Increasing incidence of acute hepatitis B virus infection referrals to the Aberdeen Infection Unit: a matter for concern

 SMJ 2003 48(3): 73-75

Alexander R Mackenzie,1 Pamela J Molyneaux,2 Anthony M Cadwgan,1 Robert BS Laing,1 J Graham Douglas,1 C Christopher Smith.1

The Infection Unit1 and Dept of Medical Microbiology2, Aberdeen Royal Infirmary, Foresterhill, Aberdeen, Scotland, UK.

E-mail: a.r.mackenzie@arh.grampian.scot.nhs.uk

 

Summary

Objectives: To assess the epidemiology and clinical outcomes of acute hepatitis B virus (HBV) infections presenting to a regional Infection Unit over a ten year period - with reference to the issues of injection drug use and strategies aimed at reducing transmission, notably needle exchange and immunisation programmes.

Methods: A retrospective casenote review of all patients with acute HBV managed at the Infection Unit in Aberdeen between 1991–2000.

Results: One hundred and nineteen (119) patients with acute HBV infection were managed for during the period of review. The annual number of patients increased from a mean of 3.3/year during the years 1991-96 to 46 in 2000. The risk factors associated with HBV infection were being an injection drug user (IDU) in 57 (47.9%), heterosexual sex in 22 (18.5%), sex with an IDU in 4 (3.4%), men who had sex with men in 10 (8.4%), tattooing in 1 (0.8%), a needle stick injury in 1 (0.8%), trauma 1 (0.8%) and unknown in 23 (19.3%). Many of these patients had “dabbled” in drug use. Thirty-one (54.4%) of the IDU patients had previously been hospitalised with drug-related medical problems. Eighteen (31.6%) of the IDUs were receiving methadone at the time of presentation.

Conclusions: There is an epidemic of HBV infection in the Grampian region of Scotland currently. Forty-six (65.7%) of the 70 infected patients diagnosed during 2000 were seen at the Infection Unit. The remainder had mild or asymptomatic disease and were managed in the community. This epidemic has occurred despite extensive use of local needle exchange facilities and might reflect missed opportunities to immunise IDUs against HBV infection. A co-ordinated approach is now in place to immunise IDUs and other high-risk groups, but the use of universal immunisation demands consideration.

 

Key words:            hepatitis B virus, injection drug users, needle-exchange programmes, immunisation, vaccines.

 

Introduction

There has been a dramatic increase in the past 3 years of acute HBV infections diagnosed in Grampian.1 Many of the infections appear to be related to injection drug use, and have occurred within the city of Aberdeen. We decided to review our experience of acute HBV referrals to the Infection Unit, Aberdeen Royal Infirmary (ARI) over the past 10 years - with particular reference to the issue of injecting drug use and strategies needed to reduce HBV transmission, notably the implementation of a broadbased HBV immunisation programme in the region.

 

Methods

A retrospective casenote review was undertaken of all patients with acute HBV managed at the Infection Unit from 1st January 1991 – 31st December 2000. Acute HBV infection was defined by the presence of IgM HBV core antibody (IgM anti-HBc) in serum. Data were collected on age, gender, domicile, risk factors, duration of injecting drug misuse, methadone use, previous hospital admissions with drug related problems, co-infection with hepatitis C virus (HCV) and HIV, complications of the HBV infection, concomitant medical conditions, duration of hospital stay, time to clearance of HBsAg and follow-up (both assessed at 10 months after infection).

 

Results

One hundred and nineteen patients with acute HBV infection were managed at the Aberdeen Infection Unit during the period under scrutiny. The annual number of patients increased from a mean of 3.3/year between 1991 and 1996 to 46 in the year 2000 (Figure 1).  Ninety-eight (82.4%) patients were admitted to hospital and 21 (17.6%) managed as outpatients. The median age for all patients was 27 years (range 13-68), for inpatients 27 years (range 13-68) and for outpatients 22 years (range 17-49). There were 81 (68.1%) males and 38 (31.9%) females. One hundred and one (84.9%) of the patients lived in Aberdeen city, 11 (9.2%) in rural Aberdeenshire, 6 (5%) in Banff and Buchan and 1 (<1%) elsewhere in Scotland. The median length of in-patient stay was 5 days (range 1-37 days).

 

The risk factors associated with HBV infection are shown in Table I.

 

Table I: Risk factors associated with HBV infection in 119 patients admitted to the Infection Unit (1991 - 2000).

Risk Factor

Number

%

IDU

57

47.9

Sex with IDU

  4

  3.4

Heterosexual sex

22

18.5

Men who had sex with men

10

  8.4

Tattoo

  1

  0.8

Needle stick injury

  1

   0.8

Unknown

23

19.3

 

The median duration of injecting among IDU was 5 years (range 0.5-18) but eight (14%) of the IDUs had been injecting for less than 1 year. Eighteen (31.6%) IDUs were receiving methadone prior to attending and 26 (45.6%) were prescribed methadone during the period under our care - part of local policy. Thirty-one (54.4%) IDU had previously been in hospital with drug-related medical problems (median 2 occasions, range 1- 14). All but one of the 57 IDUs were tested for hepatitis C antibody – 24 (42.8%) were positive and 32 (57.1%) negative. None of the 30 patients tested for HIV antibody were positive.

 

Complications included encephalopathy (2), arthropathy (2), vascultits with hypertension (1), oesophageal tear (1) and urticaria (1). Co-incidental conditions were injection-related abscess (1), pneumonia (1) and pregnancy (1). None of the patients died.

 

Ninety-three (78.2%) of the cohort attended for subsequent outpatient review within 3 months but 26 (21.8%) were lost to any follow-up. Eighty (84.9%) of the 93 who attended for follow-up became HBsAg negative by the end of the study period. The median time from initial serological diagnosis to HBsAg negativity was 3 months (range 1 – 72 months). Four patients (4%) developed Chronic Hepatitis B infection: one was cured following lamivudine therapy and one is currently receiving lamivudine. One defaulted from follow-up after a pre-treatment liver biopsy and another was lost to follow-up. Nine patients (10%) failed to return after attending the initial follow-up appointment and the serological outcome is therefore not available on these.

 

Discussion

In 1991 only 5 of the 900 patients admitted to the Infection Unit had acute HBV infection.2 The dramatic increase in the number of patients seen at our Unit with acute HBV infection since then reflects the epidemic currently affecting the Grampian region (Figure 2). In 1994 there were only 6 patients diagnosed with acute HBV infection in Grampian region. The incidence remained stable until 1998 when there were 28 infections, and the numbers have increased substantially since then – with 97 patients diagnosed in 1999 (0.2/1000/year). Only a fifth of these patients are seen at the Infection Unit, the remainder being cared for in the community. All diagnoses were made on serum submitted to the Virus Laboratory at ARI for testing.

 

 The incidence of hepatitis B infection in Scotland is increasing (152 acute and newly diagnosed chronic cases in 1995, 184 in 1996, 215 in 1997, 295 in 1998 and 386 in 1999).3 This is largely due to the epidemic in Grampian, which accounted for 114 (30%) of the 386 cases in 1999.3 Until recently the incidence of acute HBV in England and Wales was declining, from 1761 cases in 1985 to 581 in 1996.4 Figures from the PHLS, however, show the incidence to be increasing, with 719 cases of acute hepatitis B diagnosed in 1998.5

 

Injection drug use was the commonest identified risk factor for HBV infection among our cohort of patients. In a review of 9252 reported cases of acute HBV in England and Wales between 1985 and 1996, the risk factors were IDU (21%), heterosexual sex (13%), sex between men (11%) and unknown (54%).4 Most infections were reported in adults aged 15-44 years (80%), and were more commonly reported in males (70%) than females (29%).

 

HBV infection is highly infectious in non-immunised individuals and common among IDUs. Acute infection can be seen as an index of new injection drug use within a community.6 Anonymized testing of saliva for previous or ongoing HBV infection among community-recruited drug injectors in London during 1992/93 showed 51.5% (1992) and 47.9% (1993) respectively to be sero-positive for total anti-HBc antibody.7 Half of the cohort were unaware that they had been infected or had had viral hepatitis. Anti-HBc positivity was most likely among older injectors with longer “injecting careers” and a history of having shared needles and syringes.

 

The alarming increase in IDUs in North-East Scotland in recent years is reflected in the increasing number of new clients attending the needle exchange centre in Aberdeen (Figure 2) and in the increased numbers of those injectors with HBV. The HBV problem locally is likely to be related to IDUs sharing injecting equipment – notably among new IDUs - as has been the experience elsewhere in Scotland6 and England.8  Forty-five percent of new IDUs in Aberdeen and 65% of those in Aberdeenshire (on whom data was available during 1999/2000) admitted to sharing equipment in the preceding month.9 Moreover, IDUs are known to share paraphernalia (spoons, filters) even when using new needles and there is evidence from Seatle that using a needle exchange facility does not protect against HBV or HCV transmission.10 The potential for the rapid spread of blood borne viruses through the sharing of “works” is, therefore, of concern and needs to be addressed.

 

There is a clear need to improve HBV immunisation take-up among IDUs living locally. Those IDUs receiving methadone prior to admission and those previously admitted to hospital with drug-related problems could have been offered immunisation at the time of that interface - as suggested in the revised guidelines on the management of drug users11 and by the Department of Health.12 Such an intervention might have prevented some of the HBV infections in our cohort of patients.

 

Targeted HBV immunisation of identified sero-negative IDUs has been suggested since 1985 - but implementation of this policy has been poor.13 Strategies to improve the delivery of HBV vaccine to IDUs have been discussed by Hepstonal14 and  pundits have proposed adoption of the WHO recommendations for universal HBV immunisation in the United Kingdom.15 Indeed, all first year secondary school pupils in the Greater Glasgow Health board area are being offered Hepatitis B immunisation during 2001-02 as a pilot study to examine the practicalities of this approach.16 But universal HBV immunisation remains a contentious issue and is not widely accepted as necessary.17  The main argument against universal immunisation is that the seroprevalence of HBV among the general UK population remains low. In a community survey of 3781 anonymized individuals in England and Wales (during 1996), 3.9% were anti-HBc antibody positive, indicating previous or current infection, while 0.37% were chronic carriers of HBV.18

 

Sexual transmission accounts for at least 30% of the HBV infections in our cohort and persons at risk through multiple sexual partners and sexual contact with IDUs clearly need to be immunised, as recommended in the Green Book.12 The Grampian Health Board is currently attempting to increase the uptake of HBV immunisation in these high-risk groups. This approach involves input from general practitioners, hospital specialists, public health professionals, those working in needle exchange facilities and opiate substitution services and genitourinary medicine clinics together with the immunisation coordinator and prison doctors. The impact of this strategy is awaited with interest. In the meantime the epidemic of hepatitis B infection in Grampian continues, with an incidence of 0.2/1000/year, lending support to those who argue for universal immunisation - at least within the region.

Acknowledgment

Luan Bruce at Drugs Action in Aberdeen for the needle exchange data.

 

References

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