How can we prevent a "head-on confrontation" with a Delta mutant?

When it comes to the global COVID-19 epidemic, "Delta" is a key word. At present delta mutation poison strain already spread 92 countries, the guangzhou of our country, shenzhen, dongguan also had been with "delta" frontal battle. How to recognize this mutant strain? What challenges does it pose to global epidemic prevention and control? What should we do about it? "News 1+1" tonight, connected to the Chinese Center for Disease Control and Prevention researcher Feng Zijian, common concern: "Delta" mutant strain, how to prevent?

For two days in a row, no new cases were reported in Guangdong, indicating that the epidemic is nearing an end.

Feng zijian, a researcher with the Chinese center for disease control and prevention, said the epidemic in guangdong includes guangzhou, shenzhen and dongguan.

There have been no new cases of the "May 21" epidemic in Guangzhou for many days. I think the transmission should have been stopped. I can say with a high degree of confidence that the epidemic in Guangzhou is nearing an end.

Shenzhen "5.21" epidemic. It has been more than two weeks since the outbreak in Yantian Port of Shenzhen occurred without any new cases. Its transmission should be stopped and the outbreak has been extinguished.

Shenzhen Dongguan "6.14" epidemic. We also focus on recently should be caused by the outbreak of this round of small-scale entry flight in shenzhen, now there are no new cases for two days, we still need to continue to observe, response and disposal of the outbreak, but shenzhen found faster, are more forceful action, so I believe it will be quickly control the outbreak.

How to understand that the source of infection in Shenzhen and Guangzhou is a delta variant strain with different sequences?

On the CA868 flight from South Africa to Shenzhen, more than 30 infected people were infected with different viruses in different places. Such differences led to slight differences in their re-transmission after their entry. Therefore, the Delta variant strains with different sequences do not mean that this is the Delta + variant virus.

How do you view the shortest 14-second transmission cases in Guangzhou?

Fourteen seconds is not a measure of how fast a disease can spread. For example, if there is an effective contact between an infected person and a susceptible person, for example, the infected person sneezes or coughs and spatters respiratory droplets carrying the virus close to the susceptible person, it can instantly infect another person. In addition to the "delta" mutant strains spread the characteristics of fast speed, it is mainly refers to from effective exposure and infection to the speed of clinical symptoms, pathogenesis, onset time was shorter, or is it between each generation, intergenerational transmission interval relative to the last pandemic strain, the average incubation period shortened for a day or two, some faster correspondingly.

What is the pathogenicity of the delta variant virus?

In India and Britain, Delta appears to have become more pathogenic, meaning that the proportion of people infected with symptoms has increased. In guangdong this dial outbreak, more than 150 people in more than 108 cases are all the symptoms, the proportion compared with our previous outbreak a few times, and not only in our country, also is not only the outbreak in guangzhou, in other countries, including Britain, India also can be seen, the proportion of teenagers infections seem to rise.

Are the clinical symptoms different when infected with the delta variant strain?

Above all in the clinical manifestation, "Delta" the clinical manifestation of the virus and the clinical symptoms caused by the previous strain, there is no significant difference, or in the past we are familiar with some infections, such as fever, dry cough, fatigue and so on. In terms of personal protection, although the virus has become more transmissible, the existing public health measures, including personal prevention measures, are still effective, but what we need to do now is to further improve the timeliness and intensity of the measures.

How effective is our country vaccine to delta mutation strain?

The existing vaccines in China still have considerable effectiveness against this virus, but the protective effect has also been reduced. On the one hand, many countries are using the neutralizing antibodies of the current vaccine to neutralize the "Delta" mutant strain, and there are also some reports abroad that the neutralizing effect has been reduced, some reports are 3 times, some are 4 times, or more. Protective indicators, a few percent to 10 percent reduction. For example, with the mRNA virus, the protection seems to go down from the high 90s to the low 80s. The neutralization efficacy ratio of the neutralizing antibodies for the two inactivated vaccines in our country also found that the neutralization efficacy decreased, but it is still protective. For example, in the Guangdong epidemic, we can see a very obvious phenomenon, is that all the infected people who have been vaccinated, did not develop severe disease. In other words, those infected people who have been vaccinated, did not get vaccinated, so our vaccine is very effective in preventing severe disease.

Will the Delta variant take over from the previous pandemic strain, Novel Coronavirus, as the major global pandemic strain?

Very likely. Especially the mutation strain it enhancement is conducive to ability and the spread of infectious virus survival, is conducive to the spread of the virus, so the next phase may be more and more widely, the scope of its spread "delta" mutant strains are likely to become more countries and regions in the world in the next stage of epidemic spread of the pandemic strain.

Why does novel coronavirus mutate?

This is a characteristic of the virus itself. It belongs to mRNA virus, which itself is prone to genetic mutation. In addition, from the perspective of the evolution and ecology of the whole virus, it is also a selective evolution of the virus. It can always select some characteristics that are beneficial to its survival and reproduction, and retain them after mutation.

How can we be "a foot higher" in response to the Delta mutant strain?

Stricter enforcement of measures. On the one hand, at a time when the vaccine has not established a very effective population immunity barrier, we still need to stick to the existing public health and social prevention and control measures, and these measures need to be more strictly implemented.

Accelerate vaccination. The other thing that is very important is that we have to speed up the vaccination, we have to speed up the coverage of the vaccine, which will also have the effect of suppressing the transmission of the virus, which will also have the effect of preventing the mutation of the virus.

Efforts to improve vaccines against mutated strains have continued.

The World Health Organization (WHO), as well as China's vaccine research and development enterprises and research institutions, are promoting the research and development of novel coronavirus mutant vaccine. There are mainly two routes:

Production of a second generation vaccine. The second-generation vaccine is supposed to produce a vaccine that can deal with a variety of mutated strains so that the virus doesn't escape, but the route of research is complex and the timing of development is highly uncertain.

To produce an improved vaccine. The idea is to add or replace the old vaccine, the existing vaccine, with a new mutant strain of the virus and its genetic sequence. Once these vaccines are developed, they can be re-administered with existing vaccines, or they can be used to boost immunity, including re-vaccination, with a new and improved vaccine and a vaccine with a different strain.

We must not relent in our "head-to-head" confrontation with the delta variant.

Since March and April last year, China has emphasized the normal epidemic prevention and control work, adhering to the implementation of the "import of external prevention, domestic prevention and control rebound" strategy, such a strict prevention and control has lasted for more than a year. As time goes by, there may be some slack, fatigue and tiredness in the prevention and control work. This is something we need to overcome. We must remain on high alert and work in a very good state to prevent the spread of the epidemic.