There is no cure for hepatitis B, so doctors rely on vaccinations to prevent it. Hepatitis B attacks the liver, and without treatment, it may lead to life threatening complications.

The World Health Organization (WHO) estimates that 296 million people live with hepatitis B globally. This statistic includes 2.4 million individuals living in the United States.

Around 25% of people with chronic hepatitis B develop scarring of the liver (cirrhosis), liver failure, or liver cancer. However, immunizations significantly reduce a person’s chances of acquiring an infection with the virus. Doctors usually recommend that infants receive their initial hepatitis B vaccine during their first day of life.

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Hepatitis B is a serious liver infection. In some cases, it can cause liver cancer, the second leading cause of cancer deaths worldwide.

Doctors call hepatitis B a silent infection because many people do not have symptoms when they first contract it. Despite this, they can still pass the virus to others through direct contact with blood, semen, or other bodily fluids that carry the virus.

Birthing parents with the infection can also pass the virus to their infants during birth. However, every newborn is at risk because hepatitis B spreads easily.

Common symptoms of the disease include:

  • joint pain
  • fever
  • fatigue and tiredness
  • loss of appetite
  • nausea
  • vomiting
  • stomach pain
  • pale or light-colored stools
  • dark urine

People may also experience more serious symptoms as the condition progresses, including severe vomiting, yellow eyes or skin, and a swollen stomach.

The American Academy of Pediatrics (AAP) and Centers for Disease Control and Prevention (CDC) both recommend that newborns receive their first dose of the hepatitis B vaccine within their first 24 hours of life.

One reason for this is that the birth parent could pass the infection to the infant — doctors call this perinatal infection.

If a newborn contracts hepatitis B, there is a significant chance that this infection will be chronic, meaning it will persist for a long time. Without treatment, they could develop life threatening liver complications.

Children typically receive the hepatitis B vaccine as a series of three shots:

  • following birth
  • aged 1–2 months
  • aged 6–18 months

If a newborn’s birth parent has hepatitis B, they should receive the vaccine within 12 hours following birth. They also require a hepatitis B immune globulin (HBIG) shot to provide immediate protection.

Additionally, if the infant was born prematurely with low birth weight, they will receive three extra doses of the vaccine.

Babies born to mothers without hepatitis B should receive their first vaccine within 24 hours after birth. If the baby was born prematurely or had a low birth weight, they would receive their first dose at 1 month or when they leave the hospital, whichever comes first.

The main benefit of the vaccine is its effectiveness. The AAP says that if a baby receives the first dose within 24 hours of delivery, the vaccine is 75–95% effective in preventing hepatitis B transmission from parent to infant.

Additionally, if the newborn also receives the medication HBIG at the correct time with a series of follow-up vaccines, the AAP estimates that the infection rate drops to 0.7–1.1%.

Therefore, a baby needs to complete the full series of hepatitis B vaccines for the best possible protection.

Research indicates that hepatitis B vaccines are a safe and effective way to prevent hepatitis B infections.

According to the CDC, the vaccine is very safe, and the full series of the vaccine provides the highest possible level of protection from a hepatitis B infection.

Vaccines are subject to constant safety monitoring both during production and once doctors begin to administer them to people. Any signs of a potentially dangerous response to a vaccine would result in immediate recall, meaning they are generally very safe.

According to the CDC, the hepatitis B vaccine cannot cause hepatitis B.

Although manufacturers use parts of the hepatitis B virus to create the vaccine, these are inactive. They serve only to train the body to fight against the specific cells of the virus.

However, people should know that, as with any medication, the vaccine carries some risk of minor side effects. These include fussiness or soreness at the injection site. However, these usually go away within 72 hours.

Parents and caregivers can minimize these side effects with the following tips:

  • using a cool, damp cloth to ease soreness and swelling at the injection site
  • reducing fever with a cool water sponge bath
  • giving the child liquids more frequently
  • giving a nonaspirin pain reliever following advice from a doctor
  • monitoring the child for several days and contacting a doctor if there are any concerns

While many people misunderstand or misstate the dangers of some aspects of vaccination, there are still possibly severe conditions that doctors may associate with hepatitis B immunizations.

A 2017 review discusses these possible rare complications. However, it is important to note that these results do not mean that the vaccination causes these conditions — instead, there may be an association between them.

Possible conditions include:

  • the abnormal cessation of breathing, called apnea, in preterm babies
  • vasculitis, or inflammation of the blood vessels
  • a hypotonic-hyporesponsive episode, which causes muscular issues and pale skin
  • immune thrombocytopenic purpura, which causes red spots on the skin

An infant may also have an extreme allergic reaction to the vaccine in very rare cases. Any signs of anaphylaxis, such as the baby appearing to have trouble breathing, breaking out in a rash, or changing skin tones, indicate the need for immediate medical attention.

Anaphylaxis is a severe allergic reaction that can be life threatening. The symptoms develop suddenly and include:

  • hives
  • swelling of the face or mouth
  • wheezing
  • fast, shallow breathing
  • a fast heart rate
  • clammy skin
  • anxiety or confusion
  • dizziness
  • vomiting
  • blue or white lips
  • fainting or loss of consciousness

If someone has these symptoms:

  1. Check whether they are carrying an epinephrine pen. If they are, follow the instructions on the side of the pen to use it.
  2. Dial 911 or the number of the nearest emergency department.
  3. Lay the person down from a standing position. If they have vomited, turn them onto their side.
  4. Stay with them until the emergency services arrive.

Some people may need more than one epinephrine injection. If the symptoms do not improve in 5–15 minutes, or they come back, use a second pen if the person has one.

The main risk of the baby not getting the vaccine is that they may contract the hepatitis B virus.

Hepatitis B primarily attacks the liver, causing inflammation that can damage this organ over time. An acute infection lasts for less than 6 months and may cause no symptoms in some people.

Many acute infections resolve without treatment. If the infection persists for 6 months or more, doctors will refer to it as chronic. Chronic infections increase a person’s risk of damage to the liver over time.

As this damage builds up, it can scar the liver, which is known as cirrhosis. This long-term damage may result in other complications, including liver cancer.

According to the WHO, about 820,000 people die each year from liver failure or liver cancer resulting from hepatitis B.

Experts consider the hepatitis B vaccine to be safe and effective.

People should ideally receive the vaccine at as young an age as possible to protect them from contracting hepatitis B. The AAP recommends vaccinating newborns on the day of their birth.