There are many people suffering from hepatitis B in China. Hepatitis B major tri-positive is a common liver disease that not only brings greater harm to the patient himself, but also has a strong contagious effect, bringing harm to the patient’s family and friends. The actual fact is that a lot of people are worried that they will be as contagious as the big three. So, can small triplets be contagious? The common modes of transmission of hepatitis B minor third-positive are as follows: 1, blood transfusion, blood products The input of blood without formal testing and informal production of plasma, blood cells, globulin, albumin, clotting factors, etc., can cause blood transfusion, transfusion of blood products after hepatitis B or C. 2, unclean interventional medical devices stabbing injuries such as syringe needles, not sterilized for continuous multi-person use. Blood collection needles, acupuncture needles are not disinfected for continuous use, endoscopes such as colonoscopes are not disinfected for continuous use by multiple people, which can cause new transmission and new infections by exchanging the blood of multiple people through new wounds. 3, mother and child perinatal transmission This transmission is directly related to blood, hepatitis B virus surface antigen-positive pregnant women, especially e antigen-positive pregnant women, in the process of delivery is easy to pass the virus to the newborn baby. 4, sexual transmission This transmission belongs to body fluids plus blood. The semen of male surface antigen carriers and the vaginal secretions of women contain the hepatitis B virus, which can easily cause damage to the genital mucosa during sexual intercourse and cause infection. 5, intravenous drug users often a syringe we take turns injecting, blood exchange, the most likely to be infected with hepatitis B, C, especially hepatitis C transmission in the most serious intravenous drug users. 6, certain risk factors in life such as sharing razors, sharing toothbrushes, sharing towels, tattoos, eyebrow tattoos, ear piercing, nose piercing, ring auricles, etc., due to the uncleanliness of the knife caused by mutual transmission. Mosquito bites cannot cause transmission, shaking hands, kissing, sharing meals, working together, sharing meals and dormitories, there is no risk of infection.