Text | Little Pharmacist of Shanghai Beach
As we all know, the human body will produce specific antibodies after being vaccinated with the new crown vaccine, so that the vaccinated people will have a certain degree of immunity to the new crown virus re-infection.
So if after vaccination with the new crown vaccine, it is determined that the body already has new crown-specific antibodies, will it not be infected by the new crown virus? Before, after being vaccinated, it was also found that some people were still infected by the virus.
Is it because they did not produce antibodies in their bodies, or because of other reasons? Regarding whether you will be infected after vaccination, and the resulting series of questions, this article will discuss and analyze.
Not all viruses will produce corresponding antibodies after infectionNot all viruses will produce corresponding antibodies after infection
Antibody is a special protein in the blood.
It is part of the body's immune response to infection and a signal that humans may be developing immunity.
Specific antibodies correspond to specific virus types.
However, after antibodies are produced, there is no guarantee that individuals will be protected by antibodies for life, because antibodies will also disappear.
Some types of antibodies may not exist in the human body for more than a year.
Most people infected with the virus will produce the corresponding antibodies.
In fact, the body is infected with any virus, and ultimately self-healing depends on antibodies.
For example, if someone has been exposed to the measles virus, those who have been infected with the virus will be immune for life.
On the contrary, for influenza viruses or common cold viruses, even if they are vaccinated and prevented every year, their diseases or symptoms may still recur again and again, year after year.
The reason behind this may be that the symptoms of most cold viruses are relatively mild and have little impact on the overall function of the human body, so the immune system will not produce a complete response, which may not really stimulate the body’s immune response and produce effective And sufficient antibodies.
Antibody is not a question of presence or absence, there is also a question of titerAntibody is not a question of presence or absence, there is also a question of titer
In general, the ability of a certain virus to induce the body to produce antibodies (the degree to which it stimulates human immunity) is closely related to the severity of the acute disease induced by the virus.
People with severe illness have much longer immunization times, sometimes even as long as several years.
However, the characteristic of the new coronavirus is that most of the symptoms are relatively mild, which can be regarded as a self-limiting disease; however, a relatively small group of people have mild early symptoms, but will gradually become severe, and the symptoms will become very serious.
Because, during the infection process of the new coronavirus, its immune response occurs relatively slowly, which may not enable the population to obtain immunity quickly and in a short period of time.
Although most people who have recovered from the new coronavirus infection have already produced antibodies in their bodies, the rate of antibody production is relatively slow, and the spread of the virus may have become more widespread during this period.
Therefore, vaccinations (harmless virus analogs) in advance can make the body immune to the virus in advance and prevent the spread in advance.
At the same time, after the antibody is produced, it still faces the problem of titer.
Titer is actually the concentration of antibodies in human blood.
This neutralizing antibody is like the armor of the human body.
The higher the titer of the antibody, the stronger the body's defense against viruses and the denser the armor.
However, armor is not a panacea.
Viruses and antibodies are the relationship between spears and shields.
Although the shield is strong, the spear is constantly evolving.
For example, when a virus evolves into a new type of virus, the old antibody may lose its defense.
In addition, when the human body is in a place where the virus is rich for a long time, the production of antibodies in the body is lower than the speed of virus replication, and infection and symptoms will also occur.
Antibodies are not a panacea, the body’s immunity will also declineAntibodies are not a panacea, the body’s immunity will also decline
As we all know, antibodies have protective effects, but excessive antibodies may be harmful.
Certain antibodies can cause inflammation and cause the body to overreact, and this overreaction can even be fatal.
This phenomenon is relatively common in the current field of antibody treatment of tumors.
When a large number of antibodies against tumors are injected into the human body, a strong immune response may occur in the human body, leading to a more dangerous situation.
The detection of antibodies to the new coronavirus can determine whether the vaccine is really effective after vaccination, and it can indicate whether a person is immune when exposed to the virus again.
However, in fact, it is still unclear how long this antibody can exist in the human body and how long it can be immune.
In general, antibodies in the human body have a lifespan, and they are usually difficult to exist permanently, and their existence may be as short as a few months or as long as a lifetime.
The question of whether antibodies to the new coronavirus can exist and persist in the human body for a long time is still unconfirmed.
Scientists all over the world are working hard to find the answer.
Figure 1 Literature source Z.
He et al.
Lancet 397, 1075-1084; 2021).
Even if you have experienced a viral infection, you may still need to be vaccinatedEven if you have experienced a viral infection, you may still need to be vaccinated
Beijing Concord analyzed the blood samples of more than 9,500 people (see Figure 1 for the source) and found that about 40% of patients infected with the new coronavirus developed neutralizing antibodies.
Therefore, the researchers concluded that most people in Wuhan are still susceptible to SARS-CoV-2 infection and a large-scale vaccination campaign is needed to achieve herd immunity.
Such research results have also been confirmed by several case studies abroad.
For example, there have been cases of infection with the new coronavirus until cured, and repeated infections twice or more.
Therefore, whether it is a virus vaccine that has been infected with the virus or has been vaccinated before, if there is insufficient antibody protection in the body after testing, it means that the body's defense against the virus is limited, and it may still need to be vaccinated again to continuously resist the new Increased and mutated viruses.