The outbreak of the COVID-19 epidemic has dealt a heavy blow to the global economy. Because of its strong transmission and variability, COVID-19 can spread rapidly around the world, in order to control the epidemic as soon as possible, revive the economy and resume work as soon as possible. Up to now, more than 23 million COVID-19 patients have been diagnosed in the world, and the cumulative death cases have exceeded 8 1.4 million. Although the epidemic has been controlled, countries dare not relax their vigilance. What worries people all over the world is not the relapse patients, but the secondary infection.

I. What secondary infection and WHO's response A 33-year-old Hong Kong man was diagnosed again, which attracted global attention. The team from the Department of Microbiology of the University of Hong Kong compared the gene sequencing of the first and second infected virus strains and found 24 differences. The gene sequencing of the two infected virus strains was obviously different, and no antibody was detected in their bodies, so it was judged that they were reinfected after recovery, not? Recurrent positive patients? And it is likely to infect others again. For the emergence of secondary infection, WHO spokesperson Margaret? Harris said that this is not common, otherwise it will be more. What matters is what this case means to the immune response. At present, many studies are tracking and measuring the antibody level in human body to understand the duration of natural immune protection.

Second, will the vaccine fail? Many people are generally worried about the effectiveness and durability of COVID-19 vaccine, and WHO's statement that secondary infection in COVID-19 is not common. Relevant experts said that the research team is still isolating and cultivating the second infected virus, and the infectivity of the virus has not yet been determined. Therefore, the specific impact of this case on vaccination in COVID-19 needs further study. Some experts also said that even if the vaccine needs to be updated, it is not difficult to achieve it technically, and there is no need for excessive panic. The mutation of COVID-19 is not as fast as that of influenza virus.

Third, self-protection before the epidemic. There are secondary infections all over the world, and the safety of COVID-19 vaccine has not been fully guaranteed, so we should do a good job of self-protection. Go to crowded places as little as possible and wear masks when going out; Develop the habit of washing hands frequently, taking more body temperature and ventilation in the house; During the period of home isolation, we should also maintain proper exercise and enhance our resistance. Protecting yourself is actually contributing to the prevention and control of the epidemic.