Compared with most other communicable diseases, hepatitis has risen in global importance since the 1990s. It is now a leading cause of death and disability worldwide and kills at least as many people as tuberculosis, HIV/AIDS, or malaria.
This is the main finding of an international study - led by Imperial College London in the United Kingdom and the University of Washington in Seattle - published in The Lancet.
The study - which analyzes data from 1990-2013 on 183 countries - is timely, as the World Health Organization (WHO) launch a major new effort to tackle viral hepatitis.
The findings should prove of "crucial importance to global health policy," note the authors.
Hepatitis means inflammation of the liver, an important organ that processes nutrients, filters the blood, and fights infections. If the liver becomes damaged or inflamed, then these functions are impaired.
While heavy use of alcohol, toxins, some drugs, and certain medical conditions can cause hepatitis, it is most often caused by a virus, of which there are five types: A, B, C, D, and E.
Hepatitis is mostly spread through contact with bodily fluids, except for types A and E, which spread through food or drink contaminated with feces. In the United States, the most common types of viral hepatitis are A, B, and C.
Most deaths worldwide due to hepatitis are due to types B and C, which cause liver damage (cirrhosis) and liver cancer. Symptoms of these infections include fatigue, jaundice (yellowing of the skin), and nausea. However, some infected people do not have symptoms, and they may not find out they have hepatitis until they develop serious complications.
Deaths from viral hepatitis up 63 percent
For their study, the researchers analyzed data from the WHO Global Burden of Disease (GBD) Study.
They assessed deaths from hepatitis A, B, C, and E (hepatitis D only infects people who already have type B).
They found that annual deaths from acute infection, cirrhosis, and liver disease caused by viral hepatitis worldwide went up from 890,000 in 1990 to 1.45 million in 2013 - an overall increase of 63 percent.
The finding puts viral hepatitis on a par with the world's leading infectious diseases. In 2013, for example, 1.3 million people worldwide died from AIDS, 1.4 million from tuberculosis (TB), and 855,000 from malaria, note the authors.
Corresponding author Dr. Graham Cooke, from the Faculty of Medicine at Imperial, describes the finding as "startling" because global deaths from other leading infectious diseases - such as TB and malaria - have dropped since 1990.
The team also discovered that deaths from viral hepatitis were higher in high- and middle-income countries than lower income countries and that the overall burden of the disease is now more evenly divided between rich and poor nations.
The analysis reveals that most deaths to viral hepatitis occurred in East Asia, and that types B and C accounted for the majority of deaths globally.
Dr. Cooke speculates that one reason why B and C are the most deadly of the hepatitis viruses could be because they cause long-term infections with few immediate symptoms. Thus, affected individuals carry on unaware until a more serious condition emerges, such as serious liver damage or cancer.
And, while an effective vaccine for hepatitis B has been available for a while, much of the world is not vaccinated. Plus, "there is no similar vaccine for hepatitis C," Dr. Cooke adds.
Funding structures need to change to deal with hepatitis
The researchers also calculated that in 2013, years of life lost to hepatitis exceeded 41 million. Plus, they found that the total number of years in which people lived with disabilities due to hepatitis was over 870,000 years.
Years of life lost is a measure of premature mortality due to a disease. It is an estimate of the average years that people who died prematurely from hepatitis would have lived had they not developed the disease.
The researchers conclude that "an evolution in funding structures is required to accommodate the burden of viral hepatitis and allow effective responses in low-income and lower-middle-income countries."
Dr. Cooke explains that while there are effective treatments and vaccines for viral hepatitis, shortage of money means they do not reach the patients that need them - especially when you compare the situation to that of TB, HIV/AIDS, and malaria.
He says we now need to implement the global action plan for hepatitis, which the World Health Assembly approved in May.
"This study will hopefully highlight that we should be doing more to make treatments for viral hepatitis affordable and accessible."
Dr. Graham Cooke