Patients often ask: I heard that there is a long-acting interferon, just one shot a week, the effect is very good, is it really true? The first of these is the “long-acting interferon”. The first is the first of the two types of interferon used in the treatment of slow hepatitis B. The other is the imported long-acting interferon. The common interferon has been available since the last century and was the main drug used in the treatment of slow hepatitis B at that time. Since 2005, a new breed of interferon has emerged: pegylated interferon, also known as long-acting interferon. The price of long-acting interferon is much higher than that of ordinary interferon, about 1000 yuan a head. What are the benefits of this expensive product? First, let’s understand why pegylated interferon is called “long-acting” interferon. The molecular weight of ordinary interferon is small and easily cleared by the body’s metabolism, so the time to maintain the efficacy is relatively short, about 6-7 hours, 3 injections a week, in the days without the injection, the virus can not be effectively controlled. The pegylated interferon overcomes this problem. Compared with the ordinary interferon, the pegylated interferon has the addition of the biologically inactive pegylated macromolecule on it, which makes the molecular weight of the drug increase greatly and prolongs the residence time in the liver and blood, and the duration of action is extended accordingly, so it is also figuratively called long-acting interferon. At present, there are two types of long-acting interferon in China: one is called Pyroxin, which has the largest molecular weight of about 40KD and can maintain effective blood concentration for 1 week after one subcutaneous injection, so it is usually injected once a week; the other is called Pellagra, which has a molecular weight of 12KD and can maintain effective blood concentration for up to 5 days after one injection. The structural changes of long-acting interferon bring some unique features and advantages. Compared to regular interferon, long-acting interferon can maintain a stable blood concentration and exert a stable inhibitory pressure on viral replication, which significantly improves the efficiency of treatment. For example, some patients who have failed to be treated with regular interferon can be treated with long-acting interferon instead and achieve efficacy. Long-acting interferon also has significant advantages over nucleoside (acid) analogs, another class of antiviral agents. Simply put, long-acting interferon has a higher chance of converting “major triplets” to “minor triplets”, is stable, has a durable response after discontinuation, and has no resistance problems during treatment. The cost of long-acting interferon treatment is higher, so it is a better choice for patients who are financially well-off and have a higher desire for efficacy. In terms of efficacy, some studies have predicted better outcomes for patients with high enzyme and low toxicity prior to treatment, with a higher chance of converting “major triplets” to “minor triplets”. For example, in a large clinical study of Pyroxine, the HBeAg seroconversion rate at 24 weeks after discontinuation of Pyroxine for 48 weeks was over 60% for patients with ALT 5-10 times the upper limit of detection and HBV DNA <7log copies/m. In addition, for patients who do not wish to take medication for a long time, they can also try to receive long-acting interferon therapy first; young women of childbearing age who wish to be treated earlier to be able to have children are more sure of long-acting interferon.