A specialist answered the readers’ troubling questions about the coronavirus.
Doctor of the highest category, chief physician of the Nearmedic network of clinics
Before vaccination, I took an antibody test. I did not understand anything in decoding, it turns out that there are IgM and IgG antibodies. How do they differ? (Inna, Moscow)
– The immune system reacts to an antigen – any foreign molecule, in this case, a coronavirus molecule that enters the body. It carries in itself foreign genetic material. The immune system reacts to this molecule, producing antibodies. That is, there is a confrontation between antigen and antibody in the body. It is important to understand that a molecule is a protein structure, but there are several proteins (N-proteins, S-proteins, M-proteins). Against each of them, specific antibodies are produced (otherwise, immunoglobulins).
Today, both doctors and patients are aware of the existence of M-immunoglobulin, immunoglobulin I and G. Each performs its own function by interacting with certain parts of the coronavirus. And they are produced at different periods of the disease. The first to appear are immunoglobulins (antibodies) M. They are low-power, but they work against several proteins, trying to protect the body from all foreign molecules. Immunoglobulins G are more targeted, they act against proteins S and N. The coronavirus molecule has spikes on its surface – this is an S-protein, a glycoprotein, it first clings to a cell in the human body. It is immunoglobulin G antibodies that protect us. The faster they are produced, the less clinical manifestations of the disease.
She suffered a severe coronavirus, passed a PCR test before discharge, it turned out to be negative, but an antibody test revealed the presence of IgM. They say they are in the body only during illness. Is it so? (Anna, Moscow)
– There is nothing surprising in the results of the study, immunoglobulins (antibodies) M appear on the 4th-6th day of illness and, as has already been proven, can persist in the body for a long time, up to two months.
Now there is a lot of talk about the need for vaccination, but should those who have already suffered from COVID-19 need to be vaccinated? (Andrei)
– It is necessary to assess whether you have antibodies G. Their presence indicates that the body has its own defense against the virus. But it is important to remember: antibodies are not permanent, according to studies, they last for 3-4 months. Moreover, this indicator is individual. Upon completion of treatment (after 3-4 weeks), the first assessment of the level of antibodies in the body is carried out, then it is recommended to repeat the study every 3-4 months in order to track the changes and decide with the doctor about the need for vaccination.
I have not been sick with coronavirus. Do I need to take an antibody test before vaccination? (Sergei)
– Yes, at least in order to understand whether it is necessary to get vaccinated right now. The level of G antibodies can change, and not only in a lower, but also in a higher direction. This happens if a person is suddenly faced with an infection again. This can happen without any external signs. With each provocation of infection, antibodies continue to be produced. Therefore, it is difficult to determine the duration of their existence in the body.
Before vaccination, it is still worth taking a PCR test. His positive result is a signal to stop vaccination, because this means that you are sick at the time of the study. It has long been known that a patient does not always have external signs of coronavirus.
I’m going on vacation in the summer. How to calculate the time of vaccination, is it possible to get vaccinated 10 days before the trip? (Angelina)
– No, 10 days is not enough time, antibodies are produced within 21 days. Therefore, do not hope that after being vaccinated, you immediately find yourself under a protective cap and can run into the red zone. No! For three weeks, you avoid unnecessary contact, then do an antibody test to understand the degree of protection. Because the response to vaccination is individual for each person.
Sources:
1. Maria Ordzhonikidze, doctor of the highest category, chief physician of a network of clinics .