NIAID supports and conducts research on each of the five known hepatitis viruses—A, B, C, D and E. During the past 60 years, NIAID-supported investigators have been involved in many important breakthroughs in hepatitis research, including the discovery of the hepatitis A and E viruses, the development of one of the first diagnostic tests for hepatitis A, and studies that led to the creation of the hepatitis A vaccine and laid the foundation for advanced development of a hepatitis E vaccine. In addition to basic research to understand the molecular processes of hepatitis infection, our research involves significant focus on the development of new treatments and vaccines to prevent acute and chronic hepatitis infection.
Although vaccine-preventable, hepatitis B-induced liver cirrhosis and liver cancer kill about 3,000 people in the United States and roughly 620,000 people worldwide each year. The virus can be spread from mother to child during childbirth; through sex with an infected partner; through contact with the blood of an infected person and by sharing needles, syringes, razors or toothbrushes with an infected person. Co-infection with hepatitis B and HIV is common.
NIAID is working with researchers in academia and the pharmaceutical industry to screen hundreds of new drug compounds for potential antiviral activity against hepatitis B. The goal is to find new treatments that will work alone or in combination with current drugs to reduce or resolve chronic infections. For example, one candidate drug has shown promise in transgenic mice and is now being evaluated in rats.
Hepatitis C is primarily spread through contact with the blood of an infected individual, such as through needle-sharing practices of injection drug users, unsafe injection practices in healthcare facilities, mother-to-child transmission during childbirth, and infrequently, through sexual contact with an infected partner. Currently available drugs cure only a proportion of treated individuals, but new drugs in trials may significantly improve treatment success rates. There is no vaccine to prevent hepatitis C.
In March, NIAID-supported researchers began a Phase I/II clinical trial of a promising candidate vaccine to evaluate its safety, tolerability and protective ability against hepatitis C. NIAID is supporting several studies, including research at five Hepatitis C Cooperative Research Centers across the country, that focus on the immune response to infection and how treatment might strengthen this response. Additionally, NIAID researchers have conducted preclinical work on several candidate antivirals targeting hepatitis C and are developing biomarkers for predicting progression to hepatitis C-associated liver cancer and HIV co-infection.
Spread via contact with contaminated water or food, hepatitis E is rare in the United States but prevalent in south and central Asia, sub-Saharan Africa and the Middle East.
Studies have found that in certain regions, when pregnant women are infected with hepatitis E virus during the second or third trimester, their babies are at increased risk of poor health and birth defects. NIAID-funded researchers are testing the hypothesis that mothers with micronutrient deficiencies are more likely to experience this effect and what potentially could be done to prevent it. Other NIAID-supported scientists are studying whether hepatitis E virus can become reactivated after a bout of acute disease. Successful trials of hepatitis E vaccines have also taken place, but none have yet been licensed for use in the United States. In 2012, NIAID co-hosted a research workshop, “Hepatitis E in the United States,” with the goal of increasing awareness of the virus among clinicians.