In order to fully understand this problem, we need to know how the immune system works. The function of the immune system is to protect you from getting sick. Once your body is infected by a foreign virus, it will act immediately. In order to resist intruders, your body will release chemicals and white blood cells. They will produce specific antibodies, which will combine with the virus to prevent the virus from entering the protein of cells, and the body will make a special attack on T cells infected by the virus, thus reaching the first layer of human natural immunity.

Suppose you are infected with a new virus like COVID-19, it takes your body longer to respond, but once your body produces special antibodies, when you are infected with the disease again, they will take immediate action to kill the original virus. Scientists apply the same principle to the development of vaccines. Vaccine is introduced into human body through harmless treatment of virus, so that the body can identify the real virus without getting sick. If enough people are vaccinated or produce natural antibodies, it will be difficult for the virus to spread among people.

But natural antibodies or vaccines don't mean you can be completely protected. The immune system has a deep record of some viruses, which can be kept for a lifetime, but some viruses, such as cold viruses, are easily forgotten, and their antibodies will disappear, so that you will soon get sick again. Now we are facing such a situation in COVID-19. The virus mutates quickly in the process of transmission and has a high escape rate. Antibodies formed under the same disease virus strain can not effectively form immunity after encountering other different types of disease viruses, so a certain proportion of secondary or multiple infections will occur. In this way, the phenomenon caused by everyone's immune ability is not exactly the same.

Under normal circumstances, secondary infection is likely to occur after planting COVID-19 for half a year. In fact, according to the experience of foreign medical circles in the past, patients will be infected once a year and a half on average, so after COVID-19, everyone may be infected many times and the virus will mutate repeatedly, which is a foreseeable state in the future. But on the whole, you are unlikely to get COVID-19 again within six months after you get COVID-19.

But some people will say, my friends around me have COVID-19 and COVID-19. Why are they diagnosed again soon? Experts are still debating this issue, and I give two reasons here:

First, one of the COVID-19 is false, that is, the problem of false positive in medicine.

Rapid screening may be positive, and PCR may be false positive. In particular, the amount of this virus in PCR is very low, so the C value is very high. Maybe this time you are either infected with COVID-19 or have a false positive. Under normal circumstances, the real infection is the one with low C value and high virus amount after testing.

Second, the second strain is different from the first strain, and the virus content is higher.

Now, it has been found that although all strains are COVID-19, sometimes antibodies produced by different strains cannot fully immunize each other. For example, after you have a penis, you feel invincible now, then you take off your mask and go to KTV to sing, eat or get in close contact with many people, and then you just catch up with a different branch of the virus, which is more toxic, resulting in your second move. But usually the symptoms of the second time will be lighter than the first time.

Therefore, I would like to remind everyone here that even if you have had yang and have recovered now, don't take off your mask. Because we need to know that when you have antibodies in your body, the virus just can't enter your body to do evil, but may stay in your respiratory tract, waiting for an opportunity, always trying to get in, but it is blocked by your resistance. At this time, the saliva you spit out may still have a virus, or it may be transmitted to people around you.

In this extraordinary period, I hope everyone can pay attention to the feelings of others and wear masks in public places to reassure people around them, because there are still people around them who are not infected or even vaccinated. This is not only for the sake of others, but also your responsibility to your relatives and society.