How is Hepatitis B transmitted?

June 26, 2024
Avatar for Jyoti Kinghorn, PhDJyoti Kinghorn, PhD
Hepatitis B can spread through needles

What is Hepatitis B

Hepatitis B is a viral infection caused by the Hepatitis B virus (HBV), a highly contagious virus that damages the liver. Across the globe, hepatitis kills 1.3 million people yearly and it is the second biggest cause of death due to an infectious disease globally. About 83% of HPV-related deaths are attributed to Hepatitis B infection and 17% to hepatitis C infection.

Hepatitis B infection can be acute (short-lived) and resolve on its own in 6 months or less. Most hepatitis B infections in adults are acute. Hepatitis B infection is chronic when it lasts more than 6 months. About 90% of infants who are infected with Hepatitis B develop a chronic infection, compared to only 2-6% of adults.

Chronic infection can last a lifetime, and cause premature death due to liver failure, cirrhosis, or liver cancer. In the US, 850,000-2.2 million people are currently living with chronic hepatitis B infection. WHO estimates that 254 million people are living with chronic hepatitis B globally, with 1.2 million more getting infected every year.

How is Hepatitis B transmitted?

Hepatitis B is transmitted when fluids from the body of a person infected with Hepatitis B enter the body of an uninfected person. HBV is a hardy virus and can stay alive and infectious for at least a week outside the body. So dried blood of an infected person even in trace amounts too small to see can be a source of infection.

Hepatitis B is generally spread through:

  • Sexual contact by having vaginal or anal sex with an infected person
  • Sharing needles or syringes with an infected person
  • Sharing sex toys with an infected person
  • Sharing razors, toothbrushes, pierced jewelry, metal nail files or nail clippers, etc. which have fresh or dried blood of an infected person
  • Getting procedures done at piercing salons, tattoo parlors, nail salons, acupuncture locations, and dental offices that do not adequately sterilize their equipment
  • Through human bites or vigorous kissing through open skin on the mouth, such as due to tiny cracks, abrasions, or ulcers.
  • From a pregnant mother to her baby at birth (perinatal transmission)

HBV is not transmitted by hugging, shaking hands, eating meals prepared by infected persons, sneezing, coughing, or coming in contact with toilet seats or doorknobs used by infected persons.

In the US, data from 2018 indicate that the common method of transmission was shared syringes used during drug abuse. People battling drug addiction and homelessness are at high risk of getting infected by Hepatitis B.

The second most common method of transmission was having multiple sex partners. Men who have sex with men, and those who have ever had a sexually transmitted disease are at a greater risk of Hepatitis B infection.

Hepatitis B can transmit to baby during birth

Perinatal transmission of hepatitis B

Perinatal (mother-to-child) transmission accounts for about 25,000 Hepatitis B infections in newborns in the US yearly. About a quarter of infants die prematurely because of the infection, and 90% of those who survive develop chronic infection.

Medical intervention during pregnancy can prevent transmission to the child, and early medical treatment and vaccination of the newborn can prevent the infection from taking hold in the infant. Injections of hepatitis B immune globulin and single-dose hepatitis B vaccine within 12 hours of birth followed by a complete series of hepatitis B vaccination are 94% effective at preventing infection in infants born to HBV-positive mothers.

Globally, the lack of medical care for pregnant women and newborns is a significant source of widespread hepatitis B infection, especially in areas where it is widespread such as some countries in Africa, Asia, South America, and the Caribbean.

Symptoms of hepatitis B

Hepatitis B is often asymptomatic. It is common to not observe any symptoms in infected infants and children under 5 years of age. Adults with chronic hepatitis B may also be asymptomatic until permanent liver damage has taken place. Acute hepatitis B can be asymptomatic as well.

When present, the symptoms include:

  • Dark-colored urine
  • Clay-colored stools
  • Yellowing of the skin and whites of eyes
  • Fever
  • Extreme exhaustion
  • Pain in joints
  • Nausea or loss of appetite

How contagious is HBV?

Hepatitis B is a highly contagious disease.

HBV is more contagious than the immunodeficiency virus (HIV). This is because it can be 100 times more concentrated in the blood than HIV. The modes of transmission of the two viruses are also similar.

How long does HBV stay alive outside the body?

HBV can stay alive and infectious on surfaces outside the body for at least a week.

Does alcohol consumption affect the progression of hepatitis B?

Alcohol consumption affects the progression of hepatitis B in the following ways:

  • Alcohol consumption accelerates liver damage caused by HBV
  • Alcohol can allow HBV infection to persist and become chronic.

Prevention and treatment of Hepatitis B

There is currently no cure for hepatitis B.

Urgent injection of hepatitis B immune globulin given within 12 hours of first coming in contact with HBV can potentially prevent the development of the disease.

In established hepatitis, medical treatment with antivirals can help slow the damage the virus does to the body. However, permanent liver damage such as scarring that has already happened cannot be reversed by medication.

Hepatitis is preventable by vaccines. Hepatitis vaccines are safe and effective. In the US, it is standard practice to vaccinate newborns with the Hepatitis B vaccine within 24 hours of birth if they are over 2 kgs or 4.4 pounds in birth weight. The vaccine series takes 3 doses to complete. Most adults who did not get vaccinated for Hepatitis B as infants can get the vaccine as adults. Combination vaccines for both Hepatitis A and Hepatitis B can also be administered.

The information provided in our blog posts is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this blog.

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