Less than half of the children born to mothers with opioid
dependency and hepatitis C were tested for hepatitis C between 2006 and 2015 in
a large clinic providing antenatal care for women with opioid use disorder, a
US study published in The Journal of Pediatrics has shown.
Hepatitis C can be transmitted from mother to infant in the
womb or at the time of delivery but is not transmitted through breastfeeding.
The rate of hepatitis C virus (HCV) transmission from mother to infant is lower
than the risk of vertical HIV transmission. A
meta-analysis of published studies found that the risk of transmission to
infants was 5.8% if the mother had untreated HCV monoinfection and 10.8% if the
mother had hepatitis C and HIV co-infection.
Testing the infants of women with hepatitis C should take
place after birth to determine if they already have the infection.
The American Academy of Pediatrics recommends that testing
of infants born to mothers with hepatitis C should either consist of two HCV RNA
tests, at least one month apart, or an HCV antibody test, 18 months after
birth. Antibody testing must be delayed until this time because infants carry
maternal antibodies until the age of 18 months.
However, infants may be missed if mothers are not engaged in
care prior to delivery, or if infants are not tested after delivery. To assess
how well services are doing at each stage in testing and engaging mothers and
infants in care, researchers look at what they call a cascade of care – the
proportion of people who progress from one step to the next, all the way to
diagnosis and treatment.
Women with opioid use disorders are at especially high risk
of HCV infection, and of transmitting HCV to their infants, especially if their
own infection is undiagnosed. As opioid use increases among younger people in
the United States, it is important for antenatal services to be aware of the
risk of HCV infection and of the need for maternal and infant HCV testing.
The rate of testing of infants is low in the United States;
a study in Philadelphia found that only 16% of likely exposed infants had been
tested for HCV antibodies by 20 months, and another study in Pittsburgh found
only 30% had been tested.
This review of the cascade of care investigated the
proportion of mothers with opioid use disorder tested for HCV antibodies, the
proportion of seropositive mothers who underwent nucleic acid testing for
chronic HCV infection, the proportion of infants born to mothers with HCV
infection who were tested for HCV and the proportion of those infants diagnosed
with HCV infection and linked to care.
The review included all women with an opioid use disorder
who gave birth between January 2006 and December 2015 at Boston Medical
Center’s RESPECT clinic, a multidisciplinary service for pregnant women with
opioid use disorders.
Women receiving care at the clinic were predominantly white
non-Hispanic (85% of seropositive women) and 95% were receiving opioid agonist
therapy, predominantly methadone. Urine screening showed that 26% of women with
HCV antibodies had used opioids within 30 days of delivery and 16% had used
cocaine.
Women with HCV were significantly more likely to be white
non-Hispanic, to smoke and to be receiving opioid agonist therapy (all p <
0.001).
Of 879 women who gave birth, 85% were tested for HCV
antibodies and 69% of those tested positive. Of women who tested positive, 72%
had an HCV RNA test to determine chronic infection status; of these, 71% (261)
had detectable HCV RNA. Of these women with chronic HCV infection, less than
half (107) were linked to care.
Linkage to care was significantly more likely among women
diagnosed in 2014 and 2015 compared to those diagnosed earlier (adjusted odds
ratio 2.2, 95% CI 1.4-4.7), suggesting that motivation to receive direct-acting
antiviral treatment (DAA) may have improved linkage to care, the authors say. Clinic
distance, use of illicit drugs, psychiatric diagnosis or HIV co-infection did
not affect the likelihood of linkage to care.
Looking at infants, 404 infants were born to
HCV-seropositive mothers. Of these, only 45% (180) had a complete diagnostic
follow-up to determine if they were HCV-free. Five out of 180 infants (2.8%)
were diagnosed with HCV.
Infant follow-up screening was nine times more likely to be
completed if the infant’s mother had co-infection with HIV (aOR 9.0, 95% CI
1.1-72.8). No other factor affected the likelihood of infant screening
completion in multivariable analysis.
The study authors note that guidelines on how to test for
HCV in infants have varied in the United States, and that simplified algorithms
for testing might improve screening rates. A single HCV RNA test, or an earlier
HCV antibody test, might improve diagnosis and retention in care, they suggest.
However, the benefits of early diagnosis for infants may be
limited until DAAs are studied in younger children. Due to
the small size of the population to date – the
American Liver Foundation estimates that between 23,000 and 46,000 children in
the United States have HCV – studies of DAA use in children have not been a
priority for manufacturers and no DAAS are currently licensed in the United
States for use in children below 12 years of age.