambert

, Fisher

, Imrie

, et al. Community based syphilis screening: Feasibility, acceptability, and effectiveness in case finding. Sex Transm Infect, 2005; 81:213–216.

39.

Lynn

, Lightman

. Syphilis and HIV: A dangerous combination. Lancet Infect Dis, 2004; 4:456–466.

40.

Price

, Gilson

, Mercey

, et al. Hepatitis C in men who have sex with men in London—a community survey. HIV Med, 2013; 14:578–580.

41.

Schmidt

, Falcato

, Zahno

, et al. Prevalence of hepatitis C in a Swiss sample of men who have sex with men: Whom to screen for HCV infection?. BMC Public Health, 2014; 14:3.

42.

Polilli

, Tontodonati

, Flacco

, et al. High seroprevalence of HCV in the Abruzzo Region, Italy: Results on a large sample from opt-out pre-surgical screening. Infection, 2016; 44:85–91.