Hepatitis C response to treatment
Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver. The HCV infection is an important cause of morbidity and mortality worldwide. Here, it affects 1% of the general adult population and 0.3% 0f the pediatric population. In general, the importance of this illness lies in its high frequency of evolution to being chronic (60 - 80%) with a possibility of development, to a lesser or greater extent, into hepatic cirrhosis and/or hepatocarcinoma. Those cases of HCV that maintain an alteration of the transaminases (hepatic enzymes) for more than 6 months are considered chronic.
It is estimated that 140-170 million people are infected with HCV worldwide (3% worldwide prevalence). Only 15% of people infected with HCV remove it from the body in a spontaneus way. The remaining 85% develop chronic hepatitis C and therefore have a higher risk of developing cirrhosis and eventually hepatocellular carcinoma (HCC).
The hepatitis C virus is spread by:
- Parenteral transmission (blood, blood products, transplant of infected organs, shared needles, syringes or other equipment among users, use of non-disposable needles, contaminated surgical equipment, gamma globulins, etc.) is the easiest form of transmission.
- Vertical transmission (mother-child). Main transmission form to children. The possibility of transmission exists only in cases of mothers with viremia (PCR-RNA positive). If HIV positive is added, then the risk is increased to 20 - 30%. The moment of delivery is considered the moment of transmission but it has been suggested that it could also happen during gestation.
- Horizontal transmission: (contact at home with infected individuals). The possibility exists but is of little relevance. It is associated with inadvertent direct contact with contaminated blood through use of razors, toothbrushes, etc.
- Sexual transmission.
The hepatitis C virus is not contagious simply being near an infected individual, by shaking hands or by hugging.
There are six ""classes"" or sub-types of hepatitis C depending on the genetics of each one of the strains (variants) of the virus. These are called genotypes and are named by number, from 1 - 6. The distinct genotypes condition a variable treatment response. Genotype 1 is the most frequent with 75% of the hepatitis patients in this genotype. However, the persons in this genotype do not respond as well to treatment as those in the other genotypes.
In general terms, treatment consists of administering different drugs with the objective of eliminating the virus from the liver and circulation. Traditionally, two types of therapies have been used:
- Antiviral: act directly on the virus, impeding its replication
- Interferon treatment: a group of immunomodulators that act on the immune system, empowering and maintaining an adequate defense against the infection.
Since the two treatment can strengthen one another, a combined therapy, with one or two drugs, is given using both forms at the same time. However, a large number of patients cannot receive one of the most utilized types of interferon since it interferes with other illnesses (cardiac, hematologic and autoimmune illnesses among others) or because they suffer from serious adverse side effects. As a result, alternative treatments without interferon are being researched, including the administration of combination with new more effective antiviral drugs.
In general, interferon is well tolerated and the side effects that cause treatment suspension are infrequent.
Current studies in the adult population have demonstrated that the association of an antiviral (ribavirin) improved this response for all types of patients with a sustained response after 48 weeks of treatment of a 38 - 43% vs. the 13 - 19% obtained with interferon alone. The availability of a form of interferon attached to a ethylene glycol molecule (pegylated interferon) that has a longer average life and an improved pharmacokinetics facilitates the ease of administration, making weekly administration possible and bettering the response by almost double when compared to the former interferon. For this reason, the current treatment is based on the combination of pegylated alpha interferon and ribavirin.
Chronic hepatitis C treatment also includes following a balanced diet, drinking abundant liquid, avoiding alcohol and getting exercise. For end-stage hepatitis, a liver transplant may be the only treatment option.
In the great majority of cases (85%), hepatitis C is asymptomatic, being diagnosed only by chance or on screening patients with a known risk (from transfusions, contact with infected family members, etc.)
Some individuals may experience symptoms although these may be unspecific (asthenia, anorexia, abdominal pain among others). Specific symptoms of hepatic disorders such as jaundice are not usual. In adults, the accompanying extrahepatic manifestations of chronic hepatitis C are frequent and typical such as cryoglobulinemia and arthralgia, autoimmune illnesses of any organ, etc. that occasionally exacerbate the prognoses and hinder treatment.
There is no existing vaccine that can prevent HCV; therefore preventative measures should be directed towards avoiding contagion by hygienic-sanitary improvement.
Patient prophylaxis: avoid all causing factors of a hepatic lesion (alcohol, excess iron, hepatotoxic drugs). Vaccinations against Hepatitis A and B
- Vertical transmission: Breastfeeding and the delivery method do not favor the transmission; therefore breastfeeding should not be discouraged nor is pregnancy counterindicated for women with chronic HCV hepatitis.
- Horizontal transmission: avoid sharing razors, depilatories, toothbrushes, scissors, etc. Stable partners should use contraception methods that impede the transmission by sexual means.
Gene or region studied