439
AIDS CARE, VOL. 3, NO. 4, 1991
HIV infection in injecting drug users A. DURANTE Public Health Laboratory Service, 61 Colindale Avenue, London NW9 SEQ, UK
Introduction There were no great surprises in the field of HIV epidemiology in injecting drug users at the Seventh International Conference on AIDS in Florence this year. Instead, the research findings presented tended to clarify and broaden our understanding of the concepts already existing in the field. Some gaps in the picture of worldwide HIV prevalence and infection rates were filled. The potential for the spread of HIV in prisons was documented. Behaviour patterns associated with transmission were further examined and quantified. The progression of HIV was observed. Prevalence studies To determine the extent of HIV infection in injecting drug users, prevalence surveys have been undertaken throughout the world. Haw (WC3049) reported a prevalence of 1.5% in 500 injecting drug users in and out of treatment in Glasgow. A 1.2% prevalence was found by Durante (WC3343) between December 1989 and March 1991 from a sample of 1,868 injecting drug users attending a variety of drug services in England and Wales. Crosier (MC48) reported a prevalence of 13% from a sample of 534 injecting drug users recruited from within treatment and outside treatment in London. The Crosier and Haw surveys were part of the European Community serial point preva-
lence survey which presented its first year’s results at this conference. In this survey, Spain reported the highest prevalence at 50% and Greece the lowest at 2% (Seyrer, THCSO). After a rapid increase between 1987 and 1988, the prevalence in Bangkok seems to have become stable at around 32-44% (Choopanya, Community Responses to AIDS, Parallel Session). The Soviet Union reports having found no cases of HIV among injecting drug users to date (Sauchenko, WC3365). A prevalence of 57% was found among IDUs in the state of Sao Paul0 in Brazil in 1990 (Mesquita, MC3008). A rate of 2% prevalence was found in injecting drug users in a methadone treatment clinic in Melbourne (Monheit, WC3333).
Seroconversion studies
TO determine the rate of new infections a number of longitudinal surveys of HIV seroconversion were undertaken. In such a study in the Friuli Venezia-Giulia region of Italy, 27% of the sample of 300 were initially seropositive, and 3 out of 84 (2.18 per 100 person-years) initially seronegative subjects who could be followed up seroconverted in an average of 20 months of follow up between 1986 and 1990 (Majori, WC3335). In Barcelona, Spain, 898 out of 1,328 subjects were initially seropositive, and 41 out of 131
440 FLORENCE SUMMARIES:A. DURANTE subjects who could be followed up seroconverted in an average of 15 months of follow up between 1984 and 1990 (Jacas, WC3329). Stimson (TUC54) reported a prevalence of 1.2% in a sample of exchange scheme attenders and 3.6% in a sample of non-attenders in the same areas in England in mid 1989 and found no seroconversions in the 54% of subjects followed up in mid 1990. In Lund, Sweden none of the 200 injecting drug users followed for the last 4 years had seroconverted (Ljungberg, WC3290). Unfortunately, these three surveys may be too small to estimate the seroconversion rate reliably. In a much larger cohort of drug users (n = 2,234) recruited between 1988 and 1989 to the Alive survey in the United States, there were 25 seroconversions per 100 person years in female users and 63 in men (Kenard, THC102).
Behaviour A large number of surveys reported an increase in the level of safer injection practices (injection with new or cleaned needles and syringes), including Stimson (THC45) in England, Neaigus (MD4057) and Battjes (THC46) in the United States and Seyrer (THC50) in the European Community. Vlahov (MC49) reported only a modest, statistically insignificant, protective effect of using bleach to disinfect syringes. The sample size of this survey was small (22 cases and 95 controls) and the effect of sexual activity on the seroconversion of the subjects studied does not seem to have been examined. Therefore, further research in this area is urgently needed to determine whether the effect of using bleach as a disinfectant is as limited as this study suggests. It was also widely reported that condom use remains low among many injecting drug users-Coyne (WC3292) in England, Gallagher in Massachusetts in USA (MD4099), Pomeroy (WC3314) in Dublin, Malinveri (WC3366) in Bern, Switzerland, Watkins in Pennsylvania, USA (WC3320). Kall (WC3352), who followed a cohort of ini-
tially negative drug users, found that while seroconversion in men was primarily attributed to injecting with contaminated syringes, seroconverion in women was primarily attributed to sex with an infected male sexual partner. This, she hypothesizes, is because as sharing diminishes, the risk of sexual transmission would increase and first be seen in women because of the more efficient transmission of HIV from men to women.
Type of drug injected An important clarification in the relationship between HIV transmission and injecting drug use came from Klee (TUD106) who observed that amphetamine sulphate users in the North West of England differed from heroin users not only in their injecting but also their sexual behaviour. Amphetamine users had a higher frequency of sexual intercourse, had more casual sexual partners (especially those under 20) and were more likely to inject in a group. A number of studies in the United States also examined the relationship between the drug injected and HIV risk. Anderson (WC3308) in California found that stimulant users had significantly higher rates of infection (5% vs 1%), unsafe sex and injecting behaviour than opiate users. Harris (WC3363) also in California, found that amphetamine use unlike race, sharing levels, prostitution, use of exchange schemes and age, was associated with HIV infection (OR = 4.1, 95% CI 1.6-10.4). Irwin (THC49) reported that 113 of the crack users she studied started to inject heroin after beginning to use crack to balance the effects of crack. This is an area which requires further study.
Prison For many years it has been known that prisons could play an important role in the transmission of HIV, not only because injecting drug users who continue to inject in prison do not have access to clean syringes
HIV INFECTION IN INJECTING DRUG USERS
and bleach, but also because of the random mixing effect of prison. Prison brings together injectors who would not ordinarily inject as a group and therefore allows the spread of HIV between geographically and socially distinct groups. This effect is thought to have been important in the rapid transmission of HIV in Bangkok (Choopanya, MD4056). A number of surveys presented at the conference documented the role of prisons in the transmission of HIV. Dolan studied a sample released from prison in the last 3 months, 28% of which continued to inject in prison. Sixty-three percent of them shared syringes in prison. Within this sample, there was a 15.5% HIV prevalence in the female injectors and 7.7% in the male injectors (WC3321). Bley (WC3362) found that a sample of prison inmates had a prevalence rate 2.4 times higher than a sample of exchange scheme clients and 7.2 times higher than a sample from a drug treatment clinic. Abeni (WC3332) reported that those who were in prison were more likely to be HIV positive than those who were not imprisoned. Progression Mariatto (MC3130), Rezza (MC45) and Margolick (TUC44) reported that age is directly related to the speed of progression. Margolick (TUC44) also reported that continued use of heroin did not increase the rate of progression in a longitudinal survey,
441
whereas the Toxicomania Operative Group (MC3180) found that those who no longer injected did have a slower progression. This is an area which requires further study, because it will have a direct effect on the treatment of HIV positive injecting drug users.
Conclusion The prevalence surveys reported here show that HIV infection in injecting drug users is present in varying levels, worldwide. It appears that safer injecting may now be a cultural norm among injecting drug users although this does not seem to be the case with safer sexual practices. Prison is one place where safer injecting is not possible and this will have serious implications for HIV transmission within and beyond prisons. We must look beyond injecting drug use in a generic sense, to the relationship between particular types of drug used and transmission, if we are to accurately study the pattern of HIV transmission in injecting drug users. More research is needed on the interaction between continued drug use and HIV progression. After 10 years, the nature of the findings of epidemiological research on AIDS may be changing. The time of rapid advances may now be over, replaced by slower, more incremental, although ultimately no less important, progress in the study of HIV disease in injecting drug users.
AIDS CARE, VOL. 3, NO. 4, 1991
HIV infection in injecting drug users A. DURANTE Public Health Laboratory Service, 61 Colindale Avenue, London NW9 SEQ, UK
Introduction There were no great surprises in the field of HIV epidemiology in injecting drug users at the Seventh International Conference on AIDS in Florence this year. Instead, the research findings presented tended to clarify and broaden our understanding of the concepts already existing in the field. Some gaps in the picture of worldwide HIV prevalence and infection rates were filled. The potential for the spread of HIV in prisons was documented. Behaviour patterns associated with transmission were further examined and quantified. The progression of HIV was observed. Prevalence studies To determine the extent of HIV infection in injecting drug users, prevalence surveys have been undertaken throughout the world. Haw (WC3049) reported a prevalence of 1.5% in 500 injecting drug users in and out of treatment in Glasgow. A 1.2% prevalence was found by Durante (WC3343) between December 1989 and March 1991 from a sample of 1,868 injecting drug users attending a variety of drug services in England and Wales. Crosier (MC48) reported a prevalence of 13% from a sample of 534 injecting drug users recruited from within treatment and outside treatment in London. The Crosier and Haw surveys were part of the European Community serial point preva-
lence survey which presented its first year’s results at this conference. In this survey, Spain reported the highest prevalence at 50% and Greece the lowest at 2% (Seyrer, THCSO). After a rapid increase between 1987 and 1988, the prevalence in Bangkok seems to have become stable at around 32-44% (Choopanya, Community Responses to AIDS, Parallel Session). The Soviet Union reports having found no cases of HIV among injecting drug users to date (Sauchenko, WC3365). A prevalence of 57% was found among IDUs in the state of Sao Paul0 in Brazil in 1990 (Mesquita, MC3008). A rate of 2% prevalence was found in injecting drug users in a methadone treatment clinic in Melbourne (Monheit, WC3333).
Seroconversion studies
TO determine the rate of new infections a number of longitudinal surveys of HIV seroconversion were undertaken. In such a study in the Friuli Venezia-Giulia region of Italy, 27% of the sample of 300 were initially seropositive, and 3 out of 84 (2.18 per 100 person-years) initially seronegative subjects who could be followed up seroconverted in an average of 20 months of follow up between 1986 and 1990 (Majori, WC3335). In Barcelona, Spain, 898 out of 1,328 subjects were initially seropositive, and 41 out of 131
440 FLORENCE SUMMARIES:A. DURANTE subjects who could be followed up seroconverted in an average of 15 months of follow up between 1984 and 1990 (Jacas, WC3329). Stimson (TUC54) reported a prevalence of 1.2% in a sample of exchange scheme attenders and 3.6% in a sample of non-attenders in the same areas in England in mid 1989 and found no seroconversions in the 54% of subjects followed up in mid 1990. In Lund, Sweden none of the 200 injecting drug users followed for the last 4 years had seroconverted (Ljungberg, WC3290). Unfortunately, these three surveys may be too small to estimate the seroconversion rate reliably. In a much larger cohort of drug users (n = 2,234) recruited between 1988 and 1989 to the Alive survey in the United States, there were 25 seroconversions per 100 person years in female users and 63 in men (Kenard, THC102).
Behaviour A large number of surveys reported an increase in the level of safer injection practices (injection with new or cleaned needles and syringes), including Stimson (THC45) in England, Neaigus (MD4057) and Battjes (THC46) in the United States and Seyrer (THC50) in the European Community. Vlahov (MC49) reported only a modest, statistically insignificant, protective effect of using bleach to disinfect syringes. The sample size of this survey was small (22 cases and 95 controls) and the effect of sexual activity on the seroconversion of the subjects studied does not seem to have been examined. Therefore, further research in this area is urgently needed to determine whether the effect of using bleach as a disinfectant is as limited as this study suggests. It was also widely reported that condom use remains low among many injecting drug users-Coyne (WC3292) in England, Gallagher in Massachusetts in USA (MD4099), Pomeroy (WC3314) in Dublin, Malinveri (WC3366) in Bern, Switzerland, Watkins in Pennsylvania, USA (WC3320). Kall (WC3352), who followed a cohort of ini-
tially negative drug users, found that while seroconversion in men was primarily attributed to injecting with contaminated syringes, seroconverion in women was primarily attributed to sex with an infected male sexual partner. This, she hypothesizes, is because as sharing diminishes, the risk of sexual transmission would increase and first be seen in women because of the more efficient transmission of HIV from men to women.
Type of drug injected An important clarification in the relationship between HIV transmission and injecting drug use came from Klee (TUD106) who observed that amphetamine sulphate users in the North West of England differed from heroin users not only in their injecting but also their sexual behaviour. Amphetamine users had a higher frequency of sexual intercourse, had more casual sexual partners (especially those under 20) and were more likely to inject in a group. A number of studies in the United States also examined the relationship between the drug injected and HIV risk. Anderson (WC3308) in California found that stimulant users had significantly higher rates of infection (5% vs 1%), unsafe sex and injecting behaviour than opiate users. Harris (WC3363) also in California, found that amphetamine use unlike race, sharing levels, prostitution, use of exchange schemes and age, was associated with HIV infection (OR = 4.1, 95% CI 1.6-10.4). Irwin (THC49) reported that 113 of the crack users she studied started to inject heroin after beginning to use crack to balance the effects of crack. This is an area which requires further study.
Prison For many years it has been known that prisons could play an important role in the transmission of HIV, not only because injecting drug users who continue to inject in prison do not have access to clean syringes
HIV INFECTION IN INJECTING DRUG USERS
and bleach, but also because of the random mixing effect of prison. Prison brings together injectors who would not ordinarily inject as a group and therefore allows the spread of HIV between geographically and socially distinct groups. This effect is thought to have been important in the rapid transmission of HIV in Bangkok (Choopanya, MD4056). A number of surveys presented at the conference documented the role of prisons in the transmission of HIV. Dolan studied a sample released from prison in the last 3 months, 28% of which continued to inject in prison. Sixty-three percent of them shared syringes in prison. Within this sample, there was a 15.5% HIV prevalence in the female injectors and 7.7% in the male injectors (WC3321). Bley (WC3362) found that a sample of prison inmates had a prevalence rate 2.4 times higher than a sample of exchange scheme clients and 7.2 times higher than a sample from a drug treatment clinic. Abeni (WC3332) reported that those who were in prison were more likely to be HIV positive than those who were not imprisoned. Progression Mariatto (MC3130), Rezza (MC45) and Margolick (TUC44) reported that age is directly related to the speed of progression. Margolick (TUC44) also reported that continued use of heroin did not increase the rate of progression in a longitudinal survey,
441
whereas the Toxicomania Operative Group (MC3180) found that those who no longer injected did have a slower progression. This is an area which requires further study, because it will have a direct effect on the treatment of HIV positive injecting drug users.
Conclusion The prevalence surveys reported here show that HIV infection in injecting drug users is present in varying levels, worldwide. It appears that safer injecting may now be a cultural norm among injecting drug users although this does not seem to be the case with safer sexual practices. Prison is one place where safer injecting is not possible and this will have serious implications for HIV transmission within and beyond prisons. We must look beyond injecting drug use in a generic sense, to the relationship between particular types of drug used and transmission, if we are to accurately study the pattern of HIV transmission in injecting drug users. More research is needed on the interaction between continued drug use and HIV progression. After 10 years, the nature of the findings of epidemiological research on AIDS may be changing. The time of rapid advances may now be over, replaced by slower, more incremental, although ultimately no less important, progress in the study of HIV disease in injecting drug users.
