Interferons are divided into regular interferons and long-acting interferons; regular interferons were created relatively early and long-acting interferons have been available only in the last 10 years. The so-called long-acting interferon is a molecule that is linked to a large molecule of ordinary interferon, which is usually a non-toxic, water-soluble, non-biologically active pegylated glycol molecule. Why is it necessary to link a polyethylene glycol molecule to a regular interferon? This is mainly because the molecular weight of regular interferon is very small and easily cleared by the body’s immune system, so it has some inherent defects: first of all, the half-life of regular interferon is very short, only 4 hours, which means that if the patient injects regular interferon, the next day the interferon is completely cleared from the body. Therefore, regular interferon has to be injected every other day, which is very inconvenient to use and often makes it impossible for patients to adhere to treatment. In particular, when the normal interferon is cleared from the body, the virus will start replicating again and cannot be suppressed for long. In addition, the molecular weight of regular interferon is very small, and it will diffuse through the capillaries in the tissues and be excreted through the kidneys, making the concentration of interferon in the liver low and not more efficient in inhibiting virus replication. Finally, this also results in greater adverse effects of regular interferon. By linking the pegylated glycol molecule, it is like tethering a large rock to the regular interferon, and the adult molecular weight becomes larger, which overcomes some of the disadvantages caused by the small molecular weight of regular interferon and enhances the effect of interferon. The actual fact is that you can find a number of advantages compared to ordinary interferon: 1. Anti-viral efficacy Long-acting interferon and ordinary interferon, like the dual role of anti-virus and regulation of immunity, but the effect is more excellent. Due to the large molecular weight, the time of circulation in the body is extended, the serum concentration is stable, while the main transport liver, the concentration in the liver is high, it is easy to maintain a stable effective therapeutic concentration, the antiviral effect is high. Some study results show that long-acting interferon treatment compared with ordinary interferon, HBeAg serological conversion rate increased nearly double. 2, less adverse reactions long-acting interferon adverse reactions and ordinary interferon, the same, common is the flu-like symptoms, transient peripheral blood cytopenia, and thyroid function impairment and some autoimmune reactions, but the incidence and severity are lower than ordinary interferon, most of them only need symptomatic treatment, no need to stop the drug. 3, only need to be subcutaneously injected once a week, the treatment is convenient Because of the characteristics of long-acting interferon molecular weight, it takes 50 hours after subcutaneous injection to absorb half, about 72 ~ 96 hours to rise to peak serum, after the injection of pegylated interferon alpha-2a, with therapeutic effect of blood concentration can be maintained for up to 168 hours, once a week, for 6 ~ 8 weeks after the drug can reach a stable Blood concentration, very convenient to use. 4, mainly distributed in the liver, can be a constant therapeutic dose, no need to adjust according to body weight Long-acting interferon is mainly perfused by the blood in the liver, rarely diffused to the surrounding tissue interstices, can then maintain a stable concentration in the liver. This is because weight has very little effect on the concentration of long-acting interferon in the liver, so that the doctor can use a constant therapeutic dose for the patient, eliminating the need to adjust the dose according to body weight, making the medication more convenient and effective.