The acquired immunodeficiency syndrome and intravenous drug abuse

Sections

ABSTRACT
Introduction
An overview of the AIDS epidemic
The extent of the HIV and intravenous drug abuse problem
The spread of HIV infection: intravenous drug abusers
The spread of HIV infection: sexual and perinatal transmission
Opportunities for prevention
The importance of drug abuse treatment
Treatment with methadone
Therapeutic community treatment
The retention of patients in treatment
The injection of drugs other than opiates
Outreach efforts
Treatment capacity
Other risk reduction strategies
Directions for research
Concluding remarks

Details

Author: R. J. BATTJES,, C. G. LEUKEFELD, , R. W. PICKENS , H. W. HAVERKOS
Pages: 21 to 34
Creation Date: 1988/01/01

The acquired immunodeficiency syndrome and intravenous drug abuse

R. J. BATTJES,
C. G. LEUKEFELD,
R. W. PICKENS
H. W. HAVERKOS
National Institute on Drug Abuse, Rockville, Maryland, United States of America

ABSTRACT

Intravenous drug abusers constitute 25 per cent of the cases of the acquired immunodeficiency syndrome (AIDS) in adults in the United States of America and 21 per cent of such cases in Europe. The potential for the rapid spread of the human immunodeficiency virus (HIV) among intravenous drug abusers exists because such drug abusers commonly share drug injection equipment. The heterosexual and perinatal spread of AIDS is also largely associated with intravenous drug abusers, and drug abusers have been identified as a major vector for the spread of the AIDS epidemic as it is associated with intravenous drug abuse. As long as intravenous drug abusers are addicted, they will continue to be at risk of contracting AIDS. Thus, the primary AIDS prevention strategy must be to help addicts to stop using drugs. It is suggested that drug abuse treatment resources should be expanded and outreach programmes developed to encourage more intravenous drug abusers to enter treatment. AIDS risk-reduction counselling must also be provided to intravenous drug abusers who continue injecting drugs, and to addicts and their sexual partners to prevent the sexual spread of HIV. Vigorous AIDS prevention initiatives must be undertaken now, using the most promising intervention strategies, while simultaneously evaluating and refining these strategies.

Introduction

AIDS is a major public health epidemic throughout the world. In Europe and the United States, AIDS is found primarily among homosexual and bisexual men. It is also a serious public health problem, however, among intravenous drug abusers, their sexual partners and children. Behavioural change is currently the primary means available to prevent the spread of AIDS. This article reviews the AIDS epidemic, specifically as it is associated with intravenous drug abuse, and suggests public health measures to combat the epidemic.

An overview of the AIDS epidemic

Since 1981 when the first cases were identified, the acquired immunodeficiency syndrome (AIDS) has spread at an alarming rate. As of 1 February 1988, 52,256 cases of AIDS in the United States had been reported to the Center for Disease Control, with 21,765 of these cases reported within the previous year alone. Of the 52,256 cases, 29,206 deaths had been reported [ 1] . AIDS is a world-wide epidemic. For example, as of 30 September 1987, the World Health Organization (WHO) had reported 8,508 cases of AIDS in Europe [ 2] and also cases in Africa, Asia, Latin America and Australia.

The extent of the AIDS epidemic is projected to continue to escalate for some years. In the United States, for example, the United States Public Health Service estimated in 1986 that between 1 million and 1 ,5 million Americans were infected with the human immunodeficiency virus (HIV), the virus that causes AIDS, and 20-30 per cent of these persons were expected to contract the disease by 1991. Thus, it is estimated that there will have been 270,000 cases of AIDS in the United States by 1991, with 179,000 deaths as of that date [ 3] . In the absence of an effective vaccine to prevent the spread of AIDS, the further spread of infection and disease beyond 1991 is expected. Since most individuals infected with the AIDS virus are asymptomatic and do not know that they are infected, the potential for the further spread of the disease is staggering.

The extent of the HIV and intravenous drug abuse problem

While the greatest number of AIDS cases occurs among homosexual and bisexual males, intravenous drug abusers compose the second largest group that has contracted AIDS. Twenty-five per cent of all cases of AIDS in adults in the United States have occurred among intravenous drug abusers. This includes 17 per cent of cases among heterosexual male and female intravenous drug abusers and 8 per cent of cases among homosexual and bisexual men who are also intravenous drug abusers. Thus, 12,735 of the AIDS cases reported by 1 February 1988 had occurred among intravenous drug abusers. Approximately 85 per cent of those cases were males (including 55 per cent heterosexual and 30 per cent homosexual/bisexual intravenous drug abusers), and 15 per cent were females [ 1] .

In Europe, heterosexual intravenous drug abusers constitute 18 per cent of the cases of AIDS in adults, and homosexual intravenous drug abusers constitute another 3 per cent. The spread of AIDS among intravenous drug abusers is an especially serious problem in southern Europe, with 62 per cent of the l,061 cases of AIDS in adults in Italy and 53 per cent of the 602 cases of AIDS in adults in Spain occurring among heterosexual intravenous drug abusers. Seventeen countries in Europe have reported one or more cases that are intravenous drug abusers [ 2] .

Until now, the cases of AIDS among intravenous drug abusers in the United States have been largely concentrated in New York (49 per cent of all adult intravenous drug abusers), New Jersey (12 per cent), and California (12 per cent), with lesser concentrations in Florida (5 per cent) and Texas (3 per cent). All 50 states, however, have reported one or more cases involving intravenous drug abusers [ 4] .

In the United States, blacks and Hispanics have been particularly hard hit by the AIDS epidemic, especially as it is associated with intravenous drug abuse. Blacks constitute 51 per cent of the cases of AIDS among heterosexual intravenous drug abusers, and Hispanics 30 per cent of these cases. Of the cases of AIDS among homosexual intravenous drug abusers, blacks constitute 22 per cent and Hispanics 14 per cent. The impact on minorities of AIDS associated with intravenous drug abuse is also reflected in the cases of AIDS among the heterosexual partners of intravenous drug abusers (85 per cent are black or Hispanic) and in the cases of perinatal AIDS among the offspring of intravenous drug abusers (91 per cent are black or Hispanic) [ 5] . Data show that drug abuse disproportionately affects minority groups [ 6-7] . The preponderance of blacks and Hispanics among intravenous drug abusers with AIDS is, at least in part, because of the over-representation of these ethnic groups among intravenous drug abusers. Whether other factors, such as differences in drug-use practices or general health status, also account for the high concentration of cases among ethnic minorities is not clear. The fact remains that AIDS associated with intravenous drug abuse largely affects blacks and Hispanics.

The spread of HIV infection: intravenous drug abusers

The current concentration of AIDS among intravenous drug abusers appears to be a time-related phenomenon. Once introduced, the infection can spread very rapidly. For example, an analysis of stored sera collected for a study of hepatitis B indicated that HIV was first introduced among intravenous drug abusers in New York City in 1978. By 1979, approximately 25 per cent of the addicts enrolled in that study were seropositive for HIV. More recent data collected to assess the extent of HIV infection among intravenous drug abusers indicated an infection rate of approximately 50 per cent in 1985, and an increase in the infection rate to approximately 60 per cent in the latter part of 1986 [ 8] . Similarly, studies in Edinburgh, Scotland, and Scotland as a whole showed that infection rates among intravenous drug abusers were approximately 50 per cent within two years of the first identified seropositive sample [ 9] .

A study made in New Jersey, United States, in 1984, demonstrated a marked difference in infection rates by geographic area. Among patients in methadone maintenance and detoxification programmes, 59 per cent of those living within 5 miles of New York City were seropositive, compared with 45 per cent, 24 per cent and 2 per cent of those living 3-9 miles, 10-25 miles and 100 miles, respectively, outside New York City [ 10] .

Prevalence data from other areas suggest very low rates of infection in many parts of the United States. For example, a rate of 1 per cent was found in New Orleans in 1984 [ 10] , 2 per cent in San Antonio, Texas, in 1986 [ 11] , 2 per cent in Los Angeles in 1986 [ 12] , and 6 per cent in Detroit in 1986 [ 13] . Yet, significantly higher infection rates are beginning to emerge in some areas. For example, in 1985, an HIV infection rate of 10 per cent was found among a sample of heterosexual intravenous drug abusers in San Francisco [ 14] . In

1986, infection rates of 29 per cent in Baltimore [ 15] and 24 per cent in New Bedford, Massachusetts [ 16] were found.

AIDS is spread among intravenous drug abusers primarily by the sharing of drug injection equipment that has been contaminated with HIV, and it can also be spread between these drug abusers by sexual contact. Intravenous drug abusers, according to their own reports, commonly share needles and syringes and seldom sterilize their shared injection equipment. For example, a study conducted in California in 1985 found that 80 per cent of the addicts reported sharing their needles [ 17] . In a study conducted between September 1983 and March 1985, 68 per cent of the addicts admitted to an in-patient drug abuse treatment programme in Dallas, Texas, reported sharing needles, and having shared them during 40 per cent of their drug-use episodes [ 18] . A study of intravenous drug abusers receiving drug abuse treatment in six areas of the United States (Baltimore, Denver, New York City, San Antonio, Tampa and southern California) found that the rates of needle-sharing ranged from 70 per cent in New York City to 99 per cent in San Antonio [ 15] . Among addicts in San Francisco who acknowledged sharing needles, only 19 per cent reported that they always sterilized their needles, while another 16 per cent reported that they usually sterilized their needles [ 14] . Thus, the potential for the rapid spread of HIV among intravenous drug abusers is considerable.

The spread of HIV infection: sexual and perinatal transmission

The United States Public Health Service has identified intravenous drug abusers as a major vector for the spread of AIDS to the general population [ 3] . AIDS has spread from intravenous drug abusers to their sexual partners and children. In the United States, of the cases of AIDS among persons who have had heterosexual contact with persons with AIDS or at risk of contracting AIDS, 69 per cent are individuals who have had sexual intercourse with intravenous drug abusers, compared with 15 per cent who have had intercourse with bisexual men [ 19] . Also, approximately three fourths of the cases of perinatal AIDS have occurred among the children of intravenous drug abusers [ 20] .

The number of cases of heterosexual and perinatal transmission has been small so far: 1,174 cases of heterosexual transmission and 603 perinatal cases as of 1 February 1988 [ 1] . The number of such cases, however, is also expected to increase substantially in future years. While the data on the ease of the heterosexual transmission of HIV are incomplete, there are indications that transmission may occur fairly readily, at least among the regular sexual partners of persons with AIDS. For example, a study of the spouses of AIDS patients found that 58 per cent of the 45 spouses who reported no other risk factor for AIDS were seropositive for HIV [ 21] . Twelve of 14 spouses who were initially seronegative and who continued to have sexual contact with their AIDS-diagnosed partners without using condoms became infected during the course of the study. It appeared that the virus was transmitted with equal ease from men to women and from women to men [ 21] . Similarly, in a study of the regular sexual partners of persons with AIDS or AIDS-related conditions, 48 per cent of 100 heterosexual partners with no other risk factors were infected, including 47 per cent of 88 female partners and 58 per cent of 12 male partners [ 22] . Data from Africa also support the importance of heterosexual transmission in the spread of AIDS and the bi-directional nature of that transmission [ 23] .

Many intravenous drug abusers are sexually active, and a substantial portion of female addicts and some male addicts resort to prostitution to support their drug habits. For example, a study of 184 opiate addicts in Baltimore found that 35 per cent of the females and 19 per cent of the males reported that they had engaged in prostitution, defined as having engaged in sex for money or drugs, during the five years previous to the study [ 11] . In a study of 835 female prostitutes in seven areas throughout the United States, half of the prostitutes had a history of intravenous drug abuse. While over 80 per cent of these prostitutes reported the use of a condom at least once, only 4 per cent reported the use of a condom with each vaginal exposure during the five years previous to the study [ 24] . Thus, the potential for the spread of AIDS to non-addicts is considerable, especially as HIV infection increases among intravenous drug abusers.

Opportunities for prevention

Based on limited research conducted in New York City, it appears that intravenous drug abusers are concerned about the risk of contracting AIDS and that some addicts are making efforts to reduce their risk. The reports of drug abusers and needle-sellers and observations of drug sales indicate an increased demand for sterile needles [ 25, 26] . More recently, in New York City, 137 intravenous drug users not in treatment were interviewed informally regarding behavioural change in response to AIDS. Three fourths of those interviewed knew that the spread of AIDS was related to intravenous drug use, two fifths reported that they had made some change in drug-use practices to protect themselves, and one fifth reported that they had made changes in their sexual behaviour [ 27] .

The fact that some intravenous drug abusers are concerned about their risk of contracting AIDS and are making efforts to change their behaviour is an indication that there are opportunities to prevent the spread of AIDS in this group of the population. It is also apparent, however, that high-risk behaviour continues at a substantial rate. Concerted efforts to motivate and assist intravenous drug abusers to change their high-risk behaviour is clearly necessary.

The importance of drug abuse treatment

Intravenous drug abusers are at risk of becoming infected with HIV through needle-sharing. Thus, the primary AIDS-prevention strategy with this population group must be to help it to stop using drugs. Drug abuse treatment is effective in reducing illicit opiate use and can be expected to reduce the transmission of AIDS among intravenous drug abusers. Two treatment modalities, methadone treatment and therapeutic community treatment, are the most widely used in the United States and provide the clearest evidence of the effectiveness of treatment.

Treatment with methadone

Intravenous drug abusers experience immediate and dramatic reductions in drug use following enrolment in methadone treatment and these reductions continue throughout treatment. A number of studies have illustrated these reductions, with an average of 75 per cent of patients using no illicit opiates while in treatment [ 28-30] . A large-scale study of 44,000 addicts enrolled in 52 treatment programmes found that the average use of opiates by patients in methadone treatment was reduced from 30 days per month to 1-2 days per month [ 31] . The longer addicts remained in methadone treatment, the more effective it was in reducing illicit opiate use. In one recent study, opiate drug use decreased from 100 per cent of addicts entering treatment to 23 per cent of those in treatment for one to four years and 8 per cent of those in treatment for five or more years [ 32] .

When administered on a daily basis, methadone allows addicts to function normally without fear of experiencing opiate-withdrawal symptoms. Most importantly, it eliminates the need to inject drugs intravenously. Methadone frees addicts from an extensive preoccupation with obtaining heroin each day, allowing them to focus their attention on family, work and other constructive activities. Opiate addiction is a chronic disorder. Thus, addicts need to be maintained on methadone until more normal living patterns have been established. In some cases, addicts can be gradually withdrawn from methadone after several months to lead drug-free lives. More typically, addicts must be maintained on methadone for longer periods, and some require prolonged treatment. Some addicts have been maintained on methadone for 10 years or longer. There is no evidence that long-term methadone maintenance has adverse medical consequences and it continues to be effective in reducing the use of heroin while it is administered [ 33] .

In methadone treatment, a favourable outcome depends largely on the ability of programmes to retain patients until they have satisfactorily completed treatment. For patients who drop out of treatment prematurely, most eventually relapse to opiate use [ 34-36] . The rates of abstinence following treatment, however, are high for those patients who satisfactorily complete treatment. For example, in a study that followed heroin addicts for as long as six years after methadone treatment, 83 per cent of those who terminated with staff approval (i.e. who met discharge criteria) were opiate-free, compared with only 21 per cent of those who terminated prematurely or 13 per cent of those who were arrested [ 34] .

Therapeutic community treatment

While methadone treatment is the most widely used method of treatment for opiate addiction in the United States, therapeutic community (i.e. structured long-term residential) treatment is also commonly used. Like methadone treatment, therapeutic community treatment also results in substantial reductions in opiate use. In one large-scale study of drug abusers, daily opiate use was reduced to 39 per cent during a one-year post-treatment follow-up [ 37] . In another large-scale study of drug abusers who used opiates weekly or more frequently prior to treatment, 54 per cent reported no opiate use and 19 per cent reported less use in the year following treatment [ 38] . As with methadone treatment, a favourable outcome using therapeutic community treatment depends on the ability to retain patients in treatment. One study found that less than 5 per cent of those who had completed the programme reported any opiate use during a five-year follow-up period [ 39] . In another study of addicts who used opiates daily prior to treatment, only 29 per cent of those who remained in treatment for longer than 90 days used opiates daily following treatment, compared with 52 per cent of those who were in treatment for less than 90 days [ 37] .

The research studies cited above demonstrate that methadone and therapeutic community treatment have a positive impact not only on reducing illicit opiate use, but also on reducing the use of other drugs, increasing employment, improving psychological adjustment and decreasing criminality.

The retention of patients in treatment

While methadone and therapeutic community treatment are effective for those who complete treatment, the retention of patients in treatment is a significant problem. A high percentage of intravenous drug abusers drop out of treatment prematurely [ 34] [ 40] . The problem of retention reflects the chronic and severe nature of drug dependence. While the rate of drop-out from treatment is a concern, many of those who drop out subsequently return to treatment. The prevailing pattern for intravenous drug abusers is to have multiple treatment experiences before finally becoming abstinent from their principal drug of abuse [ 41] .

The injection of drugs other than opiates

Until recently, the injection of illicit drugs in the United States was limited primarily to heroin and other opiate addicts, many of whom injected cocaine as well. The injection of drugs by non-opiate drug abusers involved few persons and received little systematic study. The intravenous use of cocaine among nonopiate drug abusers has recently emerged as a significant problem, however, and research is beginning to address questions related to the effectiveness of drug-abuse treatment for this group of the population, For example, several research studies have indicated that desipramine may be effective in the treatment of cocaine abusers. In one study, the use of cocaine among abusers treated with desipramine was reduced by over 95 per cent, compared with 40 per cent among those receiving alternative treatments [ 42] .

Outreach efforts

While drug-abuse treatment is an important means of helping addicts to stop using drugs, only a small proportion of intravenous drug abusers (generally estimated at 10 to 20 per cent) are in treatment at any time. Thus, outreach efforts to encourage intravenous drug abusers to enter treatment-and to help them locate appropriate treatment must be a central strategy of efforts to prevent the spread of AIDS.

The challenge is to get more intravenous drug abusers to enter drug-abuse treatment and to keep them there. It is important to recognize that intravenous drug abusers are a difficult group to reach. They consist primarily of heroin addicts. As a group, these individuals are poorly educated, distrustful of authority and have a high rate of mental disorders and criminality [ 43-44] . As a result, addicts often seek anonymity. Thus, outreach efforts should extend into "copping" areas, the areas where addicts congregate to purchase and use drugs, and should incorporate indigenous ex-addicts who have credibility with this target group. In addition, outreach efforts should use other community agencies to make contact with intravenous drug abusers, for example, emergency rooms, jails and social service agencies.

Innovative methods need to be developed to encourage intravenous drug abusers to enter treatment. The New Jersey Department of Health, United States, is testing one outreach approach whereby street outreach workers talk with addicts about AIDS and give them vouchers that can be redeemed for free drug detoxification treatment. Preliminary data suggest that this approach has been successful in attracting intravenous drug abusers into treatment, especially those who have not previously been in treatment [ 45] . Other innovative recruitment strategies, such as the use of mobile treatment vans, must also be considered.

Treatment capacity

The lack of an adequate capacity for treatment is also a serious problem. Many treatment programmes in the United States are full and have waiting lists. Some programmes have exceeded their capacity, with the result that the quality of the treatment suffers. If additional intravenous drug abusers are to be recruited, treatment capacity must be expanded substantially and new programmes established. In addition, new approaches to treatment are needed (not simply more of the same approaches), if programmes are to respond effectively to the diverse needs of an expanded population needing treatment. For example, the injection of cocaine by patients in methadone maintenance treatment is a serious problem that treatment programmes must address. The expansion of existing, and the development of new, drug-abuse treatment resources, however, will require more than additional funding. A major obstacle to the expansion of treatment is the location of facilities acceptable to the community, since local neighbourhoods frequently object to the location of drug treatment programmes in their area.

Other risk reduction strategies

Not all intravenous drug abusers can be induced to enter treatment, and some individuals in treatment will continue to inject drugs. Thus, outreach efforts also must be initiated to inform intravenous drug abusers about the transmission of HIV, advising them not to share injection equipment and providing specific instructions on how equipment should be cleaned in order to reduce the likelihood of HIV transmission. For example, the Mid-City Consortium to Combat AIDS in San Francisco, United States, has placed community health outreach workers in areas where intravenous drug abusers are concentrated. These workers provide addicts with one-ounce bottles of bleach and instructions on how to clean their needles and syringes. Preliminary data indicate that addicts know that bleach can be used to clean injection equipment, and approximately two thirds of them are using bleach at least part of the time [ 46] . Bleach has been demonstrated to inactivate HIV in the laboratory [ 47] , but its efficacy as used by addicts has yet to be established. Since a significant number of intravenous drug abusers who enter treatment continue to use drugs occasionally or subsequently relapse into intravenous drug abuse, intravenous drug abusers in treatment must also be informed about the transmission of HIV and effective methods of cleaning needles.

In some European countries, including the Netherlands and the United Kingdom of Great Britain and Northern Ireland, needle-exchange programmes have been initiated in which intravenous drug abusers can obtain sterile needles and syringes in exchange for used ones. It is still too early to assess fully the impact of these efforts on needle-sharing among intravenous drug abusers. Preliminary data from the Netherlands, however, suggest that the programme is used by addicts, and that it does decrease needle-sharing behaviour, does not initiate individuals into intravenous use, and does not decrease the willingness of addicts to enter treatment [ 48] .

In addition to needle-sharing as a means of transmitting HIV, two other modes of transmission are of concern: sexual transmission from intravenous drug abusers to their sexual partners, and perinatal transmission from intravenous drug abusers and their sexual partners to their offspring. Intravenous drug abusers, both in and out of treatment, must be informed of the dangers of transmitting HIV to their sexual partners and offspring, and also of becoming infected with HIV by sexual contact with other intravenous drug abusers. Information on ways of reducing the risk of sexual transmission, including information on the use of condoms, should be provided through outreach efforts and programmes focused on patients in drug-abuse treatment. Special outreach efforts are needed in connection with drug-abusing prostitutes, given their potential for spreading AIDS to large numbers of people.

Informing intravenous drug abusers of the risks they run is not a reliable way of getting information on AIDS to their sexual partners: prevention efforts must also be aimed at these individuals directly. Drug-abuse treatment programmes provide one resource for educating sexual partners. These programmes have ready access to only a small proportion of sexual partners, however. Outreach efforts directed to sexual partners are needed. Changes in the sexual behaviour of intravenous drug abusers and their sexual partners will not be achieved easily. For example, one research team found that it is more difficult to get male intravenous drug abusers to use condoms than it is to get them to use bleach for cleaning needles [ 46] .

Since infected individuals can unknowingly transmit HIV to others, antibody testing for HIV and counselling should be made widely available to intravenous drug abusers and their sexual partners. Infected individuals knowledgeable about their test results can assume responsibility for protecting others from infection, Testing, coupled with appropriate counselling, provides an excellent opportunity to inform and educate these individuals about risks and the procedures to protect themselves and others from infection, Testing must be voluntary, however, since mandatory testing would make the addiction subculture even more covert than it is and would discourage intravenous drug abusers from seeking treatment.

Directions for research

Ideally, research to determine effective prevention strategies should precede the widespread implementation of programmes. Given the gravity of the AIDS epidemic, however, programme implementation cannot await research results. The programmatic strategies described above must be pursued vigorously.

Concurrent research is needed to improve the effectiveness of future prevention and education efforts. Priorities for research should include efforts to improve the recruitment of intravenous drug abusers into treatment programmes and to enhance the effectiveness of drug abuse treatment, including the development of new and more effective behaviour therapies, psychotherapies, and pharmacotherapies. Buprenorphine, which has both opiate agonist and antagonist properties, appears especially promising in the treatment of opiate addiction, and research on this pharmacological agent should be a priority. Research on other strategies for behavioural change, including the adoption of needle-cleaning and safer sexual practices, should also be a priority. Research on the interrelationship between knowledge, attitudes and behavioural change is also needed.

Another area of research is the availability of sterile drug-injection equipment. Research in this area is being carried out in the Netherlands and the United Kingdom. In the United States, support for this area of research has come from the Committee on a National Strategy for AIDS of the Institute of Medicine and the National Academy of Sciences, which recommended that: "Efforts to reduce sharing of injection equipment should include experimenting with removing legal barriers to the sale and possession of sterile, disposable needles and syringes" [ 49] . Participants at a recent conference on needle-sharing among intravenous drug abusers, held by the National Institute on Drug Abuse, recommended that research should be conducted to determine the effectiveness of small-scale needle-exchange programmes in the United States [ 50] . While advocates point out that the urgency of the AIDS epidemic requires action, opponents to such programmes are concerned that the greater availability of needles may facilitate the initiation of intravenous drug use.

Given the uncertainty of the impact of the programmes, any efforts to provide drug abusers with sterile needles should be undertaken on a pilot basis, with a careful evaluation of the effects of the programme on drug use and needle-sharing.

Another approach to the prevention of needle-sharing is the development of single-use, self-occluding needles and syringes. The widespread use of such injection equipment in medical practice might reduce the possibility of needle-sharing. The use of self-occluding needles in needle-exchange programmes would prevent the sharing of dispensed needles.

In addition to research focused on behavioural change, additional epidemiological research on intravenous drug abuse is needed to project the future spread of HIV infection in this group of the population. Information related to the characteristics and practices of intravenous drug abusers is based primarily on addicts who come into contact with the treatment system for drug abuse. Information on occasional intravenous drug abusers and those who abuse non-opiate drugs, such as amphetamines and cocaine, is especially sketchy. Obtaining more complete information regarding intravenous drug abusers should be a high priority.

Research is also needed to further the understanding of AIDS and its associated conditions that are related to intravenous drug abuse and to monitor changes in the epidemic over time. Because of the long latency period between infection and disease manifestation (often five or more years), monitoring the infection rates among intravenous drug abusers, their sexual partners and children in various parts of the world is very important. This information is needed in order to target prevention efforts and to plan for the future healthcare needs of persons with AIDS. Research is also needed to clarify the natural history of AIDS and co-factors that contribute to infection and the progression of the disease. Considering the large numbers of intravenous drug abusers who are already infected with the AIDS virus, it is important to determine factors that may delay or prevent progression to clinical AIDS. Included in this latter area is research to determine the effects of both therapeutic drugs and drugs of abuse, including tobacco and alcohol, on the immune system.

Concluding remarks

Based on the spread of AIDS among intravenous drug abusers to date, a greatly expanded AIDS epidemic in this group of the population, and consequently in the heterosexual community as a whole, is a certainty unless concerted efforts are undertaken to prevent the spread of the disease among intravenous drug abusers. Many intravenous drug abusers know about AIDS and are making some efforts to alter their behaviour. However, intravenous drug abusers and their sexual partners need considerable help to modify more consistently and effectively their own risky behaviour. Appropriate behavioural change programmes must be mobilized immediately on a massive scale. The primary strategy must be to help intravenous drug abusers to stop using drugs by providing drug-abuse treatment. Outreach efforts should encourage intravenous drug abusers to stop injecting drugs, to stop sharing injection equipment if the use of intravenous drugs continues, and to sterilize injection equipment if needle-sharing continues. Outreach efforts to both intravenous drug abusers and their sexual partners must focus on behavioural change to protect against sexual and perinatal transmission. While vigorously proceeding with these efforts to reduce the spread of AIDS, research must also be conducted to enhance the efficacy of these efforts and to increase knowledge on the extent and nature of the AIDS epidemic related to intravenous drug abuse.

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