Hepatitis B virus is not transmitted through the respiratory and digestive tracts, chronic hepatitis B patients or hepatitis B virus carriers can apply for a health certificate as long as their liver function is normal, regardless of whether the virus is replicating or not and whether the level of HBV-DNA is high. Not only can you apply for a health certificate, but you can also engage in the catering industry. Hepatitis B virus is mainly transmitted through blood, sexual transmission, medical transmission, mother-to-child transmission, and transmission through broken skin mucous membrane. If you have a pedicure, tattoo, earring piercing, razor or toothbrush sharing, you can also transmit the hepatitis B virus. General contact with hepatitis B virus is not infectious, such as kissing, hugging, eating together in a restaurant, sharing a tableware, and if there is no blood exposure, hepatitis B virus will not be transmitted. Therefore, hepatitis B carriers or hepatitis B patients, as long as the liver function is normal, can apply for a health certificate.