HBV is a blood-borne disease and is mainly transmitted through blood (e.g. unsafe injections), 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 injections; others such as pedicure, tattoo, earring piercing, accidental exposure of medical personnel at work, sharing razors and toothbrushes Other factors such as foot massage, tattooing, earring piercing, accidental exposure of medical personnel at work, sharing of razors and toothbrushes can also be transmitted. Mother-to-child transmission mainly occurs during the perinatal (labor) period, mostly from contact with the blood and body fluids of HBV-positive mothers during delivery, but with the application of hepatitis B vaccine combined with hepatitis B immunoglobulin, mother-to-child transmission has been greatly reduced. The risk of HBV infection increases with unprotected sexual contact with HBV-positive persons, 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.).