Use of polymerase chain reaction and antibody tests in the diagnosis of vertically transmitted hepatitis C virus infection

CDC Recommendations for Hepatitis C Testing Among Perinatally Exposed Infants and Children - United States, 2023

The elimination of hepatitis C is a national priority (https://www.hhs.gov/sites/default/files/Viral-Hepatitis-National-Strategic-Plan-2021-2025.pdf). During 2010-2021, hepatitis C virus (HCV) acute and chronic infections (hereinafter referred to as HCV infections) increased in the United States, consequences of which include cirrhosis, liver cancer, and death. Rates of acute infections more than tripled among reproductive-aged persons during this time (from 0.8 to 2.5 per 100,000 population among persons aged 20-29 years and from 0.6 to 3.5 among persons aged 30-39 years). Because acute HCV infection can lead to chronic infection, this has resulted in increasing rates of HCV infections during pregnancy. Approximately 6%-7% of perinatally exposed (i.e., exposed during pregnancy or delivery) infants and children will acquire HCV infection. Curative direct-acting antiviral therapy is approved by the Food and Drug Administration for persons aged ≥3 years. However, many perinatally infected children are not tested or linked to care. In 2020, because of continued increases in HCV infections in the United States, CDC released universal screening recommendations for adults, which included recommendations for screening for pregnant persons during each pregnancy (Schillie S, Wester C, Osborne M, Wesolowski L, Ryerson AB. CDC recommendations for hepatitis C screening among adults-United States, 2020. MMWR Recomm Rep 2020;69[No. RR-2]:1-17). This report introduces four new CDC recommendations: 1) HCV testing of all perinatally exposed infants with a nucleic acid test (NAT) for detection of HCV RNA at age 2-6 months; 2) consultation with a health care provider with expertise in pediatric hepatitis C management for all infants and children with detectable HCV RNA; 3) perinatally exposed infants and children with an undetectable HCV RNA result at or after age 2 months do not require further follow-up unless clinically warranted; and 4) a NAT for HCV RNA is recommended for perinatally exposed infants and children aged 7-17 months who previously have not been tested, and a hepatitis C virus antibody (anti-HCV) test followed by a reflex NAT for HCV RNA (when anti-HCV is reactive) is recommended for perinatally exposed children aged ≥18 months who previously have not been tested. Proper identification of perinatally infected children, referral to care, and curative treatment are critical to achieving the goal of hepatitis C elimination.

Spontaneous Clearance of Vertically Acquired Hepatitis C Infection: Implications for Testing and Treatment

BACKGROUND

Current guidelines recommend that infants born to women with hepatitis C virus (HCV) viremia be screened for HCV antibody at age 18 months and, if positive, referred for RNA testing at 3 years to confirm chronic infection. This policy is based, in part, on analyses that suggest that 25%-40% of vertically acquired HCV infections clear spontaneously within 4-5 years.

METHODS

Data on 179 infants with HCV RNA and/or anti-HCV evidence of vertically acquired infection in 3 prospective European cohorts were investigated. Ages at clearance of infection were estimated taking account of interval censoring and delayed entry. We also investigated clearance in initially HCV RNA-negative infants in whom RNA was not detectable until after 6 weeks.

RESULTS

Clearance rates were initially high then declined slowly. Apparently, many infections clear before they can be confirmed. An estimated 65.9% (95% credible interval [CrI], 50.1-81.6) of confirmed infections cleared by 5 years, at a median 12.4 (CrI, 7.1-18.9) months. If treatment were to begin at age 6 months, 18 months, or 3 years, at least 59.0% (CrI, 42.0-76.9), 39.7% (CrI, 17.9-65.9), and 20.9% (CrI, 4.6-44.8) of those treated would clear without treatment. In 7 (6.6%) confirmed infections, RNA was not detectable until after 6 weeks and not until after 6 months in 2 (1.9%). However, all such cases subsequently cleared.

CONCLUSIONS

Most confirmed infection cleared by age 3 years. Treatment before age 3, if it was available, would avoid loss to follow-up but would result in substantial overtreatment.

Overall Vertical Transmission of Hepatitis C Virus, Transmission Net of Clearance, and Timing of Transmission

BACKGROUND

It is widely accepted that the risk of hepatitis C virus (HCV) vertical transmission (VT) is 5%-6% in monoinfected women, and that 25%-40% of HCV infection clears spontaneously within 5 years. However, there is no consensus on how VT rates should be estimated, and there is a lack of information on VT rates "net" of clearance.

METHODS

We reanalyzed data on 1749 children in 3 prospective cohorts to obtain coherent estimates of overall VT rate and VT rates net of clearance at different ages. Clearance rates were used to impute the proportion of uninfected children who had been infected and then cleared before testing negative. The proportion of transmission early in utero, late in utero, and at delivery was estimated from data on the proportion of HCV RNA positive within 3 days of birth, and differences between elective cesarean and nonelective cesarean deliveries.

RESULTS

Overall VT rates were 7.2% (95% credible interval [CrI], 5.6%-8.9%) in mothers who were human immunodeficiency virus (HIV) negative and 12.1% (95% CrI, 8.6%-16.8%) in HIV-coinfected women. The corresponding rates net of clearance at 5 years were 2.4% (95% CrI, 1.1%-4.1%), and 4.1% (95% CrI, 1.7%-7.3%). We estimated that 24.8% (95% CrI, 12.1%-40.8%) of infections occur early in utero, 66.0% (95% CrI, 42.5%-83.3%) later in utero, and 9.3% (95% CrI, 0.5%-30.6%) during delivery.

CONCLUSIONS

Overall VT rates are about 24% higher than previously assumed, but the risk of infection persisting beyond age 5 years is about 38% lower. The results can inform design of trials of interventions to prevent or treat pediatric HCV infection, and strategies to manage children exposed in utero.

Clinical practice guidelines for the management of children with mother-to-child transmitted hepatitis C virus infection

BACKGROUND

The first guidelines for care of pregnant women carrying the hepatitis C virus (HCV) and their infants were published in 2005 in Japan. Since then, evidence has gradually accumulated worldwide regarding the natural course and treatment of this condition and, especially in recent years, treatment for chronic hepatitis C in adult patients has made great progress. However, the clinical practice policy for children has not been standardized, and new clinical practice guidelines for children with mother-to-child (MTC) transmitted HCV infection have become necessary.

METHODS

In the development of the current guideline, we requested cooperation from The Japanese Society for Pediatric Infectious Diseases, The Japan Society of Hepatology, and the Japan Society of Obstetrics and Gynecology. The committee members were recommended and approved by each society to participate in developing the guidelines. The guideline was also created in accordance with the Minds Guide for Practice Guideline Development. The statements were prepared by consensus-building using the Delphi method, based on the comprehensively searched academic papers and guidelines. These articles were retrieved through searching the PubMed, Cochrane Library, and the Igaku Chuo Zasshi databases.

RESULTS

Eight clinical questions (CQs) with clinical statements were developed regarding etiology (CQs 1-3), diagnosis (CQs 4 and 5), and treatment (two CQs 6 and 7). In each statement, the consensus rate, evidence level, and recommendation level were determined.

CONCLUSION

The guidelines will be helpful in the management of children with hepatitis C MTC transmission.

Nucleic Acid Testing for Diagnosis of Perinatally Acquired Hepatitis C Virus Infection in Early Infancy

BACKGROUND

Most US children with perinatal hepatitis C virus (HCV) exposure fail to receive the recommended anti-HCV antibody test at age ≥18 months. Earlier testing for viral RNA might facilitate increased screening, but sensitivity of this approach has not been established. We hypothesized that modern HCV-RNA RT-PCR platforms would adequately detect infected infants.

METHODS

Nationwide Children's Hospital electronic health records from 1/1/2008 to 30/6/2018 were reviewed to identify perinatally exposed infants tested by HCV-RNA RT-PCR at age 2-6 months. Diagnostic performance was determined using a composite case definition: (1) infected children had positive repeat HCV-RNA testing or positive anti-HCV at age ≥24 months; (2) uninfected children lacked these criteria and had negative anti-HCV at age ≥18 months.

RESULTS

770 perinatally exposed infants underwent HCV-RNA testing at age 2-6 months. Of these, 28 (3.6%) tested positive; viremia was confirmed in all who underwent repeat testing (n = 27). Among 742 infants with negative HCV-RNA results, 226 received follow-up anti-HCV testing at age ≥18 months, of whom 223 tested negative. Three children had low-positive anti-HCV results at age 18-24 months that were negative upon retesting after age 24 months, possibly indicating waning maternal antibodies. Using the composite case definitions, early HCV-RNA screening demonstrated sensitivity of 100% (87.5-100%, Wilson-Brown 95% CI) and specificity of 100% (98.3-100%).

CONCLUSIONS

Modern HCV-RNA RT-PCR assays have excellent sensitivity for early diagnosis of perinatally acquired infection and could aid HCV surveillance given the substantial loss to follow-up at ≥18 months of age.

Hepatitis C Virus in Neonates and Infants

Hepatitis C virus prevalence has steeply risen among pregnant women in association with the opioid epidemic and the major national infectious diseases and liver society guidelines recommend universal hepatitis C virus testing in pregnancy. All infants born to mothers with hepatitis C virus infection should be evaluated. Many children spontaneously clear hepatitis C virus or remain minimally symptomatic, but some develop significant liver disease if untreated. With hepatitis C virus cure available starting at age 3, we must improve programs to identify and cure hepatitis C virus-infected women and infants with the goal of eliminating mother-to-child transmission.

Hepatitis C in children

Mother-to-child, or vertical transmission, of hepatitis C virus is now the dominant mode of acquisition of infection for children. The rate of transmission is low in women who are not also HIV-positive. Whether the mode of delivery is associated with transmission remains questionable; breast-feeding does not appear to be a source of infection. The detection of hepatitis C virus RNA using the polymerase chain reaction is a sensitive method for the early diagnosis of infection in perinatally exposed infants, but false positive results can occur. The natural history of hepatitis C virus infection in children is not well defined, but chronic infection is common in most cases. The disease progression is slower than in adults. Therapeutic trials (not placebo controlled) in a small number of children suggested a sustained response to interferon treatment in only a minority of cases. The option of combination therapy with ribavirin looks promising and needs evaluation.

Impact of maternal HIV coinfection on the vertical transmission of hepatitis C virus: a meta-analysis

BACKGROUND

Observational studies suggest that maternal human immunodeficiency virus (HIV)-hepatitis C virus (HCV) coinfection is associated with increased odds of vertical HCV transmission. We performed a meta-analysis to summarize current evidence.

METHODS

We systematically searched for relevant articles published during the period from January 1992 through July 2006 and independently abstracted articles that met our inclusion criteria. Under a random effects model, we calculated the pooled odds ratio for vertical HCV transmission according to maternal HIV-HCV coinfection status and performed sensitivity analyses.

RESULTS

Ten articles met our inclusion criteria. Study quality varied widely, and study estimates displayed high statistical heterogeneity. Restriction of the analysis to studies that included >50 HIV-HCV-coinfected women provided our most reliable estimate: maternal HIV-HCV coinfection increases the odds of vertical HCV transmission by approximately 90% (odds ratio, 1.9; 95% confidence interval, 1.36-2.67), compared with maternal HCV infection alone. When we restricted analyses to HIV-infected mothers with HCV viremia, the odds of vertical HCV transmission were 2.82-fold (95% confidence interval, 1.17-fold to 6.81-fold) greater than the odds for HIV-infected mothers without HCV viremia.

CONCLUSIONS

HIV-HCV-coinfected women have significantly higher odds of transmitting HCV to their infants than do women who are infected with HCV alone.

Perinatal hepatitis C virus infection: diagnosis and management

Hepatitis C virus (HCV) infection in children is becoming an increasing challenge to health professionals. As our understanding of the disease evolves, so must our diagnostic and management strategies. In the 1990s, when HCV testing became available, children identified with HCV infection in the UK were mostly those who had required blood products, particularly those with haematological disorders. Acquiring knowledge of the natural history of HCV infection was confounded by the co-morbidity of iron overload, viral co-infection, and chemotherapy.

Prospective study of mother-to-infant transmission of hepatitis C virus: a 10-year survey (1990-2000)

BACKGROUND

The purpose of this study was to determine the rate of vertical transmission of hepatitis C virus (HCV). We also aimed to analyze the time of clearance of maternal antibodies in the serum of non-infected babies.

METHODS

Between March 1990 and March 2000, 170 consecutive anti-HCV-positive women and their 188 babies entered this prospective study. All women were analyzed for HCV-RNA using polymerase chain reaction (PCR). The babies were followed-up until HCV-antibody clearance or until the diagnosis of HCV infection.

RESULTS

The vertical transmission rate was 2.7% overall, and it was higher in HIV co-infected women (5.4%, 2/37) than in HIV-negative women (2.0%, 3/151). All infected infants were born to mothers who had HCV viremia at delivery. The transmission rate was influenced by maternal levels of viremia. 37.2% of uninfected children became HCV-antibody negative by 6 months and 88.0% by 12 months. Babies born from HCV-RNA-positive mothers lost anti-HCV antibodies later (9.21 +/- 3.72 months) than babies born from HCV-RNA-negative mothers (7.47 +/- 3.46 months) ( p < 0.05, Kolmogorov-Smirnov test).

CONCLUSIONS

The risk of HCV vertical transmission is very low in HCV-positive/HIV-negative women and it is restricted to infants born to HCV viremic mothers. High maternal viral load is predictive of the vertical transmission. The clearance time of antibodies in non-infected babies is significantly longer if the mother is viremic.

Mother-to-infant transmission of hepatitis C virus: rate of infection and assessment of viral load and IgM anti-HCV as risk factors

One hundred twenty-six mother-infant couples were studied and 105 exposed babies were monitored for at least 12 months to define the risk of mother-to-infant HCV transmission. Infection occurred in 5 out of 76 infants (6.6%) born to 69 viraemic mothers and in none of 29 born to 26 non-viraemic mothers. Only one child was HCV RNA positive one month after birth, while the remaining children became positive at the 3rd to 4th month. HCV genotypes of the babies matched those of their mothers. No difference was found between women who transmitted the virus and those who did not with regard to age, history of drug abuse, HIV infection, ALT abnormal values, HCV genotype, type of delivery, and breast-feeding. Four out of 5 infected infants were born to mothers with IgM anti-HCV (P = 0.04). The mean viral titre in transmitting women (10(7.2)) was higher than in non-transmitting (10(6.5)), and the proportion of mothers with viral load > or = 10(7) was statistically higher in transmitting than non-transmitting women (P = 0.03). These data show that HCV perinatal infection is a rare event and suggest that IgM positivity and high viral load (> or = 10(7)) in the mother are independent variables correlated with HCV transmission (O.R. = 14.5; 95% CI: 1.3-160.7 and O.R. = 16.3; 95% CI: 1.5-179.9, respectively).

Vertical transmission of hepatitis C virus in a cohort of 2,447 HIV-seronegative pregnant women: a 24-month prospective study

BACKGROUND

Mother to infant transmission of hepatitis C virus (HCV) has been extensively studied in mothers with human immunodeficiency virus (HIV) infection, whereas fewer data are available on the vertical HCV transmission in HIV-negative women.

METHODS

Between January 1995 and June 1997, 78 consecutive HCV-positive/HIV-negative women with their offspring entered this prospective study aimed to define the prevalence of and risk factors for HCV vertical transmission. Risk factors for HCV were carefully sought, and HCV viral load and genotype were determined in all positive mothers. The infants were tested for alanine aminotransferase (ALT) and HCV-RNA at birth and at 4, 8, 12, 18, and 24 months of age.

RESULTS

Eight of 60 (13.3%) infants born to HCV-RNA positive mothers acquired HCV infection, but only 2 (3,3%) were still infected by the end of follow-up. Infants' genotypes matched that of the mothers. ALT levels were in the normal range in all study subjects throughout the follow-up. High maternal viral load (P < 0.05), possession of HCV risk factors (P < 0.004), and history of blood transfusion (P < 0.05) were associated with increased risk of HCV vertical transmission.

CONCLUSIONS

This long-term prospective study shows that, although vertical transmission from HIV-negative mothers occurs in 13% of cases, there is a high rate of spontaneous viral clearance (75%). High maternal viral load and mothers belonging to HCV risk categories were the only variables predictive of the vertical transmission.

Timing and interpretation of tests for diagnosing perinatally acquired hepatitis C virus infection

The diagnosis of hepatitis C virus (HCV) infection in children born to HCV-infected women is based on serologic assays and HCV RNA measurement by PCR. Interpretation of the results of these tests is hampered by uncertainty about the age distribution of loss of maternal antibody and the sensitivity and specificity of PCR at different ages. On the basis of findings from a recent vertical transmission study, we estimated the posttest probability of a child's being infected or uninfected under several test result scenarios. These estimates may assist clinicians in assessing the likelihood of infection in an individual child and in using the currently available assays cost effectively.

Effects of mode of delivery and infant feeding on the risk of mother-to-child transmission of hepatitis C virus. European Paediatric Hepatitis C Virus Network

OBJECTIVE

To investigate the effects of mode of delivery and infant feeding on the risk of mother-to-child transmission of hepatitis C virus.

DESIGN

Pooled retrospective analysis of prospectively collected data.

SAMPLE

Data on hepatitis C virus seropositive mothers and their children identified around delivery were sent from 24 centres of the European Paediatric Hepatitis C Virus Network.

MAIN OUTCOME MEASURES

Hepatitis C virus infection status of children born to hepatitis C virus infected women.

RESULTS

A total of 1,474 hepatitis C virus infected women were identified, of whom 503 (35%) were co-infected with HIV. Co-infected women were more than twice as likely to transmit hepatitis C virus to their children than women with hepatitis C virus infection alone. Overall 9.2% (136/1,474) of children were hepatitis C virus infected. Among the women with hepatitis C virus infection-only, multivariate analyses did not show a significant effect of mode of delivery and breastfeeding: caesarean section vs vaginal delivery OR = 1.17, P = 0.66; breastfed versus non-breastfed OR = 1.07, P = 0.83. However, HIV co-infected women delivered by caesarean section were 60% less likely to have an infected child than those delivered vaginally (OR = 0.36, P = 0.01) and those who breastfed were about four times more likely to infect their children than those who did not (OR = 6.41, P = 0.03). HIV infected children were three to four times more likely also to be hepatitis C virus infected than children without HIV infection (crude OR = 3.76, 95% CI 1.89-7.41).

CONCLUSIONS

These results do not support a recommendation of elective caesarean section or avoidance of breastfeeding for women with hepatitis C virus infection only, but the case for HIV infected women undergoing caesarean section delivery and avoiding breastfeeding is strengthened if they are also hepatitis C virus infected.

[Breastfeeding and hepatitis C virus (HCV): the need for a careful appraisal]

We review the available data on the possible role of breast-feeding in hepatitis C virus (HCV) transmission to infants of HCV-RNA-positive mothers. Current knowledge about HCV excretion through breast milk, HCV infection of breast-fed infants by mothers contaminated after delivery, and vertical transmission risk to infants breast-fed by chronic HCV viremic mothers are presented. Vertical transmission risk by breast-feeding HCV-RNA-positive mothers is unclear: no study has been performed with the aim and the required methodology to evaluate HCV transmission risk related to breast-feeding duration. Recommendations to HCV-RNA-positive mothers who wish to breast-feed their infant are discussed in light of present knowledge about HCV secretion in breast milk, mother-to-infant HCV transmission, and historical records on vertical transmission of other viruses to infants breast-fed by their viremic mothers.

Diagnosis and Monitoring of Hepatic Injury. I. Performance Characteristics of Laboratory Tests

Purpose: To review information on performance characteristics for tests that are commonly used to identify acute and chronic hepatic injury.

Data Sources and Study Selection: A MEDLINE search was performed for key words related to hepatic tests, including quality specifications, aminotransferases, alkaline phosphatase, γ-glutamyltransferase, bilirubin, albumin, ammonia, and viral markers. Abstracts were reviewed, and articles discussing performance of laboratory tests were selected for review. Additional articles were selected from the references.

Guideline Preparation and Review: Drafts of the guidelines were posted on the Internet, presented at the AACC Annual Meeting in 1999, and reviewed by experts. Areas requiring further amplification or literature review were identified for further analysis. Specific recommendations were made based on analysis of published data and evaluated for strength of evidence and clinical impact. The drafts were also reviewed by the Practice Guidelines Committee of the American Association for the Study of Liver Diseases and approved by the committee and the Association’s Council.

Recommendations: Although many specific recommendations are made in the guidelines, some summary recommendations are discussed here. Alanine aminotransferase is the most important test for recognition of acute and chronic hepatic injury. Performance goals should aim for total error of &lt;10% at the upper reference limit to meet clinical needs in monitoring patients with chronic hepatic injury. Laboratories should have age-adjusted reference limits for enzymes in children, and gender-adjusted reference limits for aminotransferases, γ-glutamyltransferase, and total bilirubin in adults. The international normalized ratio should not be the sole method for reporting results of prothrombin time in liver disease; additional research is needed to determine the reporting mechanism that best correlates with functional impairment. Harmonization is needed for alanine aminotransferase activity, and improved standardization for hepatitis C viral RNA measurements.

Mother-to-child transmission of hepatitis C virus: evidence for preventable peripartum transmission

BACKGROUND

Little information is available about the timing of mother-to-child transmission of hepatitis C virus (HCV), and no interventions to decrease transmission rates have been identified. We examined the effect of risk factors, including mode of delivery, on the vertical transmission rate.

METHODS

Data from HCV-infected women and their infants from three hospitals in Ireland and from a British Paediatric Surveillance Unit study of infants born to HCV-infected mothers were used to estimate the vertical transmission rate and risk factors for transmission. We used a probabilistic model using methods that simultaneously estimated the time to HCV-antibody loss in uninfected infants and the diagnostic accuracy of PCR tests for HCV RNA.

FINDINGS

441 mother-child pairs from the UK (227) and Ireland (214) were included. 50% of uninfected children became HCV-antibody negative by 8 months and 95% by 13 months. The estimated specificity of PCR for HCV RNA was 97% (95% CI 96-99) and was unrelated to age; sensitivity was only 22% (7-46) in the first month but rose sharply to 97% (85-100) thereafter. The vertical transmission rate was 6.7% (4.1-10.2) overall, and 3.8 times higher in HIV coinfected (n=22) than in HIV-negative women after adjustment for other factors (p=0.06). No effect of breastfeeding on transmission was observed, although only 59 women breastfed. However, delivery by elective caesarean section before membrane rupture was associated with a lower transmission risk than vaginal or emergency caesarean-section delivery (odds ratio 0 [0-0.87], p=0.04, after adjustment for other factors).

INTERPRETATION

The low sensitivity of HCV RNA soon after birth and the finding of a lower transmission rate after delivery by elective caesarean section suggest that HCV transmission occurs predominantly around the time of delivery. If the findings on elective caesarean section are confirmed in other studies, the case for antenatal HCV testing should be reconsidered.

Active surveillance of hepatitis C infection in the UK and Ireland

AIM

To investigate the prevalence, distribution, and clinical details of paediatric hepatitis C virus (HCV) infection in the UK and Ireland.

METHODS

Active monthly surveillance questionnaire study coordinated through the British Paediatric Surveillance Unit, to all consultant paediatricians in 1997 and 1998.

RESULTS

A total of 182 HCV infected children were reported from 54 centres and by paediatricians from eight different specialties. In 40 children HCV was acquired through mother to child transmission (MTC children); 142 were infected by contaminated blood products (n = 134), organ transplantation (n = 2), needles (n = 4), or unknown risk factor (n = 2). Intravenous drug use was the risk factor for 35 mothers of MTC children. Twelve children were coinfected with HIV and four with HBV. Recent serum aspartate aminotransferase or alanine aminotransferase values were at least twofold greater than the upper limit of normal in 24 of 152 children; this occurred in five of 11 HIV coinfected children. Liver histology, available in 53 children, showed normal (7%), mild (74%), moderate (17%), or severe (2%) hepatitis. Twenty eight children had received therapy with interferon alfa.

CONCLUSION

Most current paediatric HCV infection in UK and Ireland has been acquired from contaminated blood products, and most children are asymptomatic. There is a need for multicentre trials to inform clinical practice and development of good practice guidelines in this area. Long term follow up of this cohort of HCV infected children is planned to help determine the natural history over the long term of HCV acquired during infancy and childhood.

Detection of hepatitis C virus RNA (HCV RNA) in amniotic fluid: a prospective study

BACKGROUND/AIMS

Mother-to-infant transmission of hepatitis C virus (HCV) has been reported, but the transmission route is unknown. The aim of our study was to detect HCV RNA in amniotic fluid of pregnant women seropositive for HCV.

METHODS

Twenty-two HCV seropositive women were included in the study (median age: 39 years). An amniocentesis was performed in all patients during the 4th month of pregnancy. Sixteen women also tested positive for HCV RNA in serum. The range of HCV RNA titers was 0.3 to 15.1x10(6) Eq/ml (Quantiplex HCV RNA 2.0 Assay, Chiron Diagnostics). Of these 16 viremic patients, four had an anterior placenta, ten had a posterior placenta and the position of the placenta was not determined in two cases. PCR (Amplicor HCV, Roche Diagnostics) was used to detect HCV RNA in the amniotic fluid. We also studied 11 HCV seronegative women as a control group.

RESULTS

In the viremic group (n = 16), HCV RNA was detected once in amniotic fluid. The positive specimen was collected from a patient with an HCV RNA serum value equal to 1.1x10(6) Eq/ml. The placenta was in an anterior position. A PCR inhibitor was detected in one case. No HCV RNA was detected in the amniotic fluid of six seropositive non-viremic patients, nor in the control group. Serum HCV RNA was negative in the ten children tested. The woman whose amniotic fluid contained HCV RNA was the mother of one of them.

CONCLUSIONS

HCV RNA detection in amniotic fluid is rarely positive. The anterior position of the placenta in the only positive detection cannot rule out contamination of the amniotic fluid during the transplacental amniocentesis.

The prevalence of hepatitis C virus infection in the United States, 1988 through 1994

BACKGROUND

Because many persons with chronic hepatitis C virus (HCV) infection are asymptomatic, population-based serologic studies are needed to estimate the prevalence of the infection and to develop and evaluate prevention efforts.

METHODS

We performed tests for antibody to HCV (anti-HCV) on serum samples from 21,241 persons six years old or older who participated in the third National Health and Nutrition Examination Survey, conducted during 1988 through 1994. We determined the prevalence of HCV RNA by means of nucleic acid amplification and the genotype by means of sequencing.

RESULTS

The overall prevalence of anti-HCV was 1.8 percent, corresponding to an estimated 3.9 million persons nationwide (95 percent confidence interval, 3.1 million to 4.8 million) with HCV infection. Sixty-five percent of the persons with HCV infection were 30 to 49 years old. Seventy-four percent were positive for HCV RNA, indicating that an estimated 2.7 million persons in the United States (95 percent confidence interval, 2.4 million to 3.0 million) were chronically infected, of whom 73.7 percent were infected with genotype 1 (56.7 percent with genotype 1a, and 17.0 percent with genotype 1b). Among subjects 17 to 59 years of age, the strongest factors independently associated with HCV infection were illegal drug use and high-risk sexual behavior. Other factors independently associated with infection included poverty, having had 12 or fewer years of education, and having been divorced or separated. Neither sex nor racial-ethnic group was independently associated with HCV infection.

CONCLUSIONS

In the United States, about 2.7 million persons are chronically infected with HCV. People who use illegal drugs or engage in high-risk sexual behavior account for most persons with HCV infection.

Hepatitis C virus infection in the mothers and infants cohort study

OBJECTIVES

To estimate the hepatitis C virus (HCV) vertical transmission rate, the effect of potential risk factors, and the pattern of HCV antibody response and viremia in HCV-infected infants.

STUDY DESIGN

The Mothers and Infants Cohort Study enrolled both human immunodeficiency virus (HIV)-seropositive and HIV-seronegative pregnant women at five obstetric clinics in New York City in a prospective cohort study between January 1986 and January 1991. HCV-infected mothers and their 122 offspring were followed-up for a minimum of 12 months for evidence of HCV infection as determined by persistent HCV antibodies or detection of HCV RNA by reverse transcription polymerase chain reaction. Comparisons among groups for categorical variables were performed using the Fisher's exact test.

RESULTS

Seven (6%; 95% confidence interval, 2%-11%) of the 122 infants were HCV-infected. There was a tendency for increased risk of transmission with maternal viral and obstetrical factors, such as coinfection with HIV (7% vs 4%), high HIV viral load (13% vs 6%), HCV viremia (8% vs 3%), vaginal delivery (6% vs 0%), and female gender of offspring (8% vs 3%), although none of the associations reached statistical significance. After loss of maternal antibody, HCV antibody seroconversion occurred at a mean age of 26 months in 3 HIV-coinfected infants compared with 7 months of age in 4 HCV-infected HIV-uninfected infants. Serial samples showed that HCV RNA persisted in 6 infants for at least 18 to 54 months.

CONCLUSIONS

Our study is in accordance with other studies that have shown low overall HCV vertical transmission risk and a trend toward higher risk with maternal risk factors such as HIV-coinfection or HCV viremia. A delay in infant HCV antibody response may be associated with HIV coinfection although larger studies are needed to confirm these findings.