Viral hepatitis spreads through two main routes depending on the type: contaminated food and water (hepatitis A and E) or contact with infected blood and body fluids (hepatitis B, C, and D). Each type of hepatitis virus enters the body differently, and understanding those differences is key to knowing your actual risk.
Hepatitis A: Contaminated Food and Water
Hepatitis A spreads through what’s called the fecal-oral route. You get it by swallowing something, usually food or water, that’s been contaminated with feces from an infected person. That sounds extreme, but it takes only a microscopic amount. An infected food handler who doesn’t wash their hands thoroughly after using the bathroom can transfer the virus to anything they touch.
Specific foods have been linked to major outbreaks in the U.S. over the past decade. Fresh and frozen strawberries have caused repeated multistate outbreaks, including cases linked to imported organic strawberries in both 2022 and 2023. Pomegranate seeds imported from Turkey caused 165 infections in 2013. Raw scallops triggered an outbreak in Hawaii in 2016, and fresh blackberries were linked to 20 cases in 2019. The common thread is produce handled by infected workers or irrigated with contaminated water, and shellfish harvested from polluted waters.
You can also catch hepatitis A through direct contact with someone who’s infected, including through oral-anal sexual contact. Waterborne outbreaks happen too, typically from sewage-contaminated or poorly treated drinking water, though these are less common in countries with modern water infrastructure.
Hepatitis B: Blood, Sex, and Childbirth
Hepatitis B is a bloodborne virus, but it’s far more contagious than most people realize. It spreads through contact with infected blood, semen, vaginal fluids, saliva, and menstrual blood. The most common transmission routes worldwide are from mother to child during birth, through unprotected sex with an infected partner, and through shared or reused needles.
Mother-to-child transmission is especially efficient. When a pregnant woman carries high levels of the virus, the risk of passing it to her baby during delivery is 70 to 90 percent without preventive treatment. Even mothers with lower viral activity still transmit the infection in roughly 12 to 25 percent of cases.
Hepatitis B is remarkably tough outside the body. The virus can survive on surfaces at room temperature for at least seven days, which means dried blood on a razor, toothbrush, or nail clipper can still be infectious days later. A single needlestick from a contaminated needle carries a 37 to 62 percent chance of infection, making it far more transmissible per exposure than HIV (0.3 percent) or hepatitis C (1.8 percent).
Other documented routes include tattooing and body piercing with non-sterile equipment, sharing drug injection supplies, and accidental exposure in healthcare settings. Before routine blood screening, transfusions were a significant source; today, donated blood is tested for hepatitis B in most countries.
Hepatitis C: Primarily Through Blood
Hepatitis C spreads almost exclusively through blood-to-blood contact. The single biggest risk factor today is sharing needles or other equipment used to inject drugs. Even items like cookers, cotton filters, and water used to prepare drugs can carry the virus.
Around 50 million people worldwide have chronic hepatitis C, with about 1 million new infections each year. Roughly 242,000 people died from the disease in 2022, mostly from liver cirrhosis and liver cancer that developed over years of undetected infection.
Like hepatitis B, the virus can linger on surfaces. Research published in The Journal of Infectious Diseases found that hepatitis C remained infectious on dry surfaces at room temperature for up to six weeks. This has implications for any situation where someone might contact another person’s dried blood: shared razors, toothbrushes, nail clippers, or unsterilized tattoo and piercing equipment.
Sexual transmission of hepatitis C is possible but much less common than with hepatitis B. The risk increases with practices that involve blood exposure, such as rough sex or sex during menstruation. Mother-to-child transmission occurs in about 4 to 8 percent of pregnancies where the mother is infected, far lower than the rates seen with hepatitis B.
Hepatitis D: Only With Hepatitis B
Hepatitis D is unusual because it can only infect people who already have hepatitis B. The virus is incomplete on its own and needs the hepatitis B virus’s outer shell to replicate. You can catch both viruses at the same time (co-infection) or acquire hepatitis D after already having hepatitis B (superinfection). The transmission routes are the same as hepatitis B: infected blood, sexual contact, and shared needles. Preventing hepatitis B through vaccination effectively eliminates the risk of hepatitis D as well.
Hepatitis E: Similar to A, With a Twist
Hepatitis E spreads through contaminated water and food, much like hepatitis A. In developing regions, large outbreaks are typically tied to water supplies contaminated with sewage. In higher-income countries, hepatitis E also spreads through undercooked pork and wild game, particularly deer and boar. This animal reservoir makes hepatitis E somewhat unique among the hepatitis viruses. Person-to-person spread is less common than with hepatitis A.
How Quickly Symptoms Appear
Symptoms of acute viral hepatitis, when they show up at all, can appear anywhere from 2 weeks to 6 months after exposure depending on the type. Many people with viral hepatitis never develop noticeable symptoms during the early phase. This is particularly true for hepatitis B and C, where infections can remain silent for years or even decades while gradually damaging the liver. By the time symptoms like fatigue, yellowing of the skin, dark urine, or abdominal pain appear, significant liver damage may already be underway.
This long silent period is one reason hepatitis C remains so underdiagnosed globally. Of the estimated 50 million people living with chronic hepatitis C in 2022, only about 36 percent knew they were infected.
Who Faces the Highest Risk
Your risk depends heavily on which type of hepatitis you’re talking about. For hepatitis A and E, the biggest risk factors are traveling to regions with poor sanitation, eating raw or undercooked shellfish, and consuming imported produce that may have been handled or irrigated under unsafe conditions.
For hepatitis B and C, higher-risk groups include people who inject drugs, healthcare workers exposed to needlesticks, sexual partners of infected individuals, people who received blood transfusions before routine screening (early 1990s for hepatitis C), and infants born to infected mothers. Getting tattoos or piercings in unregulated settings also raises the risk, since non-sterile needles and ink can carry both viruses.
Vaccines exist for hepatitis A and B, and the hepatitis B vaccine also protects against hepatitis D. There is no vaccine for hepatitis C, making avoidance of blood-to-blood contact the primary prevention strategy. For hepatitis A, basic food safety measures matter: washing hands thoroughly after using the bathroom and before preparing food, drinking treated water when traveling, and being cautious with raw shellfish and imported berries or other produce linked to past outbreaks.