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Antonio L. Estrada, MSPH, Ph.D.
Professor and Head
Department of Mexican American Studies
University of Arizona
Presented At:
Making Connections
Preventing HIV, Hepatitis and Tuberculosis among
Substance-Using Populations
June 21, 2012
To highlight the epidemiology of HIV,
Hepatitis B (HBV), Hepatitis C (HCV) and TB
infection among substance-using populations.
To discuss risk factors and vectors for
transmission of these common pathogens
among substance-using populations.
To discuss treatment implications and
challenges with substance users who may be
co-infected or multiple-infected with these
pathogens.
Substance-using populations are those persons
who use illicit drugs like heroin, cocaine,
methamphetamine, etc. They can be injection
drug users (IDUs) or non-injection drug users
NIDUs).
World-wide, substance-using populations are an
important transmission bridge of blood-borne
pathogens like HIV, HBV, and HCV to others,
especially sexual partners and other substance
users.
TB is also very prevalent among substance-using
populations, as are socio-environmental factors
conducive to its transmission.
Substance-using populations may not be as
knowledgeable regarding HIV, HBV,HCV or
TB risks associated with indirect sharing of
injection and non-injection paraphernalia.
They also may not be aware of sexual
transmission risks related to HBV and/or
HCV.
Moreover, substance-using populations may
not be aware that they are infected with HIV,
HBV, HCV or TB which increases the risk for
transmission to others.
HIV infection among substance-using
populations varies with region, race/ethnicity,
and mode of drug ingestion:
Grimes et al. (2007) found a rate of 7% among 123
crack cocaine users who used at home in Houston,
TX;
Brassard et al. (2004) found a rate of 24% among 262
IDUs in Montreal.
Howard et al. (2002) found a rate of 32% among 806
heroin users in the Bronx, NY.
HIV/AIDS diagnoses among IDUs in the
U.S. and dependent areas:
During 1985–2009, the percentage of AIDS cases
attributed to injection drug use (IDU) ranged from
20% in 1985, to 32% in 1993 to 15% in 2009;
Although recent trends indicate a decline in the
proportion of newly diagnosed HIV infections
associated with injection drug use, drug-use
behaviors overall still account for 32% of new HIV
diagnoses.
Among Male IDUs*: Among Female IDUs:
50.4% were African 54.4% were African
American American
29.8% were 25.5% were non-
Hispanic/Latino Hispanic White
17.4% were non- 17.7% were
Hispanic White Hispanic/Latino
1.1% were Multiple 1.4% were Multiple
Races Races
< .06% for others < .06% for others
*In 2009, an estimated 4,172 diagnosed HIV infections were attributed to injection drug use
(IDU) in the 40 states and 5 U.S. dependent areas with confidential name-based HIV
infection reporting since at least January 2006.
HCV is endemic worldwide, with an
estimated prevalence of 3%.
HCV is the most common chronic blood-
borne pathogen in the U.S.; and is associated
with liver disease, liver cancer, and the
leading reason for liver transplantation.
It is estimated that 1.8% or 3.9 million persons
had been infected with HCV, of which 2.7
million have chronic infection (NHANES III).
Although the incidence of HCV is decreasing
in the U.S., the number of chronic HCV cases
is projected to peak in 2015.
Non-Hispanic African Hispanic Native
Hepatitis Overall
White American American American
Hepatitis
2.80 1.53 4.20 1.86 3.42
B
Hepatitis
0.60 0.56 0.73 0.38 3.61
C
Prevalence of Hepatitis C Virus (HCV) Infection by age
and Race/Ethnicity – United States, 1988- 1994,
NHANES III
Injection drug use currently accounts for most HCV
transmission in the United States and the world.
HCV infection is acquired more rapidly after initiation
of injection drug use than other viral infections
including HIV.
Several studies have shown rates from 70% to 90%
among IDUs who have injected for 5 years or longer.
However, more recent studies of new IDUs (< 2 years
injecting) indicate the prevalence of HCV has declined
from 53% in 1985-1995 to 38% in more recent years
(Hagan et al, 2008).
Scheinmann et al, (2007) in a recent meta-
analysis of 28 studies among non-injection drug
users (NIDUs) found that HCV rates varied
significantly:
From a low of 2.3% among intranasal cocaine users in
Brazil to a high of 35.3% among heroin and/or cocaine
NIDUs with a median of 14%.
One study reported that HBV positives were
significantly more likely than HBV negatives to be co-
infected with HCV.
Duration of NIDU was related to HBV prevalence.
Estimates of co-infected IDUs range from 50-90
percent.
In one recent study (Devi et al, 2005) serum samples
were tested from 250 IDUs in India with the following
results:
59.6% were HIV positive
90.4% were HCV positive
10.8% were HBV positive
6% were tri-infected (HIV, HCV, HBV)
4.8% were co-infected with HIV and HBV
52.4% were co-infected with HIV and HCV
Rates of HBV and HCV infection among young
IDUs are four times higher than rates of HIV
infection.
Duration of drug injection is the strongest
predictor of HBV and HCV infection. After 5
years of injecting, as many as 90% of IDUs are
infected with HBV and/or HCV.
Rates of HBV and HCV infection among drug
injectors is four times higher than rates reported
in the general population.
NIH estimates that 44% of those infected
with HCV are people of color. Given the co-
infection rates with HIV, this percent may be
higher among substance-using populations.
Similar to other blood-borne pathogens,
sexual transmission of HCV and HBV
appears to be more efficient from males to
females than from females to males.
A recent comprehensive review of illicit
substance use and TB shows some interesting
trends (Deiss, Rodwell, and Garfein, 2009):
Drug use is associated with a higher prevalence of
latent TB infection (LTBI), ranging from 10% to
59% depending on the type of drug user.
Drug use is also associated with a higher incidence
of TB disease.
However, in general, they found that IDUs and
non-IDUs do not differ in important ways related
to TB, suggesting they share a similar risk of LTBI.
Targeted tuberculin testing for Latent TB Infection
(LTBI) is essential for identifying persons who would
benefit by treatment if infected.
Persons infected with TB are at greatest risk for
developing disease within 1 year after infection
occurred.
Persons at highest risk for TB infection include the
homeless, those with HIV infection, and IDUs.
The incidence among HIV positive IDUs is 76/1,000
person-years compared to HIV negative/unknown
IDUs at 10/1,000 person-years.
One of the earliest studies conducted on the
relationship between TB and HIV infection
was Selwyn et al., 1989:
23% of HIV infected IDUs had a PPD.
20% of non-HIV infected IDUs had a PPD.
Rates of sero-conversion from a negative PPD to
a positive PPD was similar for HIV infection
and non-infected IDUs.
Active TB developed in 4% of the HIV positive
IDUs, most of whom had a prior positive PPD.
Reactivation of TB is a concern for HIV positive
IDUs.
Studies have shown that substance-using
populations:
Are more likely to be infectious;
Take longer to achieve a negative culture;
Are at increased risk for mortality;
Among HIV positive persons, TB has become a
major opportunistic infection primarily due to
the immunosuppression caused by HIV disease.
High Risk Groups for Hepatitis (From: Rawls &
Vega: J Clin Gastroenterol, Volume 39(2).February 2005.144-151):
Hepatitis A – international travel; MSM; injection
or non-injection drug use;
Hepatitis B – injection drug use or non-injection
drug use; MSM; persons with multiple sex
partners;
Hepatitis C – injection drug use or non-injection
drug use; persons with multiple sexual partners;
sexual contact with hepatitis C infected person.
Injection-Related/Syringe-Mediated Risk
Factors:
Duration of injection
Frequency of injection
Type of drug injected
Common drug purchases
Multi-person reuse of needle/syringe
Lack of proper bleaching
Sharing the drug cooker, cotton filter, or rinse
water
Front Loading (syringe-mediated drug dispersal)
Back Loading (syringe-mediated drug dispersal)
Sexual Risk Factors:
Sexual relations under the influence of drugs
Exchanging sex for money or drugs (survival sex)
Sexual bingeing (multiple sex partners over a short
period of time)
Multiple sex partners, especially concurrently
Unprotected sex with an infected individual
History of STIs, especially ulcerative
Male to female vs. female to male transmission
more efficient
Other Risk Factors:
Incarceration
Transfusion of blood and blood products, especially
prior to 1993
Solid organ transplantation from an infected person
Vertical transmission (mother to infant during birth)
History of intranasal cocaine use (HBV, HCV)
Sharing of crack pipe (HCV, HBV)
Sharing of contaminated personal care items (HBV,
HCV)
Tattooing, body piercing ( HBV, HCV)
Acupuncture with non-sterilized needles
Risk Factors for TB Transmission:
Cramped living spaces;
Poor ventilation;
Recent contact with infected person
“Shotgunning”, the practice of inhaling and then
exhaling smoke (e.g., crack cocaine, marijuana, etc.)
directly into another's mouth.
This practice has been reported among 17% and
62% of drug users and was implicated in a South
Dakota TB outbreak.
Several studies have documented the
hepatotoxicity of HIV treatment among HCV
co-infected patients.
Limited response rates have been noted,
especially for HCV genotypes 1 and 4 (<30%).
End-stage liver disease from HCV has
become a leading cause of death in co-
infected patients.
The immunologic response after the start of
HAART for HIV is less than in mono-infected
patients.
Risk of TB disease among substance users has been
shown to peak several years after they became infected
with HIV, in both the pre-HAART and the HAART
eras.
The time immediately after diagnosis of HIV infection
represents an opportunity for TB prevention and/or
treatment, but important barriers remain for the care
of TB among substance-using populations.
Early intervention in the injection drug use career can
significantly alter HBV and HCV incidence and
prevalence, and reduce the reservoir of infection
among substance-using populations.
However, drug-resistant TB is becoming a problem in
many parts of the U.S. and the world.
Behavioral interventions targeting risk factors
conducive to the spread of HIV, HBV, and HCV
among substance-using populations are needed.
Harm reduction programs like Syringe Exchange
Programs (SEPs) can dramatically alter the risk of
blood-borne infections among IDUs.
SEPs can facilitate access to health services and drug
treatment, but it is not a panacea.
Access to clinical trials must increase to examine
efficacy of treatment among substance-using
populations infected with HIV and HCV.
Health care utilization barriers (financial, institutional
and cultural) must be reduced or eliminated in order
to increase access for this marginalized population.
HCV infection among HIV infected substance
users is a major medical concern.
Many challenges exist in treating co-infected
substance-using populations:
Concurrent substance abuse, including alcohol
Co-morbid mental health conditions, which could
be exacerbated by HCV treatment
Low socio-economic status
Lifestyle resulting in poor medication adherence
Potential interactions and synergistic effects
between HIV antiretrovirals and anti-HCV
medications
Patient reluctance to try Interferon given its severe
side-effects (tolerability)
