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Sustaining the impact of hepatitis B virus (HBV) vaccination on incidence and prevalence of HBV infection requires increasing and maintaining the uptake of vaccine among those at risk. In recent years, the level of vaccine uptake among people who inject drugs (PWID) in the UK has levelled-off. Data (2015-2016) from the national unlinked-anonymous monitoring survey of PWID, an annual survey that collects data from PWID across England, Wales and Northern Ireland, were used to examine HBV vaccine uptake. Data from participants who had injected drugs during the previous year were used to investigate sources of hepatitis B vaccine doses as well as factors associated with vaccine uptake. Among the 3175 anti-HBc-negative participants, 3138 (99%) reported their vaccination status; 23% (714) reported no vaccine uptake. Among those not vaccinated, 447 (63%) reported being sexually active and 116 (16%) reported sharing needles and syringes. Majority of those not vaccinated reported accessing services in the previous year that could have provided hepatitis B vaccine doses. These missed opportunities for vaccinating of PWID indicate a need for additional targeted interventions.

Monitoring infections and risk in people who inject drugs (PWID) is important for informing public health responses. In 2011, a novel hepatitis C antibody (anti-HCV) avidity-testing algorithm to identify samples compatible with recent primary infection was introduced into a national surveillance survey. PWID are recruited annually, through >60 needle-and-syringe programmes and prescribing services. Of the 980 individuals that could have been at risk of HCV infection, there were 20 (2%) samples that were compatible with recent primary infection. These were more common among: those imprisoned ⩾5 times [8/213; adjusted odds ratio (aOR) 8·7, 95% confidence interval (CI) 2·04-37·03]; women (8/230; aOR 3·8, 95% CI 1·41-10·38); and those ever-infected with hepatitis B (5/56; aOR 6·25, 95% CI 2·12-18·43). This study is the first to apply this algorithm and to examine the risk factors associated with recently acquired HCV infection in a national sample of PWID in the UK. These findings highlight underlying risks and suggest targeted interventions are needed.

People who inject drugs are vulnerable to infections and injuries at injection sites, but these have rarely been studied in those injecting image- and performance-enhancing drugs (IPEDs). This study examined the factors associated with reported symptoms of injection site infections and injuries in IPED injectors. Of the 366 male IPED injectors surveyed, 42% reported ever having redness, swelling and tenderness (36% in the preceding year), and 6·8% had ever had an abscess or open wound at an injection site. Having these symptoms was associated with a range of factors related to drug use and healthcare utilization. One sixth (17%) of those reporting redness, tenderness and swelling had ever sought treatment, as had the majority (76%) of those reporting an abscess, sore or open wound. Most common sources of advice were emergency clinics and General Practitioners. Interventions are needed to support access to appropriate injecting equipment and provide targeted harm reduction advice.

People who inject drugs (PWID) are vulnerable to infections and injuries at injection sites. The factors associated with reporting symptoms of these, seeking related advice, and hospital admission are examined. PWID were recruited in Birmingham, Bristol and Leeds using respondent-driven sampling (N = 855). During the preceding year, 48% reported having redness, swelling and tenderness (RST), 19% an abscess, and 10% an open wound at an injection site. Overall, 54% reported ⩾1 symptoms, with 45% of these seeking medical advice (main sources emergency departments and General Practitioners). Advice was often sought ⩾5 days after the symptom first appeared (44% of those seeking advice about an abscess, 45% about an open wound, and 35% for RST); the majority received antibiotics. Overall, 9·5% reported hospital admission during the preceding year. Ever being diagnosed with septicaemia and endocarditis were reported by 8·8% and 2·9%, respectively. Interventions are needed to reduce morbidity, healthcare burden and delays in accessing treatment.

The aim of this study was to estimate the amount of childhood hepatitis B virus transmission in children born in the UK, a very low-prevalence country, that is preventable only by universal hepatitis B immunization of infants. Oral fluid specimens were collected from schoolchildren aged 7-11 years in four inner city multi-ethnic areas and tested for the presence of antibody to hepatitis B core antigen (anti-HBc). Those found positive or indeterminate were followed up with testing on serum to confirm their hepatitis B status. The overall prevalence of anti-HBc in children was low [0.26%, 95% confidence interval (CI) 0.14-0.44]. The estimated average annual incidence of hepatitis B was estimated to be 29.26/100 000 children (95% CI 16.00-49.08). The total incidence that is preventable only by a universal infant immunization programme in the UK was estimated to be between 5.00 and 12.49/100 000. The study demonstrates that the extent of horizontal childhood hepatitis B virus transmission is low in children born in the UK and suggests that schools in the UK are an uncommon setting for the transmission of the virus. Targeted hepatitis B testing and immunization of migrants from intermediate- and high-prevalence countries is likely to be a more effective measure to reduce childhood transmission than a universal infant immunization programme.

An unlinked anonymous survey was conducted to measure the prevalence of selected markers for HIV, hepatitis B and C infection in recruits to the UK Armed Forces to inform future screening and hepatitis B vaccination policies. During 2007, nearly 14 000 left-over samples taken from new recruits for blood typing were collected, unlinked from identifiers and anonymously tested for HIV, hepatitis C and current and past cleared hepatitis B infection. Overall, serological evidence of HIV and hepatitis C was found in 0·06% and 0·06% of recruits, respectively. Evidence of past cleared and current hepatitis B infection was found in 3·63% and 0·37% of recruits, respectively. Overall, prevalence rates were broadly consistent with UK population estimates of infection. However, HIV and hepatitis B prevalence was higher in recruits of African origin than in those from the UK (P<0·0001). Screening for these infections is an option that could be considered for those entering Services from high-prevalence countries.

Injection site infections in injecting drug users (IDUs) are associated with serious morbidity and healthcare costs. Factors associated with symptoms of these were examined through annual (2006-2008) unlinked-anonymous survey of IDUs in England, Wales and Northern Ireland. Overall 36% (1863/5209) self-reported having a symptom with no trend over time (35% 2006, 37% 2007, 34% 2008). Symptoms were less common in the North East of England; increased with years injecting; and were higher in women, those recently homeless, those recently using a needle exchange, and those injecting both opiates and stimulants. Of those injecting during the previous 4 weeks (n=3733) symptoms were associated with: injecting daily; injecting >or=10 times a day; injecting into hands, groin, or legs; sharing filters; and reusing water to flush syringes. Symptoms of injection site infections are common in IDUs. Better-targeted preventive interventions are needed, and continued surveillance should assist with assessing the impact of new initiatives.

Hepatitis C is a global health problem and in the UK seroprevalence studies have mainly concentrated on specific high-risk groups. The aim of this study was to determine changes in the prevalence of antibody to hepatitis C virus in England using residual specimens collected between 1986 and 2000 reflecting the general population. A cross-sectional study design using a convenience collection of serum specimens from adult patients submitted to laboratories in the years 1986, 1991, 1996 and 2000 from a total of 19 laboratories around England were investigated. The main outcome was to determine anti-HCV prevalence and the average incidence occurring between 1986 and 2000 and factors associated with infection. Multivariable analysis of results from all years showed there was a significant difference in prevalence between males and females (P < 0.001), birth cohort (P < 0.001) and by health region (P < 0.001). An average of 0.72% (95% CI 0-1.65%) of those susceptible to HCV born between 1950 and 1970 were estimated to have acquired the infection between 1986 and 2000. Analysis of this convenience serum collection suggests that HCV prevalence is low in the general population, and is associated with period of birth, gender and health region. There was evidence to support a low incidence of HCV infection in those born between 1950 and 1970 over the period 1986-2000 which, at the population level, equated to a substantial burden of infection (approximately 106,000 persons). Continued surveillance and prevention targeted at injecting drug users are essential for the control of hepatitis C in the UK.

A prospective cohort study estimated the incidence of hepatitis C virus (HCV) in drug injectors in South Wales (UK). In total, 286/481 eligible seronegative individuals were followed up after approximately 12 months. Dried blood spot samples were collected and tested for anti-HCV antibody and behavioural data were collected at baseline and follow-up. HCV incidence was 5.9/100 person-years [95% confidence interval (CI) 3.4-9.5]. HCV incidence was predicted by community size [incident rate ratio (IRR) 6.6, 95% CI 2.11-20.51, P = 0.001], homelessness (IRR 2.9, 95% CI 1.02-8.28, P = 0.047) and sharing injecting equipment (IRR 12.7, 95% CI 1.62-99.6, P = 0.015). HCV incidence was reduced in individuals in opiate substitution treatment (IRR 0.34, 95% CI 0.12-0.99, P = 0.047). In order to reduce follow-up bias we used multiple imputation of missing data using switching regression; after imputation estimated HCV incidence was 8.5/100 person-years (95% CI 5.4-12.7). HCV incidence varies with community size, equipment sharing and homelessness are associated with increased HCV incidence and opiate substitution treatment may be protective against HCV.

Surveillance reports and prevalence studies have indicated that injecting drug users (IDUs) contribute more to the hepatitis C epidemic in the United Kingdom than any other risk group. Information on both the prevalence and incidence of hepatitis C in IDUs is therefore essential to understanding the epidemiology of this infection. The prevalence of hepatitis C in specimens from the Unlinked Anonymous Prevalence Monitoring Programme collected in 1995, 1996, 1998, 1999, 2000, and 2001 was determined using residual syphilis serology specimens from IDUs attending 15 genitourinary medicine (GUM) clinics in and outside London. These specimens were tested for antibodies to hepatitis C virus (anti-HCV). Using this cross-sectional design, anti-HCV-negative specimens were tested for HCV RNA to identify incident infections during the 'window' period of infection, and thus to estimate HCV incidence. Results of the multivariable analysis showed that there was marked variation in prevalence by clinic (P<0.0001) and age (P<0.0001). Overall the majority of infections were in males and the overall prevalence in injectors declined over the study period from 36.9% to 28.7%. The annual incidence in these injectors was estimated as being 3.01% (95% CI 1.25-6.73). Over the study period HCV incidence decreased by 1.2% per year. Genotyping of the incident infections identified the most common genotype as type 1 with type 3 being more frequently seen after 1998. Of the prevalent infections, genotype 1 was the most common. The study has confirmed a higher prevalence of anti-HCV in IDUs in the London area compared to those outside London. How representative of the current injecting drug user population are IDUs attending GUM clinics is unclear. Even so, such studies allow prevalence and incidence to be estimated in individuals who have ever injected drugs and inform ongoing public health surveillance.

The prevalence and genetic diversity of hepatitis C infection in women attending antenatal clinics in two regions of England was investigated to inform future surveillance and control measures. Women booking into antenatal care are routinely offered a test for immunity to rubella. Serum residues from these tests were unlinked, anonymized and archived as part of the Unlinked Anonymous Prevalence Monitoring Programme (UAPMP). The serum specimens were tested for anti-HCV using a cost-effective pooling strategy. After taking into account differential sampling from the UAPMP serum archive, the adjusted overall prevalence of anti-HCV was 0.43% (95% CI: 0.32-0.53) in London and 0.21% (95% CI: 0.14-0.28) in the Northern and Yorkshire region. Restriction fragment length polymorphism of amplified HCV RNA identified type 3a as the most common HCV genotype in these antenatal women. The prevalence of anti-HCV in antenatal women in the UK is low and consistent with that expected from injecting drug use.

Data on injecting anabolic steroid users, within the national Unlinked Anonymous HIV Prevalence Monitoring Survey of injecting drug users (IDUs) were analysed to determine their risk of acquiring blood borne viruses. One hundred and forty-nine participants who had injected anabolic steroids in the previous month were identified from 1991-6, contributing 1.4% of all participation episodes in the survey. Rates of needle and syringe sharing by steroid users were low. Three of the 149 (2.0%) had anti-HBc and none had anti-HIV in their salivary specimens. The prevalence of anti-HBc in steroid injectors was significantly lower than in heroin injectors, 275/1509 (18%) (P < 0.001), or in amphetamine injectors, 28/239 (12%) (P < 0.001). The risk of blood borne virus transmission amongst these steroid injectors is low, probably due to hygienic use of injecting equipment and low levels of sharing. It is important to distinguish steroid injectors from other IDUs because they are a distinct group in terms of lifestyle and injecting practice.

During a community-wide outbreak of hepatitis A in Gloucester, UK there was a high attack rate in children attending two city primary schools and a pre-school centre sharing the same site. In September 1990, saliva specimens were collected from 478 (85%) of the 562 children. The prevalence of antibody to hepatitis A virus (anti-HAV), as determined by saliva testing, was 29.6%; highest prevalences were seen in 5-6-year-olds and in children from that area of the city at the centre of the community-wide outbreak. The proportion of immune children with a history of clinical hepatitis varied with age from 1 in 42.7 of under-5-year-olds to 1 in 4.7 of 8-10-year-olds. Six children who received prophylaxis with human normal immune globulin (HNIG) because they were household contacts of cases subsequently became infected. Since there was evidence of transmission outside the school environment it is unlikely that a policy of universal prophylaxis within the schools would have stopped the outbreak. Mass prophylaxis in school outbreaks is only likely to be effective if most transmission is occurring at school and if the target population can be clearly defined. Salivary antibody testing is a simple, practical and acceptable procedure in young children. Salivary antibody surveys in conjunction with vaccination against hepatitis A should provide a cost-effective method for control of future outbreaks.

An outbreak of hepatitis A involved more than 50 residents of a group of villages in the late spring and summer of 1989. The only food that was common to all the laboratory-confirmed cases was bread, purchased either unwrapped or as rolls, sandwiches or filled rolls, and supplied either directly from one shop or indirectly through its subsidiary outlets. It was concluded that this bread was the most likely vehicle of transmission of the hepatitis A virus and that the bread was contaminated by soiled hands which were inadequately washed because of painful skin lesions. Comprehensive control measures were successful in limiting further spread of the infection. This outbreak highlights the transmissibility of hepatitis A virus on food. The use of disposable gloves when handling food which is to be consumed without further cooking would prevent transmission of this or other infectious agents by this route.

In March 1988 a general practitioner notified two cases of hepatitis A in a private boarding school. Epidemiological investigation, including testing for salivary antibodies revealed a further five cases and established immunity to, and recent infection with, hepatitis A virus (HAV). The pattern of the outbreak was described. A number of practices which would encourage cross-infection were corrected. Normal human immunoglobulin was given to contacts. Repeat salivary testing 10 weeks later revealed that two more boys had become reactive for anti-HAV, though at a low titre. These may have been serological responses to HAV infection modified by the passive immunization.

The consumption of bi-valve molluscan shellfish has been associated with outbreaks of viral gastroenteritis and hepatitis A. Investigations were undertaken to determine the heat inactivation conditions necessary to render shellfish such as cockles safe for the consumer. Conditions for the laboratory maintenance of live cockles are described. In preliminary experiments either poliovirus (10(6) TCID50/ml seawater) or hepatitis A virus (HAV) (approx. 10(4) RFU/ml seawater) was introduced into the shellfish tank. Following 48 h filter feeding, virus was recovered from cockles using an adsorption-elution extraction procedure. Titres of virus recovered ranged from 10(4) to 10(5) TCID50/ml of shellfish extract for poliovirus and from 10(3) to 10(5) RFU/ml of shellfish extract for HAV. Active ingestion of the virus from the seawater was demonstrated by recovering virus from within cockle guts. To quantify recovered HAV, end-point dilutions and an adaptation of a radioimmunofocus assay (RIFA) were compared. The tests were of similar sensitivity but the RIFA has the advantage of being relatively rapid, shortening the time taken to complete an experiment by as much as 4 weeks.