Exploring 3 common types of viral hepatitis: hepatitis A, B, C

April 16, 2024 - New York University Langone Health defines hepatitis as an inflammation of the liver often caused by a viral infection, commonly hepatitis A, B, and C viruses. A recent report from the World Health Organization (WHO) reported that there are 3,500 daily deaths associated with viral hepatitis globally. Global hepatitis deaths increased from 1.1 million in 2019 to 1.3 million in 2022.

Nearly all viral hepatitis mortality is linked to hepatitis B and C, accounting for 83% and 17%, respectively. LifeSciencesIntelligence explores the three most common types of viral hepatitis, their symptoms, and available treatments and prevention protocols.

Hepatitis A 

Hepatitis A is one of the most easily resolvable viral hepatitis infections. Gastroenterology Research notes that there are 1.4 million cases of hepatitis A annually. The CDC estimates roughly 19,900 hepatitis A infections in the United States in 2020.  

The condition is definitively diagnosed through an enzyme immunoassay that detects serum immunoglobulin M (IgM) anti-hepatitis A viral antibodies. However, this type of diagnostic testing is time-consuming and costly. Instead of the standard immunoassay, more efforts have been allocated toward developing point-of-care testing to optimize diagnostics in resource-poor settings.

“A study in Brazil showed that a commercial rapid immunochromatographic test for HAV IgM had 81% sensitivity and 100% specificity. Another study on 5,438 patients in Puerto Rico demonstrated the efficacy of a rapid salivary test for HAV IgG, with sensitivity comparable to human plasma analyses,” noted researchers in Gastroenterology Research.

According to NYU Langone, most hepatitis A infections resolve on their own. The virus can be transmitted from person to person and through contaminated water and food. Additionally, the virus can be transmitted through unprotected sex.

Viral symptoms may not appear for weeks after a person has been infected, and some patients may remain asymptomatic; however, the most common symptoms of hepatitis A include fever, nausea, loss of appetite, diarrhea, and jaundice.

While most cases of hepatitis A are acute and resolve within a few weeks or, at most, a few months. According to NYU, some patients have secondary flare-ups after the initial symptomatic phase; however, they resolve for good after the second flare-up. An estimated 10–15% of individuals with hepatitis A will have relapsing hepatitis A.

While there are no approved therapies for hepatitis A, vaccination can effectively prevent the condition. Gastroenterology Research notes children one year old and older, travelers who are going to endemic regions, individuals with chronic liver disease, men who have sex with men (MSM), and illicit drug users should be vaccinated.

Since the invention of the hepatitis A vaccine, preventing hepatitis A has become more accessible. Patients are advised to get vaccinated before traveling to high-risk regions, including Central and South America, the Middle East, and Africa.

Additionally, they are advised to avoid commonly contaminated food from these countries, including fresh fruits and vegetables that can’t be peeled, raw shellfish, unpurified tap water, and ice cubes made from tap water.

To prevent hepatitis A, vaccines are recommended at one year or older; however, infants between 6 and 11 months can receive a two-dose vaccine series if they are traveling outside of the US. Those who receive a two-dose series should get another dose at one year or older.

An additional tool for preventing hepatitis A is suspected or post-exposure prophylaxis with a vaccine and immune globulin for most individuals; however, immune globulin alone is recommended for individuals over 40, children under one year, and immunocompromised individuals.

Hepatitis B

Hepatitis B is another common form of hepatitis, characterized by jaundice, loss of appetite, nausea, vomiting, abdominal pain, and joint pain. However, some patients with hepatitis B are asymptomatic, which may contribute to the approximately two-thirds of people who are infected but do not know they have the disease.

Hepatitis B can be diagnosed with serologic testing that detects the presence of IgM antibodies to hepatitis B core antigens.

The condition can be acute or chronic if the infection lasts six months or longer. The CDC estimates that there were 13,300 new hepatitis B infections in the US in 2021, and 640,000 adults in the US are living with chronic hepatitis.

The average, healthy adult can fight off a hepatitis B infection within a few months, mitigating permanent liver damage; however, chronic iterations of the disease can result in permanent liver damage and, in some cases, liver cancer. According to the CDC,this viral infection is transmitted via contact with bodily fluids, including blood, saliva, and semen. Individuals can also contract the virus upon contact with a contaminated object.

Additionally, hepatitis B can be transmitted from a mother to their newborn during childbirth. Providers can start by assessing a mother’s viral load to mitigate the risk of viral transmission. Lower viral loads, which correlate with a lower risk of transmission during childbirth, can be achieved with antiviral therapy during the third trimester of pregnancy. Infants born to mothers with hepatitis B should be vaccinated within 12 hours of birth and receive hepatitis B immune globulin to prevent infection.

Because of the viral transmission methods, certain factors, including using injectable drugs and having unprotected sex, can increase the risk of hepatitis B.

Hepatitis B vaccines are also recommended for all infants within 24 hours of birth. Individuals under 19, adults between 19 and 59, and adults over 60 with risk factors for hepatitis B who have not been adequately vaccinated are also eligible.

Hepatitis C

Hepatitis C is another highly contagious and common form of viral hepatitis. According to NYU Langone Health, patients with hepatitis C can be asymptomatic for years or decades, contributing to unknown disease spread and the roughly 40% of people with the condition who do not know they are infected.

In 2021, the US identified approximately 69,800 new cases of hepatitis C in the US, contributing to the roughly 2.2 million adults living with the condition.

The virus is associated with severe and permanent liver damage that can occur even if patients are asymptomatic. Untreated hepatitis C has been linked to cirrhosis and liver cancer. The condition is one of the leading causes of liver transplants and liver cancer in the US.

Much like hepatitis B, hepatitis C is transmitted through contact with bodily fluids, most commonly contact with contaminated blood. The CDC cites needle sharing as one of the most common forms of hepatitis C viral transmission in the US. Other factors that may increase the risk of contracting hepatitis C include having unregulated tattoos or piercings and a history of blood transfusion before 1992.

While there is no available vaccine for hepatitis C, the condition can typically be treated with antiviral therapies, including sofosbuvir and daclatasvir.

Continued efforts in vaccination, early diagnosis, and access to treatment are crucial in the ongoing battle against viral hepatitis. These efforts aim to save lives and alleviate the socioeconomic burden associated with these infections.

Through concerted collaborative efforts and the implementation of comprehensive public health interventions, the substantial threat posed by viral hepatitis to global health could be effectively mitigated.