Surveillance of occupational exposure to bloodborne pathogens in health care workers: the Italian national programme

G. Ippolito, V. Puro, N. Petrosillo, G. De Carli and the Studio Italiano Rischio Occupazionale da HIV (SIROH) group*
Centro di Riferimento AIDS, Rome, Italy

Eurosurveillance 1999; 4: 33-6

Introduction

Health care workers (HCWs) face a serious risk of acquiring bloodborne infections, in particular hepatitis B virus (HBV), hepatitis C virus (Hepatitis C Virus), and human immunodeficiency virus (HIV), all of which are associated with significant morbidity and mortality. In 1986 the coordinating centre of the Italian study on occupational risk of HIV Infection (Studio Italiano Rischio Occupazionale da HIV, SIROH) began a multicentre prospective study to estimate the risk of transmission of HIV and other bloodborne pathogens to HCWs following an occupational exposure to blood and other body materials, and to identify high risk devices, procedures, and jobs in the health care setting. The coordinating centre has managed the Italian registry of antiretroviral post exposure prophylaxis in order to monitor the use of and the short term toxicity of zidovudine (ZDV) since 1990, and, since 1995, of antiretroviral combination prophylaxis. This paper describes the SIROH and presents results that illustrate its potential.

Methods

Hospitals are enrolled in SIROH on a voluntary basis. Participating hospitals should actively encourage reporting of exposures, and must have an employee health team. The team is in charge of the management of the exposed HCW and of data collection: i.e. interviewing the exposed HCW about circumstances of the exposure, counselling about the risk of occupational infections, offering prophylaxis, advising on the follow up schedule, investigating each incident, and recording the details of exposure.

From 1986 to 1993, all sharps injuries and contamination of non-intact skin or mucous membranes involving blood or other body materials to which universal precautions apply from sources positive for anti-HIV, anti-Hepatitis C Virus, or HBsAg were investigated in detail (1,2). In 1994, a modified version of the Exposure Prevention Information Network (EPINet) computer program developed by the Health Care

Safety Project of Virginia University (3) was adopted to record in greater detail the mechanism of all occupational exposures regardless of whether the source was identified or its infectivity established.

HBV post exposure prophylaxis (PEP) of susceptible HCWs is performed according to current protocols and HBV markers are assayed after six months. If the HCW is an HBsAg carrier, the serological status of the source patient for Delta hepatitis is ascertained and, if positive, the HCW is tested for anti-Delta antibodies after six months. With regard to Hepatitis C Virus PEP, the routine use of immunoglobulins was never recommended and is currently discouraged. HCWs exposed to Hepatitis C Virus are tested for anti-Hepatitis C Virus antibodies at baseline and after six months.

HIV PEP should begin within 24 hours of exposure, ideally within four hours, and should continue for 30 days. HIV PEP has been offered since 1990 (4). A basic regimen consisting of two reverse transcriptase inhibitors and, for higher risk exposures, an expanded treatment that includes a protease inhibitor, has been offered since 1996 (5). Italian guidelines consider that contamination of the conjunctiva with HIV infected blood poses an increased risk of transmission (6). Blood tests and a clinical examination to monitor drug toxicity and adverse reactions are performed every 10 to 15 days and continued up to 10 days after treatment is completed. Post exposure testing for anti-HIV antibodies is carried out at baseline and after six weeks, and three and six months.

Since 1989, participating hospitals have provided data on hospital resources and activities (beds, admissions, employed HCWs etc), enabling exposure rates to be calculated for the main job categories. Some hospitals provide estimates of the types of needle devices in use to assess device-specific injury rates for hollow bore needles. Device use was determined by the total purchased in one year plus the residual inventory of the previous year, minus the unused inventory of that year (7).

Results

Characteristics of participating hospitals

Overall 37 hospitals took part from 1986 to 1993, 23 of them in the expanded study of all occupational exposures (SIROH-EPINet). A further 18 hospitals were enrolled between 1994 and 1997. Thirty-three of the 41 hospitals currently taking part have an infectious diseases department and 14 are teaching hospitals. Together these hospitals have about 36 000 beds, employ 62 500 HCWs, and have notified more than 22 000 AIDS cases.

Occupational exposures

From January 1994 to June 1998, 19 860 occupational exposures were reported to the coordinating centre, 77% of which were percutaneous and 23% mucocutaneous. The rate of percutaneous/mucocutaneous exposure varied a little from year to year: 3.54 in 1994, 3.45 in 1995, 3.13 in 1996, and 3.23 in 1997. Twenty-eight per cent of all exposures were to a known infected source: Hepatitis C Virus 63%, HBV 13%, HIV 11%, and Hepatitis C Virus and/or HBV and/or HIV 13%.

Surgical departments accounted for 48% of exposures, medical departments (37%), and other areas such as intensive care units and laboratories (15%). Exposures took place mainly in the patient’s room (40%) or immediately outside (12%), and in operating theatres (20%).

Nurses were exposed in 57% of exposures, surgeons in 8%, domestic staff in 7%, and physicians in 5%. Of all exposures, 12% involved personnel in training, mostly student nurses and training doctors. Half of the exposures reported by surgeons were to sources infected with a bloodborne virus, compared with 35% for physicians, and 30% for nurses and midwives (table 1). Domestic staff were mostly exposed to unknown sources.

 Table 1 – Annual exposure rates by occupation – 1994-1996

Two thirds of the percutaneous exposures involved needle devices, sharp items 30%, glass items 2%, and human bites or scratches 2%. Forty-four per cent of the 10 122 hollowbore needlesticks were disposable syringes, 29% winged steel needles, 5% vacuum tube phlebotomy sets, 10% intravascular (IV) catheters, and 12% others. Most injuries occurred during or after use, but before disposal of the device (table 2).

Table 2: Percentage distribution of injuries according to the handling phase of devices

Seroconversion rates

No HBV seroconversions were observed during the study period out of a total of 1155 exposures to HBsAg positive sources. Of the 926 exposures reported from 1994 to 1998, 158 involved HBV susceptible HCWs, 117 of whom received active and passive immunoprophylaxis after the exposure. The transmission rate observed after mucocutaneous exposure to HIV (0.43%), was greater than after percutaneous exposure (0.14%), but the confidence intervals overlapped (table 3). Transmission rates observed for percutaneous (0.39%) and mucocutaneous (0.36%) exposure to Hepatitis C Virus were similar.

• rates were calculated on exposed health care workers followed for at least 6 months
  infect/exp = infected out of exposed health care workers
  CI = confidence interval

Antiretroviral post exposure prophylaxis

By December 1996, data on 789 individuals given PEP with ZDV monotherapy had been collected. More than 50% reported at least one adverse effect, mainly gastrointestinal, and 18% discontinued ZDV-PEP because of side effects after a mean of seven days. Most adverse effects were reported in the first week of prophylaxis (4,8). One HCW seroconverted after ZDV-PEP following conjunctival exposure to blood (9).

By June 1998, data had been collected on 103 individuals treated with two nucleoside reverse transcriptase inhibitors (NRTI) and 112 with two NRTIs plus one protease inhibitor. In the two drug group, the mean duration of treatment was 14 days; 39% of recipients reported at least one side effect, and 5% stopped the treatment because of side effects after a mean of 11 days. In the three drug group, the mean duration of treatment was 19 days, 65% of recipients reported at least one side effect, and 12% stopped the treatment because of side effects after a mean of 10 days (10). Overall PEP side effects were common, mild, and reversible.

Discussion

Effective surveillance systems for monitoring existing practices and methods and gathering information about occupational risk are essential for achieving a safer health care workplace.

This paper shows that a standardised programme can be implemented by a network of public hospitals, allowing substantial data to be collected and monitored over along period, thereby addressing many important questions about the safety of HCWs. Principal among these are rates of occupational exposures (table 1) and transmission of bloodborne pathogens (table 3). In our ongoing system, both the large study population and the long period of observation allow us to draw a more accurate ‘risk map’ of high risk areas, jobs, devices, and procedures (table 2 and figure 1), through the calculation of specific exposure rates. Furthermore, such a system helps us to monitor existing trends and identify new ones due to implementation of new measures, as well as identifying rare events that might otherwise go unnoticed.

It could be argued that hospitals enrolled on a voluntary basis are not representative of hospitals in general, but the large number of hospital beds, HCWs, and exposures reported should minimise variability that might be attributed to small numbers. The large numbers also suggest that the data are likely to represent a wide range of clinical conditions.

A second potential problem of this type of surveillance results from factors that could influence HCWs to report exposures, especially those with a low risk of infection. Efforts should be made to minimise underreporting. Laws and hospital policies providing adequate protection as well as education programmes tailored to encourage HCWs to report all exposures are needed for any surveillance system to work. Factors such as compensation, confidentiality, and job security of the HCW are assured and enforced under Italian law.

Data provided by SIROH prompted the Italian Ministry of Health to implement guidelines on occupational risk for HCWs in different settings, including universal precautions, management of bloodborne exposures, post exposure chemoprophylaxis, management of health care workers infected with bloodborne pathogens, and specific measures for dialysis, laboratories, obstetrics/gynaecology, etc. The description of exposure scenarios allows interventions to be planned, control measures to be targeted at different areas, and their effectiveness to be evaluated.

In conclusion, surveillance and research programmes of occupational exposures are needed to monitor the risk of exposure to and transmission of bloodborne pathogens, the efficacy and tolerability of post exposure treatments, and the effectiveness of safety devices and safety practices. The adoption of standardised protocols in other EU countries would enable the creation of a European network on occupational risk of HIV and other bloodborne infections for HCWs to be created, representing not only an international group of experts joined by scientific purposes, but also a joint response to the European Community requirements for a safer working environment.

 *Members of the SIROH :

Angarano G, Arici C, Arione R, Aspiro E, Baccaro C, Battistella L, Belloni AM, Berchialla I, Bergaglia M, Bergomi M, Bertucci R, Bianciardi L, Bignamini M, Bombonato M, Bonaventura ME, Bonazzi L, Bonini R, Bottura P, Burrai B, Canale M, Carniato A, Cestrone A, Chirianni A, Chiodera A, Chiriaco' P, Cocco MR, Contegiacomo P, Corradi MP, Cristini G, Crosato I, Daglio M, Dametto P, D'Anna C, De Fazio M, De Gennaro M, De Giorgis L, Desperati M, Di Bernardo L, Di Gregorio A, Di Nardo V, Di Renzo L, Evaristi C, Fasulo A, Ferrario R, Fichera MA, Finzi G, Forconi R, Francavilla E, Francesconi M, Garra L, Gherardi L, Giamperoli A, Greco G, Gualandi G, Ianeselli F, Iuliucci R, Lanave M, Libralato C, Lodi A, Lombardo M, Lorenzani M, Lubreglia G, Maccarrone S, Maggi P, Mangolini P, Marchegiano P, Masala P, Massari M, Mazzeo A, Menichetti F, Mercurio V, Micheloni G, Migliori M, Migliorino G, Milini P, Missori R, Monti A, Natalini-Raponi G, Nativi A, Nelli M, Nurra G, Orazi D, Orefice E, Orlando G, Paradiso C, Penna C, Pennesi L, Perna MC, Perosino M, Pettoello R, Piccini G, Pietrobon F, Pirazzini MC, Pischedda L, Pitzalis G, Poli C, Pompili S, Portelli V, Raineri G, Ranchino M, Raponi G, Rastrelli M, Rebora M, Regele M, Roba I, Rosati A, Ruggieri S, Ruzzenenti C, Salvi A, Scappini P, Segata A, Sfara C, Sighinolfi L, Sileo C, Simonini G, Sommella L, Soscia F, Sulas D, Suter F, Tangenti M, Tersigni I, Testini B, Toia E, Traina C, Turbessi G, Vaglia A, Vaira LM, Vlacos D, Zambuto M, Zangrando D, Zenoni S, Zullo G.

Work supported by Italian Ministry of Health, AIDS Project grants-Istituto Superiore di Sanità.

References

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