HBV infection is prevalent worldwide, but the intensity of HBV infection varies greatly from region to region. According to the World Health Organization, about 2 billion people worldwide have been infected with HBV, 350 million of whom are chronically HBV-infected, and about 1 million people die each year from liver failure, cirrhosis and primary hepatocellular carcinoma (HCC) caused by HBV infection. HBV is a blood-borne disease and is mainly transmitted via blood (e.g. unsafe injections, etc.), mother-to-child and sexual contact. Due to strict HBsAg screening of blood donors, HBV infection caused by blood transfusion or blood products has been less frequent; transmission through broken skin and mucous membranes is mainly due to the use of medical devices that have not been strictly sterilized, invasive diagnostic and surgical operations, unsafe injections, especially drug injection; other things such as pedicure, tattoo, earring piercing, accidental exposure of medical personnel at work, sharing razors and toothbrushes, etc. can also be transmitted. Other factors, such as foot trimming, tattooing, earring piercing, accidental exposure of medical personnel at work, sharing of razors and toothbrushes, etc. can also be transmitted. Mother-to-child transmission occurs mainly during the perinatal (labor) period, mostly from exposure to the blood and body fluids of HBV-positive mothers during delivery, and has been greatly reduced with the use of hepatitis B vaccine combined with hepatitis B immunoglobulin. The risk of HBV infection increases with unprotected sexual contact with HBV-positive people, especially those with multiple sexual partners. Epidemiological and experimental studies have not found that HBV can be transmitted by blood-sucking insects (mosquitoes, bedbugs, etc.).