The key to the treatment of chronic hepatitis B is antiviral therapy. Although antiviral treatment for chronic hepatitis B has become increasingly standardized and improved, some patients may face special circumstances due to the large individual differences in this complex disease, and their treatment is also somewhat unique. For example, antiviral treatment during pregnancy and delivery, treatment of combined hepatitis C, and treatment of patients with different transaminase levels are some of the more common special cases. This article gives a brief introduction to the antiviral treatment in this situation. Xu Jie, Department of Infectious Diseases, Peking University Third Hospital What should I do if I have an unplanned pregnancy during anti-hepatitis B virus treatment? Women who become pregnant during anti-hepatitis B virus treatment should be treated differently depending on the antiviral drugs they are using. If interferon (including regular interferon IFNα and pegylated interferon Peg-IFNα) is used at the time of pregnancy, the pregnancy should be terminated promptly because of its anti-proliferative effect and pregnancy toxicity. If lamivudine and other pregnancy grade B drugs (telbivudine or tenofovir) are used, antiviral therapy can be continued after fully understanding the benefits and risks associated with continued use of the drug and weighing the pros and cons. As for termination of pregnancy, consultation with a specialist is recommended for specific cases. What should I do if I have a hepatitis attack during pregnancy with hepatitis B? During pregnancy, due to the increased burden on the liver, hepatitis B patients may experience hepatitis flare-ups and the decision to give antiviral treatment should be based on the severity of their disease. Pregnant patients with only mildly elevated liver function (ALT) can see a specialist to analyze the cause of the ALT elevation and decide whether to apply medication. Pregnant patients with severe liver disease may be considered for hepatoprotective drugs or antiviral therapy after fully understanding the benefits and risks associated with the use of drugs and weighing the pros and cons. Consultation with a specialist is required to determine whether to terminate the pregnancy. Antiviral drugs may be lamivudine or other pregnancy class B drugs (telbivudine or tenofovir), but not interferon or other pregnancy class C drugs (adefovir or entecavir). What about patients with hepatitis B combined with hepatitis C? According to statistics, some patients with chronic hepatitis B are also co-infected with hepatitis C virus, and co-infection with hepatitis B virus and hepatitis C virus can increase the incidence of severe liver disease, cirrhosis, liver function loss and hepatocellular carcinoma in patients. So, should hepatitis B patients with co-infection with hepatitis C be treated for hepatitis B or hepatitis C first? In fact, there is an interaction between the two co-infected viruses, mostly manifested as an inhibitory effect of hepatitis C virus infection on hepatitis B virus infection. In such patients, the HBV-DNA load, HCV-RNA load and liver function (ALT) should be combined to determine which viral infection is predominant, and then decide how to treat it. If a patient has HBV-DNA ≥ 104 copies/ml, along with an ALT greater than 2 times normal, and undetectable HCV-RNA, the hepatitis B virus infection should be treated first. Those with high HBV-DNA levels, ALT >2 times normal and detectable HCV-RNA should first be treated with standard doses of pegylated interferon (Peg-IFN) and ribavirin for 3 months, and if there is no response, add nucleoside analogs (lamivudine, entecavir, tenofovir or adefovir) to the treatment. This is because interferon has both anti-hepatitis C virus and hepatitis B virus effects, and may achieve inhibition and clearance of hepatitis B virus while treating hepatitis C. If, after standardized treatment with interferon to control hepatitis C, there are still manifestations of hepatitis B activity (e.g., positive HBV-DNA and abnormal ALT), nucleoside analogs may be used again to treat hepatitis B. Must all hepatitis B patients with normal or mildly elevated transaminases not need antiviral therapy? Some patients with chronic hepatitis B repeatedly test positive for HBV-DNA, but their transaminases are never significantly elevated. They seek medical help but are told that they don’t need antiviral treatment, but they are still upset when their HBV-DNA continues to “fly red”. Do you need antiviral treatment for this condition? There are two types of patients that we should pay attention to and recommend liver biopsy if necessary to clarify the indications for antiviral treatment. ① Patients with HBV-DNA load and mildly elevated ALT (between 1-2 times the upper limit of normal). These patients should first be excluded from other possible causes of mild ALT elevation, such as the presence of hepatitis C virus co-infection and other non-infectious fatty liver disease (including alcoholic liver disease, fatty liver, autoimmune liver disease, etc.). Secondly, liver biopsy is recommended in such patients, and on the basis of liver pathology a distinction can be made between patients with HBV infection in the immune tolerance phase and those with chronic hepatitis B with mild symptoms. The former is characterized by HBeAg positivity, high level of HBV replication, normal or low level of transaminases, and no significant inflammatory necrosis and fibrosis in their liver pathology. In this case, antiviral therapy is not only ineffective, but also prone to induce drug-resistant mutations of the virus, so it is recommended to withhold treatment and follow up regularly. In the latter case, liver pathological examination shows the presence of more pronounced inflammatory necrosis and/or fibrosis (Knodell HAI score ≥4 or ≥G2) and it is recommended that antiviral therapy should be administered. Monotherapy with a nucleoside analogue with a high resistance barrier (e.g. entecavir or tenofovir) or a combination of two drugs without cross-resistance (e.g. lamivudine or telbivudine in combination with adefovir) is recommended. ② Patients with normal ALT and age >45 years, especially those with a family history of hepatocellular carcinoma. Such patients, especially those with a high HBV-DNA load (>105 copies/ml), should be actively advised to have a liver tissue biopsy. Antiviral therapy is indicated if liver pathology shows moderate or more inflammation, necrosis and/or fibrosis (≥ G2/S2). If liver inflammation, necrosis and fibrosis are mild (