Combating Infectious Hepatitis

On the 28th of July, World Health Organization will observe its annual “World Hepatitis Day” event across the globe, to increase awareness and understanding of the impact of hepatitis. In lieu with this campaign of the organization, it is best that this month’s edition of YourHealthNews will tackle a brief description of the disease and its complications, methods of prevention, and recent scientific breakthroughs about infectious hepatitis.

What is Hepatitis?

Hepatitis is the medical term for the inflammation of the liver, most commonly due to an infection of a virus. In this regard, it is commonly termed as infectious hepatitis to differentiate it from other forms of hepatitis of non-infectious causes such as drugs, alcohol and other metabolic causes. Besides, majority of acute hepatitis are commonly cause by an infection, particularly viruses.

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Hepatitis viruses can either be classified as A, B, C, D, E and G. The most common amongst these types are hepatitis A, B and C. Hepatitis D is usually a co-infection to hepatitis B, as it is dependent on the hepatitis B virus for its own replication.

Hepatitis A is caused by a RNA virus of the family Picornaviruses and termed as hepatitis A virus (HAV). Infection with HAV is usually through the faecal-oral route, which means that uninfected individuals can be infected when they ingest food and/or water that is contaminated with the faeces of an infected individual. Outbreaks of Hepatitis A are associated with insufficient sanitation, limited safe water resources and poor personal hygiene. In most developed countries, introduction of HAV vaccine in the 1990s have decreased incidence of hepatitis A infection. However, cases are still common especially amongst international travellers who visited endemic countries.

Amongst the types of hepatitis, hepatitis B and C are known to be associated with chronic disease that can lead to liver cirrhosis and/or liver cancer. The hepatitis B virus is a double-stranded DNA Hepadnavirus, whereas hepatitis C virus is a single-stranded RNA Hepacivirus. Both types of hepatitis are transmitted by direct contact with contaminated bodily fluids, in particular blood from an infected person. Thus, prevention can be done by avoiding practices that can increase the likelihood of being infected with contaminated bodily fluids such as sharing of unsterile or used needles either for medical or recreational use and having unprotected sexual encounters. For hepatitis B infection, the most effective way to prevent acquiring the virus is through vaccination.

Since both hepatitis B and C can lead to chronic disease, most cases are unaware that they carry the virus because they usually have no symptoms. It is, therefore, recommended that screening for these types of hepatitis be done especially amongst those who are at increase risk of acquiring the infection. These high risk individuals include patients who inject with recreational drugs, those who have multiple sexual partners, and those who have unprotected sexual encounters with infected individuals as well as those who are born to mothers who have the virus.

Once screening is done and showed positive results for infection, care and management of infection is aimed at controlling the progression of the disease to its late complications. Chronic hepatitis B infection, in some patients, can be treated with antiviral drugs and interferons. On the other hand, the current mainstay for treatment for hepatitis C infection is a combination antiviral therapy with interferon and ribavirin.

Similar to the mode of transmission of HAV is hepatitis E caused by the RNA Hepevirus. The infection is a predominant acute hepatitis in Central and Southeast Asia, the Middle East, and North Africa. Sporadic cases seen in industrialised countries are those with history of travel or visit to these endemic areas. In contrast to HAV, HEV is associated with high mortality due to acute liver failure amongst pregnant women who acquire the infection.

At present, since no effective treatment is discovered yet for hepatitis E, preventive measures such as those for hepatitis A should also be done, in particular, avoiding drinks made from unsterilized water. Similar to hepatitis A, hepatitis E has an available vaccine which is registered in China in 20111; however, it is still not marketed worldwide.

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The Latest Breakthroughs

Amongst the various hepatitis types, latest breakthroughs are accounted on hepatitis B and C. One of the promising breakthroughs of the past year is the development of newer antiviral drugs for hepatitis C, telaprevir and boceprevir.2 These two drugs are incorporated to the latest regimen of drugs for chronic hepatitis C sufferers especially those who have failure treatment on the standard treatment.3 Another antiviral drug against hepatitis C, sofosbuvir, has also provided promising results in phases 2 and 3 trials.4,5 With these developments, patients with hepatitis C infection will have more choices to their medical regimens suitable for them with lesser adverse reactions. Further, it also gives hope to those who have treatment failure on the combined interferon and ribavirin treatment regimen.

In hepatitis B infection, the latest study conducted by German researchers showed that low levels of vitamin D is associated with higher levels of HBV replication.6 This study further adds to growing evidence that vitamin D plays an important role in inflammatory and metabolic liver disease, enabling future research studies to understand if vitamin D may particularly be vital as an adjunct to treatment regimens for HBV.

Furthermore, a recent study found that tenofovir (an antiviral used in HBV infection) can avert complications of HBV infection such as liver fibrosis and cirrhosis in at least 5-years of taking the drug7, which can eventually decrease the occurrence of liver cancer associated with chronic HBV infection in the future.

Advancing developments in treatment, prevention and theoretical understanding of infectious hepatitis may point to a glimmering hope of combating the disease in the years to come.

References:

  1. Hoofnagle JH, Nelson KE, Purcell RH. Current concepts: Hepatitis E. N Engl J Med 2012; 367:1237-1244.
  2. Butt AA, Kanwal F. Boceprevir and telaprevir in the management of hepatitis C virus-infected patients. Clin Infect Dis 2012; 54(1):96-104.
  3. Sitole M, Silva M, Spooner L, Comee MK, Malloy M. Telaprevir versus boceprevir in chronic hepatitis C: A meta-analysis of data from phase II and III trials. Clinical Therapeutics Feb 2013; 35(2):190-197.
  4. Kowdley KV, Lawitz E, Crespo I, Hassanein T, Davis MN, DeMicco M et.al. Sofosbuvir with pegylated interferon alfa-2a and ribavirin for treatment –naïve patients with hepatitis C genotype-1 infection (ATOMIC): An open-label, randomised, multicentre phase 2 trial. The Lancet June 2013; 381(9883):2100-2107.
  5. Lawitz E, Mangia A, Wyles D, Rodrigues-Torres M et.al. Sofosbuvir for previously untreated chronic hepatitis C infection. N Engl J Med 2013; DOI:10.1056/NEJMoa1214853.
  6. Farnik H, Bojunga J, berger A, Allwinn R et.al. Low vitamin D serum concentration is associated with high levels of hepatitis B virus (HBV) replication in chronically infected patients. Hepatology 2013; DOI:10.1002/hep.26488.
  7. Marcellin P, Gane E, Buti M, Afdhal N, Sievert W et.al. Regression of cirrhosis during treatment with tenofovir disoproxil fumarate for chronic hepatitis B: A 5-year open-label follow-up study. The Lancet February 2013; 381(9865):468-475.