Current considerations of HIV and HCV testing and the risks of vertical transmission during pregnancy

Continued research, and insight provided by new epidemiological data, impact the recommendations and practice of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) testing during pregnancy. Without diagnosis and proper treatment, the risk of vertical transmission of HIV is as high as 25%,¹ and the odds of vertical HCV transmission are significantly higher for HIV-HCV−coinfected mothers.² An increase in the number of injection drug users, fueled in recent years by the prescription drug epidemic, is leading to an increase in HCV cases among women in the childbearing years.³ 

HIV testing to reduce the risk of vertical transmission

Pregnant women generally represent a low-prevalence population that undergoes HIV testing during prenatal care.¹ If prenatal HIV screening was not performed, or the prenatal screening results have been lost, the need exists to quickly re-test at the time of birth.¹ 

HIV screening in pregnant women remains important because of the alarming epidemiology of this disease. According to the Centers for Disease Control and Prevention (CDC), more than 1.1 million people in the United States are living with HIV infection, and almost one in six (15.8%) are unaware of their infection.⁴ Increased knowledge over the past decades about HIV has unfortunately not kept women out of harm’s way. By the end of 2010, one in four people living with HIV in the United States was an adult women or adolescent female age 13 and over.⁵ Black/African American and Hispanic/Latino women continue to be disproportionately affected by HIV.⁵

Women made up 20% (9,500) of the estimated 47,500 new HIV infections in the United States in 2010.⁵ Eighty-four percent of new HIV infections in women are from heterosexual contact.⁵ Only about half of the women diagnosed with HIV are getting the care they need, and only 4 in 10 have the virus under control.⁵ 

This is especially concerning because while the exact mechanism of mother-to-child transmission of HIV remains unknown, the greatest risk factor for vertical transmission is thought to be advanced maternal disease, likely due to a high maternal HIV viral load.⁶ Vertical transmission may also occur during intrauterine life, delivery, or breastfeeding.⁶

Unfortunately, about 30% of pregnant women are not even tested for HIV during pregnancy, and another 15% to 20% receive no or minimal prenatal care, thereby increasing the risk for potential newborn transmission.⁷ 

In 2011 the American Congress of Obstetricians and Gynecologists (ACOG) reaffirmed its recommendation for routine HIV screening for all pregnant women when they first present for prenatal care for each pregnancy.¹ ACOG notes that women should have the right to refuse testing after being informed that HIV testing will be drawn as part of their routine prenatal panel. This opt-out approach to prenatal screening, as advocated by the Institute of Medicine, is associated with higher testing rates among pregnant women.¹ However, several states have laws that prohibit this approach and mandate that patients sign consent forms and opt in for testing. A useful resource is The National HIV/AIDS Clinicians’ Consultation Center at the University of California-San Francisco, which maintains an online compendium of state HIV testing laws.⁸

HIV-HCV coinfection

HIV coinfection is one factor known to increase the risk of perinatal transmission of HCV.⁹ A meta-analysis reported that the rate of risk of vertical HCV transmission ranges from 4% to 10%, and that the odds of vertical HCV transmission are approximately 90% higher for women infected with HIV and HCV than for those infected with HCV alone.² Better understanding of the underlying biological mechanisms of HCV transmission in relation to HIV infection in both mothers and infants is needed and will be important in the development of effective public health measures to reduce vertical transmission of HCV to infants from HIV-HCV–coinfected mothers.² 

Worldwide, hepatitis B and C are the most common causes of chronic viral hepatitis in children and adults.¹⁰ The global prevalence of hepatitis C virus (HCV) infection is 2% to 3%, with 130 million to 170 million HCV-positive people, most of whom are chronically infected.¹¹ In industrialized nations, because of vaccination programs against hepatitis B, hepatitis C virus (HCV) has become the primary cause of chronic viral hepatitis in children,¹² with vertical transmission becoming the leading source of infection.^9,13-15 

In addition to HIV coinfection, higher maternal viral loads increase the risk of HCV perinatal transmission.⁹ The mechanisms of HCV vertical transmission are incompletely understood, and no effective preventive intervention strategies have been proven.⁹ The epidemiology of HCV varies among countries and the reported prevalence of HCV in pregnant women has not been extensively studied, due to the lack of preventative screening of infection and the lack of preventative measures of vertical transmission.¹⁶ 

CDC testing recommendations for chronic hepatitis C virus infection highlight the need to identify patient populations at risk. Millions of Americans have hepatitis C, but most don’t know it.¹⁷ People with hepatitis C often have no symptoms and can live with an infection for decades without feeling sick. As of 2007, deaths associated with HCV have surpassed deaths associated with HIV/AIDS in the U.S.¹⁸

The emerging HCV epidemic

It’s important to note, particularly with reference to the population of women of childbearing age, that the prescription drug crisis is leading to an increase of newly diagnosed HCV infection among people 15 to 30 years of age.³ The CDC reports rising rates of hepatitis C infection among young, primarily white injection drug users, both male and female, found in suburban and rural settings, who started prescription opioid use (e.g., oxycodone) before transitioning to heroin injection.³ This transition is fueled by the development of tolerance to prescription opioids, and the availability of higher-potency heroin at a cheaper cost in some locations.³ 

Forty-two of the 50 states report chronic HCV cases to CDC, and surveillance data plotting the geographic distribution of these incident cases of hepatitis C infection show that the cases follow the spine of the Appalachian Mountains, running from the Southeast through the eastern edge of the Midwest states, and ending in upstate New York and New England.³ 

While adults born between 1945 and 1965 are the only group recommended by the CDC to be tested once for HCV without prior ascertainment of HCV risk factors, it’s important to note that a test for HCV antibodies is recommended for routine testing of asymptomatic persons with specific risk factors, including those who have ever injected drugs (Table 1).¹⁹ For those with reactive test results, the anti-HCV test should be followed with an additional, supplemental or confirmatory test for presence of the virus.¹⁹

Over time, chronic hepatitis C can lead to liver damage, cirrhosis, liver cancer, and death.²⁰ Hepatitis C is the leading cause of liver transplants.²⁰ But successful treatments can eliminate the virus from the body and prevent liver damage, cirrhosis, and cancer.²⁰ 

Advancements in clinical and epidemiologic research continue to demonstrate the value of laboratory testing in pregnancy. Future research is needed to better understand the mechanisms of HIV and HCV perinatal transmission and identify the most effective prevention strategies. Following testing guidelines and treatment for HIV and HCV can improve the health of infected mothers and identify newborns potentially at risk of vertical transmission.

References

1. American College of Obstetrics and Gynecology, Committee on Obstetric Practice. Prenatal and perinatal human immunodeficiency virus testing: expanded recommendations. September 2008, reaffirmed 2011. No. 418. Obstet Gynecol. 2008;112:739-742. 
2. Polis C, Shah S, Johnson K, Gupta A. Impact of maternal HIV coinfection on the vertical transmission of hepatitis C virus: a meta-analysis. Clin Infect Dis. 2007;44(8):1123-1131.
3. U.S. Dept of Health and Human Services, Office of HIV/AIDS and Infectious Disease Policy: Hepatitis C Virus Infection in Young Persons Who Inject Drugs. May 29, 2013. http://aids.gov/pdf/hcv-and-young-pwid-consultation-report.pdf. Accessed July 8, 2014. 
4. Centers for Disease Control. HIV in the United States: At a Glance. November, 2013. http://www.cdc.gov/KnowMoreHepatitis/?s_cid=bb-dvh-yb-006. Accessed July 1, 2014. 
5. Centers for Disease Control. HIV among women. March 2014. http://www.cdc.gov/hiv/pdf/risk_women.pdf. Accessed July 1, 2014.  
6. Garcia PM, Kalish PA, Pitt J et al. Maternal levels of plasma HIV type 1 RNA and the risk of perinatal transmission. Women and Infants Study group. NEJM. 1999; 341(6):394-402. 
7. Rahangdale L, Cohan D. Rapid human immunodeficiency virus testing on labor and delivery. Obstet Gynecol. 2008;112(1):159-63. 
8. National HIV/AIDS Clinicians’ Consultation Center, UCSF Dept of Family and Community Medicine at San Francisco General Hospital. Perinatal HIV Hotline: 1-888-448-8765 www.nccc.ucsf.edu
9. Indolfi GI, Azzari C, Resti M. Perinatal transmission of hepatitis C virus. J Pediatrics. 2013; 163:6. 
10. Williams R. Global challenges in liver disease. Hepatology. 2006;44(3):521-526.
11. Baldo V, Baldovin T, Trivello R, Floreani A. Epidemiology of HCV infection. Curr Pharm Des. 2008; 14(17):1646-54.
12. Slowik MK, Jhaveri R. Hepatitis B and C viruses in infants and young children. Semin Pediatr Infect Dis. 2005; 16(4):296-305.
13. Bortolotti F, Resti M, Giacchino R, et al. Changing epidemiologic pattern of chronic hepatitis C virus infection in Italian children. J Pediatr. 1998;133(3):378-381.
14. Bortolotti F, Iorio R, Resti M, et al. An epidemiological survey of hepatitis C virus infection in Italian children in the decade 1990-1999. J Pediatr Gastroenterol Nutr. 2001; 32(5):562-566.
15. Bortolotti F, Iorio R, Resti M, et al. Epidemiological profile of 806 Italian children with hepatitis C virus infection over a 15- year period. J Hepatol. 2007; 46(5):783-790.
16. Floreani, A. Hepatitis C and pregnancy. World J Gastroenterol. 2013;19(40):6714-6720. 
17. Centers for Disease Control. Hepatitis C information on testing and diagnosis. Publication No. 220411. Oct, 2013. http://www.cdc.gov/hepatitis/hcv/pdfs/hepctesting-diagnosis.pdf. Accessed July 8, 2014. 
18. Ly K., Xing J., Klevens RM, Jiles RB, Ward JW, Holmberg, SD. The increasing burden of mortality from viral hepatitis in the United States between 1999 and 2007. Ann Intern Med. 2012;156(4) 271-278. 
19. Centers for Disease Control: Testing Recommendations for Chronic Hepatitis C Virus Infection. http://www.cdc.gov/hepatitis/HCV/GuidelinesC.htm. Accessed July 8, 2014. 
20. Centers for Disease Control: Know More Hepatitis. http://www.cdc.gov/KnowMoreHepatitis/?s_cid=bb-dvh-yb-006, Accessed July 8, 2014.