Why are epidemics emerging one after another?

The reasons for the endless epidemic are: COVID-19 is more contagious, COVID-19 is fearless of the climate, the mortality rate is low, and the vaccines at this stage are not so easy to use.

First of all, COVID-19 is more contagious.

The symptoms of SARS and COVID-19 are similar, with fever, high fever and cough. However, SARS is less contagious in the incubation period, while COVID-19 is equally contagious in the incubation period. And with the constant variation of the virus, when we found a patient in COVID-19, COVID-19 had even spread in the community for a long time.

And the current traffic is different from that in 2003. The flow of people between provinces has become more frequent, which also makes the virus spread faster.

Second, COVID-19 is not afraid of the climate.

Why SARS suddenly disappeared is still inconclusive. However, it is generally believed that the disappearance of SARS is related to climate. Sars is not resistant to high temperature. When the climate gets warmer, the spread of SARS is greatly limited. Can't even capture tropical countries.

But COVID-19 is different. Maybe COVID-19 was a little afraid of high temperature at first. However, Omicron originated in hot South Africa. Whether the warming weather really has no influence on COVID-19 now, COVID-19 is fearless now.

Third, the mortality rate is low.

Although COVID-19 is better than SARS in adaptability and transmission, COVID-19 is not as good as SARS in mortality. But this is not a good thing. It is precisely because of the high mortality rate of SARS that when SARS broke out, everyone was heavily guarded and took more precautions. As a result, SARS was strangled in the cradle and did not spread on a large scale.

COVID-19's mortality rate is not as good as that of SARS, although China is closely guarding against SARS, and reminds all countries in the world early that we must be careful about it. However, due to the mortality rate, they did not take this seriously. Even now, in 2022, they are still making a fuss about the mortality rate and taking a peaceful and laissez-faire attitude towards COVID-19. As a result, the situation in COVID-19 is getting worse and worse.

Fourth, the vaccine at this stage is not so easy to use.

The best way to deal with this virus is to vaccinate, but what is frustrating is that COVID-19 is so widely spread and mutates very frequently, so it can be said that a new wave will appear every few months. At first, the current vaccine can't 100% prevent infection.

Secondly, the current vaccine is lagging behind, Delta is contagious, and a vaccine to prevent Delta has been developed, but when the vaccine was successfully developed, the virus has mutated into Omicron.