Hepatitis B

A tiny germ can hurt your liver.

This germ can make you feel very sick. You might feel tired or have a tummy ache. Some people's skin may even turn yellow.

This germ spreads through blood. It can pass from a mother to her baby. It can also spread if blood touches a person. You cannot catch it from hugging or kissing.

Some people stay sick for a long time. This is called a chronic sickness. It can be hard on the liver.

Doctors can use a shot to keep you safe. This shot is called a vaccine. It works very well to stop the germ.

Many countries give this shot to babies. It helps keep the world healthy.

Hepatitis B is a sickness caused by a virus. This virus attacks the liver.

Some people feel sick right away. They may feel tired or have a tummy ache. Their skin or urine might turn yellow. This yellow color is called jaundice. This sickness usually lasts a few weeks.

Other people stay sick for a long time. This is called a chronic infection. If it lasts over six months, it is chronic. Being sick for a long time can lead to liver cancer.

The virus spreads through blood or body fluids. It can pass from a mother to her baby during birth. It can also spread through contact with blood. You cannot catch it from hugging, kissing, or sneezing.

Doctors can help prevent this sickness. They use a shot called a vaccine. The vaccine is very good at stopping the virus.

Since 1982, people have used vaccines to stay safe. Many countries give this shot to babies. The World Health Organization wants to stop this sickness by 2030. They want to keep more people healthy around the world.

Hepatitis B is a sickness caused by a tiny germ called a virus. This virus specifically attacks the liver, which is a large organ in your body.

It is one of five main hepatitis viruses, which are named A, B, C, D, and E. When people first get this virus, they might feel very unwell. They may have a stomach ache, feel sick to their stomach, or feel very tired. Some people even see a yellow color in their skin or urine. This yellow color is called jaundice.

There are two main ways this sickness works in the body. An acute infection happens right after someone is exposed to the virus. These symptoms usually last a few weeks, but some people feel sick for six months. If the virus stays in the body for longer than six months, it is called a chronic infection.

This long-term sickness can be very hard on the liver. About 25% of people with chronic hepatitis B might develop liver cancer or cirrhosis. Cirrhosis is when the liver becomes damaged over many years. Younger children are more likely to develop this long-term sickness. About 90% of babies infected at birth will have the chronic version.

The virus spreads through contact with infectious blood or body fluids. In some places, the virus passes from a mother to her baby during birth. In other areas, it spreads through contact with blood during childhood. It can also spread through sexual contact or using needles that are not clean.

You do not have to worry about catching it from everyday things. You cannot get it from hugging, kissing, or holding hands. It also does not spread by coughing, sneezing, or sharing spoons. This means you can still be kind and close to others safely.

Doctors have found ways to keep people safe from this virus. Since 1982, we have used a vaccine to prevent the sickness. This vaccine is very strong and works between 98% and 100% of the time. To work fully, a person needs to get several doses of the shot. The World Health Organization says babies should get their first dose within 24 hours of birth. As of 2021, national programs provide this vaccine to infants in 190 different countries. This helps stop the virus before it can ever start.

Many people around the world are affected by this virus. In 2019, about 296 million people had a chronic infection. This is about 3.8% of all people on Earth. The disease is most common in Africa and the Western Pacific region.

The World Health Organization has a big goal for the future. They want to stop this virus from being a threat by the year 2030. To do this, they want to use more vaccines and better medicines. They also want to make sure all donated blood is tested safely.

Hepatitis B is an infectious disease caused by the hepatitis B virus, often called HBV. This virus specifically targets the liver, which is a vital organ in the human body. HBV is one of five main hepatitis viruses, alongside types A, C, D, and E.

Understanding this virus is important because it can lead to serious long-term health problems. While many people show no signs of being sick, the virus can still cause significant damage to the liver over time.

The virus has a very complex life cycle inside the human body. It is a pararetrovirus, which means it uses a process called reverse transcription to replicate.

First, the virus enters a liver cell, known as a hepatocyte, by binding to a specific receptor on the cell surface. Once inside, the viral DNA must travel to the cell nucleus using helper proteins called chaperones. In the nucleus, the viral DNA is transformed into a stable form called covalently closed circular DNA, or cccDNA. This cccDNA then acts as a template to create new viral components. These components eventually assemble into new virus particles, which are released to infect other cells.

The physical structure of the virus is quite small and specialized.

An HBV particle, or virion, is between 30 and 42 nanometers in diameter. It consists of an outer lipid envelope and an inner core called a nucleocapsid. This core protects the viral DNA and an enzyme called DNA polymerase. The outer envelope contains surface antigens, known as HBsAg, which help the virus attach to new cells. Some scientists refer to the 42 nm infectious particles as "Dane particles." The virus's genome is made of circular DNA that is only partially double-stranded.

An infection with HBV can be classified into two distinct stages: acute and chronic. An acute infection is the initial illness that occurs shortly after exposure. Symptoms may appear between 30 and 180 days after contact. These symptoms can include nausea, vomiting, fatigue, and jaundice, which is a yellowing of the skin and eyes. Most people recover from an acute infection within a few weeks or months. However, if the infection lasts longer than six months, it is considered a chronic infection. The risk of this becoming chronic is much higher for infants. About 90% of those infected at birth develop chronic HBV, compared to less than 10% of those infected after age five.

Chronic hepatitis B can be very dangerous because it often has no symptoms for a long time. Without treatment, the constant inflammation can lead to cirrhosis, which is severe scarring of the liver. This condition significantly increases the risk of developing hepatocellular carcinoma, or liver cancer. In fact, about 25% of people with chronic HBV will eventually develop cirrhosis or liver cancer. The virus can also cause issues outside of the liver, such as kidney problems or skin rashes. Because of these risks, doctors often use antiviral medications like tenofovir to help manage the disease.

Historically, hepatitis B was once known as "serum hepatitis." In the 1980s, many cases were linked to tattooing and acupuncture, but improved sterilization has made this much less common. Today, we know the virus is transmitted through contact with infectious blood or body fluids. This includes sexual contact, using contaminated needles, or vertical transmission from mother to child during birth. It is important to note that HBV is much more infectious than HIV. However, you cannot catch it through casual contact like hugging, kissing, or sharing utensils.

Global health organizations are working hard to control the spread of this virus. As of 2022, the hepatitis B vaccine is between 98% and 100% effective. This vaccine is given in several doses to ensure full protection. The World Health Organization recommends that infants receive the vaccine within 24 hours of birth. As of 2021, 190 countries have national programs to provide this vaccine to babies. In 2019, an estimated 296 million people lived with chronic hepatitis B. This represents about 3.8% of the total global population. The WHO aims to eliminate viral hepatitis as a global public health threat by the year 2030.

The impact of the virus varies greatly depending on where you live. It is most prevalent in Africa, where it affects 7.5% of the population. The Western Pacific region also has high rates at 5.9%. In contrast, the infection rate is much lower in Europe at 1.5% and in the Americas at 0.5%. Some estimates suggest that one-third of all people in the world have been infected with hepatitis B at some point. By using vaccines, testing donated blood, and improving treatments, the world hopes to reduce these numbers significantly.