Currently, over 2 billion people in the world are estimated to have been infected with HBV, of which 75% are Asians. Why is hepatitis B so prevalent in Asia?
Hepatitis B Virus (HBV) infection is a global health problem. Currently, over 2 billion people in the world are estimated to have been infected with HBV, about 400 million people with chronic HBV (HBV carrier), of which 75% are Asians. Every year, nearly 1 million people die from HBV-related illnesses such as cirrhosis, liver cancer. Why is hepatitis B so prevalent in Asia?
What is hepatitis B virus?
Hepatitis B is caused by a small virus carrying the DNA of the Hepadnaviridae family. The virus itself does not directly damage the liver cells but because the body’s immune system recognizes the infected liver cells and attacks them to damage the liver. When this process continues for a long time, the damaged liver tissue becomes scar tissue that can lead to cirrhosis and liver failure, even liver cancer.
Hepatitis B virus circulating in the blood can be transmitted through the following ways: Mother passes to her baby during labor, this is the most important way of transmitting; Sexual route: Hepatitis B virus can be transmitted through homosexual or heterosexual activity; blood sugar: Hepatitis B virus is spread by transfusion of blood or blood products from the virus; when exposed to the secretions of hepatitis B patients; using contaminated needles; acupuncture tattoo, ear piercing with tools not properly disinfected.
Hepatitis B has many different symptoms, depending on the condition and stage of the disease.
Acute hepatitis B
Occurs when the body’s immune system attacks and destroys the virus massively, this fight causes much damage to liver cells (elevated liver enzymes). Patients will have the same symptoms as the flu, sometimes feeling nauseous, vomiting, weight loss, poor appetite, itching all over. It may be more severe with fever, jaundice, yellow eyes, abdominal pain, joint pain, muscle aches, dark yellow urine, and death from fulminant hepatitis.
Chronic hepatitis B
Because the body’s immune system is not strong enough, the struggle persisted for many years. At this stage, there are almost no symptoms, patients often feel normal health or sometimes have fatigue, transient anorexia and eventually lead to serious consequences such as cirrhosis, and complications such as having Abdominal water is often called ascites, gastrointestinal bleeding, liver cancer.
Carriers, ie when the body is infected with the hepatitis B virus, usually have no signs of hepatitis. The virus appears to “live peacefully” with someone who has been infected for the rest of their life. However, at some point becoming the culprit that infects the infected person himself and spreads it to others.
Is hepatitis B dangerous?
– HBV is 100 times more infectious than HIV.
– HBV is the second leading cause of cancer after cigarette, 60-80% of cases of primary liver cancer and 50% of cirrhosis.
– HBV infection is still an important cause of morbidity and mortality.
The worldwide distribution of hepatitis B virus
In terms of HBsAg prevalence
Global HBsAg prevalence is divided into 3 levels. High when the ratio is greater than or equal to 8%, average when the rate is from 2-7% and low when the rate is <2%.
In the Asia-Pacific region, high prevalence rates include Vietnam and Western Pacific countries. According to the World Health Organization (WHO), Vietnam is one of the countries with the highest rates of HBV infection in the world, at 15% -20%, about 10 -14 million people.
Regarding the genotype of HBV
Currently HBV has 8 genotypes, A, B, C, D, E, F, G, H distributed worldwide. Vietnam is mainly infected with types B and C.
Genotypic identification is increasingly of interest because several studies have shown that the HBV genotype is associated with the following:
- HBeAg seroconversion rate: Genotype B has a higher HBeAg seroconversion rate than genotype C.
- Clinical context: acute liver failure, fulminant hepatitis is more often associated with genotype D than other genotypes.
- Progression of the disease: Genotype C is most likely to progress to hepatocellular cancer and is an independent risk factor for HCC.
- Response to treatment of chronic: genotypes A and B respond better to Interferon and Peginterferon than C and D.
Why is hepatitis B so prevalent in Asia?
- The immunization program has not been really effective and has not been widely available in the past. This leads to a high rate of acute HBV infection in many Asian countries.
- At present, patients still have difficulty accessing many drugs to treat chronic hepatitis B virus with the purpose of long-term inhibiting serum HBV DNA levels to prevent progression to cirrhosis and cancer, hepatocellular carcinoma (HCC) and death.
- Deciding when to treat, how to treat, etc. are still difficult questions for clinicians in this area.
- Longitudinal infection from mother to child, most often occurs during perinatal period or early months postpartum, non-placental infection is a common mode of infection in Asian countries. Because Asia is one of the areas where high levels of HBsAg are circulating – conditions of this contagious type.
The level of infection depends on the level of HBV DNA and the mother’s HBeAg status in the last 3 months of pregnancy. Mothers with HBeAg (+), infants have a 95% risk of infection if they do not receive immune prophylaxis. But in these countries, few babies are immunosuppressed.
- In addition, these countries often have a tradition of breastfeeding. In fact, HBsAg is present in human milk in very low concentrations. But still the transmission is caused by sucking babies bite the breast causing scratching.
Therefore, in general, the reason why is hepatitis B so prevalent in Asia is not regular health checkup, so it is not possible to detect infection with the hepatitis B virus in time, specialists for a long-term monitoring and treatment program. That has accelerated the progression of the disease hepatitis B, cirrhosis progression and liver cancer all over Asia, including Vietnam.