Intrafamilial spread of hepatitis C virus infection

Hepatitis C virus infection in the family setting of patients with occult hepatitis C

Family members of patients with chronic hepatitis C virus (HCV) infection are at increased risk of HCV infection but the prevalence of HCV among family members of patients with occult HCV infection is not known. Anti-HCV, serum HCV RNA and levels of liver enzymes were determined in 102 family members of 50 index patients with occult HCV infection and in 118 family members of 59 chronic hepatitis C index patients. HCV RNA and/or anti-HCV were detected in 10/102 (9.8%) relatives of patients with occult HCV infection and in 4/118 (3.4%) of patients with chronic hepatitis C. Fourteen additional family members (seven were relatives of index patients with occult HCV infection) had abnormal values of liver enzymes without serological markers of HCV infection. Two of these patients (who were relatives of two index patients with occult HCV infection) underwent a liver biopsy and were diagnosed with an occult HCV infection because HCV RNA was detected in the liver cells in the absence of serological HCV markers. In conclusion, the prevalence of HCV infection among family members of patients with occult HCV infection was similar to that found among family members of patients with chronic hepatitis C. This stresses the need to adopt strategies to prevent the transmission of HCV in the family setting of patients with occult HCV infection.

Anti-HCV positivity in sexual partners and offspring of patient with chronic hepatitis C

We investigated the seroprevalence of HCV in stable sexual partners and offspring of chronic hepatitis C patients, and aimed to determine the risk factors involved. 191 anti-HCV and HCV RNA positive subjects who coinhabited with their spouse and/or offspring were included. Risk factors of index cases for disease transmission, liver biopsy results, anti-HCV and HCV-RNA in spouses and/or offspring were evaluated. Together with index cases, a total of 404 family members including 174 stable sexual partners and 230 offspring were included. The most common risk factors among index cases were dental procedures (73.8%), history of surgery (64.9%), and blood transfusions (24.1%). Anti-HCV positivity was established in 11 (2.7%) of the total 404 family contacts--6 sexual partners and 5 offspring. HCV seropositivity was significantly higher in the spouses of index cases with severe hepatitis C compared to those with mild to moderate hepatitis C (p=0.008), but there was no statistically significant correlation between the severity of liver disease in index cases and anti-HCV positivity in their offspring. In conclusion, anti-HCV seropositivity in the spouses and children of patients who are HCV-RNA positive HCV carriers does not appear to be higher than the HCV seroprevalence in our country.

Sexual transmission of hepatitis C

It is generally agreed that the hepatitis C virus (HCV) can be efficiently transmitted parenterally, although data on viral transmission by sexual or non-sexual intrafamilial contact are conflicting. Since data collection began in 1989, the first study dealt with the risk of sexual transmission among multiple sex partners. Other investigations followed, emphasizing that risk increases in specific groups such as patients co-infected with HIV and HBV, sex workers, homosexuals, illicit drug users and patients attended at sexually transmittable disease clinics. The question arises as to what might be the risk for monogamous heterosexuals in the general population, in which one of the partners has HCV? The literature provides overall rates that vary from zero to 27%; however, most studies affirm that the chances of sexual transmission are low or almost null, with rates for this mode fluctuating from zero to 3%. Intrafamilial transmission is strongly considered but inconclusive, since when mentioning transmission between sex partners within the same household, specific situations also should be considered, such as the sharing of personal hygiene items, like razorblades, toothbrushes, nail clippers and manicure pliers, which are important risk factors in HCV transmission. In this review, we discuss the hypotheses of sexual and/or intrafamilial transmission.

Lack of evidence of sexual transmission of hepatitis C among monogamous couples: results of a 10-year prospective follow-up study

The risk of sexual transmission of hepatitis C virus (HCV) infection was evaluated among 895 monogamous heterosexual partners of HCV chronically infected individuals in a long-term prospective study, which provided a follow-up period of 8,060 person-years. Seven hundred and seventy-six (86.7%) spouses were followed for 10 yr, corresponding to 7,760 person-years of observation. One hundred and nineteen (13.3%) spouses (69 whose infected partners cleared the virus following treatment and 50 who ended their relationship or were lost at follow-up) contributed an additional 300 person-years. All couples denied practicing anal intercourse or sex during menstruation, as well as condom use. The average weekly rate of sexual intercourse was 1.8. Three HCV infections were observed during follow-up corresponding to an incidence rate of 0.37 per 1,000 person-years. However, the infecting HCV genotype in one spouse (2a) was different from that of the partner (1b), clearly excluding sexual transmission. The remaining two couples had concordant genotypes, but sequence analysis of the NS5b region of the HCV genome, coupled with phylogenetic analysis showed that the corresponding partners carried different viral isolates, again excluding the possibility of intraspousal transmission of HCV. Our data indicate that the risk of sexual transmission of HCV within heterosexual monogamous couples is extremely low or even null. No general recommendations for condom use seem required for individuals in monogamous partnerships with HCV-infected partners.

Intrafamilial transmission of hepatitis C virus: a systematic review

To examine the risk of hepatitis C virus (HCV) transmission between patients infected with HCV and their household members (siblings, offspring and parents), as well as their stable heterosexual partners, a systematic search of the MEDLINE database was undertaken for all relevant articles published up to June 1997. English language publications or those supplemented with an English abstract that reported studies concerning hepatitis C, and household, intrafamilial, sexual and intraspousal transmission of HCV, were reviewed. Data from uncontrolled and controlled studies were collected and analysed separately. Studies reporting the exclusive use of first-generation anti-HCV antibodies without supplemental tests were excluded. Pre- or postnatal mother-to-child transmission of HCV and homosexual and heterosexual transmission of HCV among non-permanent couples were not included. Unweighted data from individual studies were pooled for each category of family member. Data were also analysed separately for Japanese and non-Japanese studies because there is evidence that intrafamilial transmission may differ, based on endemicity of the viral infection. Comparisons were drawn only from controlled studies that reported the prevalence of HCV in family members of both HCV-positive and HCV-negative controls. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated for each family category. In uncontrolled studies, the pooled prevalence of anti-HCV among 4250 stable sexual contacts of patients with HCV-related chronic liver disease (CLD) was 13.48%, while the pooled prevalence of anti-HCV among 580 stable sexual contacts of patients who contracted HCV as a result of multiple transfusions was 2.41%. In controlled studies, the pooled prevalence of anti-HCV among 175 siblings and household contacts of patients with CLD was 4.0% compared with 0% among 109 contacts of anti-HCV-negative controls (OR 9.75, 95% CI 0.91 ad infinitum). The pooled prevalence of anti-HCV among offspring of Japanese HCV-infected CLD patients was 17% compared with 10.4% among offspring of HCV-negative Japanese controls (OR 1.77, 95% CI 1.21-2. 58, P=0.002). The pooled prevalence of anti-HCV among spouses of non-Japanese HCV-infected CLD patients was 15.2% compared with 0.9% in the spouses of non-Japanese HCV-negative controls (OR 20.57, 95% CI 6.05-84.08, P=0.0001). The prevalence of anti-HCV among non-Japanese offspring and Japanese spouses of HCV-infected patients was not increased compared with controls. HCV genotype homology and mutant analysis studies in pairs of HCV-infected patients and their HCV-infected contacts showed that concordant genotype homology was found in 66% of non-sexual contacts and in 74% of sexual contacts. Sequence homology of greater than 92% was found in 19 out of 35 pairs. Hence, evidence exists that familial, non-sexual and sexual transmission of HCV does occur. In Japanese patients, transmission probably occurs in younger family members while, in non-Japanese patients, transmission probably occurs at an older age, after contact with an HCV-infected spouse.

Sexual transmission of hepatitis C virus infection

BACKGROUND

Hepatitis C virus (HCV) is the cause of almost all cases of parenterally transmitted non-A, non-B viral hepatitis (NANBH). HCV is an RNA virus, unrelated to the hepatitis viruses, A, B, D, or E; it was first identified in 1989. Although most infections become chronic, and it may lead to chronic liver disease, most patients with HCV infection are asymptomatic. The predominant modes of transmission are by blood, blood products, or other parenteral exposure, particularly injecting drug use. More contentious is the role of sexual transmission, although evidence for this was provided by studies of NANBH.

OBJECTIVE

This review considers the evidence for sexual transmission, and the types of studies used to estimate the rate of transmission and the factors that may influence it.

METHOD

A Medline search using the keywords hepatitis C, sex, transmission, and prevalence in MeSH and free text. References in papers were searched, and some unpublished data identified. References were further selected to illustrate different methodologies.

FINDINGS

Evidence for sexual transmission is provided by several types of study including prevalence studies in groups at risk of other STDs, investigation of cases identified from surveillance reports, and cross sectional and longitudinal partner studies. Many studies are limited by their small size, the sensitivity and specificity of early assays, lack of controls, or the difficulty of excluding other routes of transmission. One prospective cohort study reported an incidence of 12 per 1000 person years in the sexual partners of HCV infected patients. 1-3% of partners of HCV infected patients are found to be infected in cross sectional studies. Co-infection with HIV, duration of the relationship, or chronic liver disease may be independent cofactors increasing the risk of transmission. A meta-analysis of selected studies may be informative, and further larger prospective studies are required. There is a small but definite risk of sexual transmission of hepatitis C.

Intrafamily transmission of hepatitis C virus: sexual and non-sexual contacts

BACKGROUND/METHODS

As a high number of patients with antibodies to hepatitis C (anti-HCV) do not have a known history of parenteral acquisition, other non-parenteral means of hepatitis C virus transmission must be studied. We investigated 1451 household contacts of 535 anti-HCV positive, human immunodeficiency virus-negative index patients.

RESULTS

Overall, the prevalence of anti-HCV in household contacts was 4.5%. Thirty (7.6%) out of the 394 heterosexual stable partners were anti-HCV positive as compared to 35 (3.3%) out of 1057 non-sexual contacts (p < 0.01). The prevalence of anti-HCV was lowest in children of the index cases (1.8%). In this group, the prevalence of anti-HCV was 3% (10/330) when the mother was the index case, as opposed to 0.6% (2/328) when the father was the index case (p < 0.05). The prevalence of anti-HCV increased with age, being highest (18.6%) in family contacts older than 60 years.

CONCLUSIONS

Transmission of hepatitis C virus may occur among household contacts of anti-HCV positive patients. Sexual contact or the use of non-disposable medical material in the past might explain the higher prevalence of anti-HCV found in sexual partners and in family contacts older than 60 years of age. Anti-HCV screening should be performed in family contacts of anti-HCV positive patients, particularly in those contacts older than 20.

Methods of transmission of hepatitis C

The route of transmission of hepatitis C virus is still controversial. Parenteral exposure via blood or blood products leads to infection in the majority of cases, and the majority of intravenous drug users become infected by repetitive exposure to contaminated injection equipment. The risk of infection from a single needlestick injury is 5-15% and may depend on the size of the innoculum. Other parenteral routes of transmission may include traditional healing practices and the use of contaminated medical equipment. Transmission is less common within a family but the prevalence of hepatitis C viral antibodies is higher in family members and sexual partners of carriers than in the general population. There are some well-documented instances of acute hepatitis C occurring after a defined sexual exposure. Vertical transmission is rare unless the mother has high levels of circulating HCV RNA as may occur in those also infected with HIV. The detection of hepatitis C in saliva and the higher than expected prevalence of infection in dentists may point to the possibility of transmission by salivary contamination. There remain large numbers of hepatitis C carriers in whom no route of infection can be identified.

Prevalence and determinants of anti-HCV seropositivity and of HCV genotype among intravenous drug users in Berlin

A cross-sectional study was carried out to identify risk factors for seropositivity for antibodies against hepatitis C virus (HCV) and to assess to the distribution and determinants of HCV genotypes among intravenous drug users (IVDUs). The study population consisted of 405 IVDUs. Serum specimens were tested for seromarkers for HCV, for human immunodeficiency virus (HIV), for hepatitis B virus (HBV) and for syphilis. HCV RNA determination by polymerase chain reaction (PCR) and virus typing were performed in a subsample of anti-HCV-positive specimens (n=135). Of the IVDUs, 83% were anti-HCV-positive, 18% HIV-infected, and 58% HBV (anti-HBc)-positive. Longer duration of intravenous drug use, syringe sharing in prison, and higher number of IDVU sex partners were independent risk factors for anti-HCV positivity. GCV RNA was detected in 76% of anti-HCV-positive IVDUs. HCV genotypes 1 (49%) and 3 (44%) were most commonly found. All the type 3 isolates were identified as subtype 3a, and 95% of the type 1 isolates as subtype 1b. In logistic regression analysis, HCV type 3a viraemia was significantly associated with lack of HIV infection and a higher number of sex partners. The results indicate that preventive measures are needed to reduce syringe sharing among IVDUs in prisons. Sexual contacts with other IVDUs may play a role in the HCV epidemic among IVDUs. In Germany, HCV type 3a infection appears to be much more common among IVDUs than among other HCV risk groups such as transfusion recipients or haemophiliacs.