Hepatitis can be generally defined as a disease which causes inflammation of the liver which can turn serious and life-threatening. The causative agents of hepatitis are usually different types of viruses which are classified as hepatitis A, hepatitis B, hepatitis C, hepatitis D, and hepatitis E. Though the diseases caused by these viruses are similar, the viruses entirely vary from each other when it comes to structure.
Till date, vaccines for prevention have only been found against the viruses causing Hepatitis A and B. Additionally, a combination vaccine has also been made available which guards against both Hepatitis A and B.
- Hepatitis A and B Viruses
Containing a partially double-stranded DNA, HBV or hepatitis B virus belongs to the hepadnavirus family. On the other hand, hepatitis A virus or HAV contains single-stranded RNA and falls under the picornavirus family. Though both the viruses’ shows a great structural variation, their mode of infection is similar as they both primarily infect and replicate the liver cells.
The symptoms associated with hepatitis A infection are similar to that of hepatitis B infection. Early symptoms often include the following.
- Body pain
- Abdominal pain
- Dark coloured urine
Furthermore, symptoms accompanying the later phases of Hepatitis include;
- Pain in the upper part of the abdomen
- Light stools
Hepatitis A and E – Both HAV and HEV are transmitted by enteric routes. To put it simply, the viruses find their way into the body through digestive or faecal routes (faecal-oral routes). Poor hygiene and poor sanitary conditions are two of the main reasons that lead to the infection of these viruses.
India, Central and South America, and Bangladesh are the countries that are particularly vulnerable to the hepatitis E virus. A recent study showed that over one-third of the United States population is exposed to the hepatitis A virus.
Hepatitis B, C, and D – All three types of hepatitis viruses are transmitted through parenteral routes. Parenteral routes simply mean that the viruses are introduced into a person’s body through all routes except for the enteric routes, or intestinal tract. Taking this into account, the chances are high rates of possible exposure.
HBV can easily get transmitted through bodily fluids such as sweat, blood, saliva, and tears of an infected person. Nevertheless, not every person suffering from hepatitis B is infectious. Only a handful of people infected with HBV are thought to be contagious.
Main reasons for exposure includes sharing a syringe when getting pierced, or during childbirth. Many countries started screening for HBV in blood from 1975. Thus, there is little to no risk of contracting HBV through blood transfusions.
Similarly, HCV is transmitted primarily through blood. Therefore, blood transfusions pose a higher risk of transmission. Unlike HBV, HCV doesn’t get transmitted through childbirth and sexual contact.
HDV is transmitted exactly the same way as HBV mainly because hepatitis D virus co-exists with the hepatitis B virus. When both HDV and HBV are caught at the same time in a person, it is known as co-infection; while, when hepatitis D infects a person already suffering from hepatitis B, it is known as super-infection.
There isn’t any specific treatment to cure both acute hepatitis A and B infections as of now. The only treatment available to the patients is supportive care which includes rest, fever and pain relief, and fluid management.
In the case of Hepatitis, prevention is always better than cure. Thus, hepatitis A and B vaccines along with several other combination vaccines are made available all around the world.
The hepatitis vaccines are made part of the routine childhood immunisation schedule as newborns and young children are more prone to hepatitis infection. The vaccines are safe for people with reduced immunity as it doesn’t contain live viruses.
Hepatitis B vaccination is given as three-dose series to children starting birth within a time period of several months. If not vaccinated when young, both adolescents and adults are advised to receive the vaccine to prevent getting infected by HBV.
On the other hand, hepatitis A vaccination is recommended to be given at the age of 1 followed by a booster shot several months later. Those who haven’t received the vaccination can get a pre-departure hepatitis A vaccine before travelling to developing countries. It is important to get vaccinated at least 2 weeks before departure.
The benefits of the single administration last for several months, though receiving a second dose would add to prolonged immunity.
Lastly, hepatitis E vaccine was also made available for people of the age 16-65 who are at higher risk of HEV infection.