And recently, became available the second type of testing for antibodies to the coronavirus SARS-CoV-2 by ELISA. Use it to check whether the person immune to the “crown”. In Moscow, by the way, this testing free city program was launched in mid-may, and in the whole country to test people for the presence of immunity, said the head of Rospotrebnadzor Anna Popova, will begin in June. The correspondent of “RG – Week” has decided to be tested to understand: who and why such analyses.
To the lab, we with the press photographer “RG” Marina Volosevich arrived exactly at the appointed time. The task was: give blood, and Marina still rents out the whole procedure on camera. In the laboratory, no crowds: quiet, empty, greeted us with a pretty nurse Alexandra. Security measures, of course, observe: the mask on the nose, gloves on hands, Shoe covers for sneakers. Gloves, by the way, we proposed to replace in the fresh. And rightly so – you never know what dirt we have enough, is reached.
the Procedure is used, the most common. Long documents filled out. Who among us has not handed over a blood from a vein? A thin needle, a small vial, Alexandra hand is easy – once or twice, not had time to prick, such as a vial already filled with blood. All. Free. The result after 3-4 days.
Marina and I had to “give up” with a very specific purpose (in addition to the report in the newspaper, of course). My colleague a month ago, suffered a mild cold, already sitting in isolation, and now wants to know: don’t coronavirus whether its called for, and if antibodies are really there, and in the right quantity, she’s going to go to donors – donate plasma for patients. Well, I decided to participate in the study of the immune system, which makes the Genetico center, along with several scientific organizations. Our contribution, however, modest: donated blood and waiting for an answer. But later, month through two-three, if scientists need to come here and give blood again. If antibodies to the “crown” we will be, repeated tests are needed for researchers to understand how quickly they are vanishing from the body. Depends on how long the immune response is generated to the malicious virus.
“the First study in our laboratory was conducted in April and aims to identify among doctors individuals with antibodies to coronavirus, – explained the Director of Genetico Artur Isaev. – It is assumed that people with antibodies, immune and reduced risk of developing COVID-19. We invited to participate in the research and journalists by profession, even during the restrictions and isolation continue to contact with a large number of people, that is also located in a high risk zone. And now we are expanding the objectives of the study – you want to determine the proportion of immune segment, that is, the percentage of people in the population who recover from caranaviRus. These data are important for understanding at what stage of the epidemic we are. Epidemiologists believe that when the immune stratum reaches 60-70 percent – the epidemic will end. In addition, the identification of persons with IgG antibodies and subsequent monitoring will allow to make more reliable conclusions about how stable immunity is formed in recover”.
the Study, which involved journalists “RG”, not the only one. The study of how it formed and how long the immunity to COVID-19, today scientists nits of epidemiology and Microbiology named Gamalei, SMRC of Hematology, Center for molecular and genetic research DNKOM (“RG” told about the study on may 3 in the publication “Scientists try to find out whether it is possible to recover COVID-19 re -“).
in Moscow, has begun the unprecedented project – free screening test for antibodies. Yet to pass the test by inviting people on a random sample – and it comes with a TEXT message, said the head of the Moscow Department of health Alexei Khripun, adding that may 27 is free fast everyone.
as with other regions, there is the opportunity to be tested in a commercial laboratory. These data also will be useful to epidemiologists – as explained by Anna Popova, the mass testing to determine the population immunity in regions of the country will start in June, somewhere earlier, somewhere later, depending on the situation. But now, as reported last weekend in the network mediabridge “Invitro”, such tests across the country passed more than 40 thousand people.
Interest in testing large, said the Director of strategic development and innovation “Invitro” Dmitry Fadin. Sounded interesting results: it turns out, of those 40 thousand people who came to the lab and gave a sample, about 14 percent have antibodies to the “crown”. This is the national average, the situation from region to region, of course, is different, said Dmitry Fadin.
In Moscow, according to Khripun, immune defense now has 12.5 percent of the number of people who have undergone tests, such already 50 thousand.
And now – a few simple questions and answers about testing.
1. If the test confirms that I have the antibodies, it means that I am protected and can not wear a mask, not to comply with the restrictive measures?
No, unfortunately, 100 percent guarantee the protection of a positive test result does not. It is important not only the presence of antibodies, but their combination and quantity. There are two types of antibodies: “early”, which appear in the first days after infection, antibodies of IgM and more “late”, they are determined from the second-third week – IgG. The high level of “late” antibody indicates the best degree of protection. If the analysis shows the presence of IgM, even at a time.Ameno with IgG – this could mean that the person has not had chickenpox and can remain potentially dangerous to others. Not accidentally, Alexei Khripun said that people with identified IgM will be offered to pass a test PCR to check whether there is still virus in the body.
the test Results do not mean that a person may cease to comply with the restrictive measures “is not an indulgence,” said Alexei Khripun.
2. As it is, the test is positive, but not immune? Why is this possible?
the fact that the study of the properties of SARS-CoV-2 continues for too long, and while scientists can not definitely answer many questions about antibodies is: what is their level protects from infection, how long they will be stored in the body. There is only speculation: some scientists say that immune to similar to the current coronavirus the SARS virus (it was the cause of the SARS outbreak in 2002-2003) is about two years, so that the resistance of the “crown” may be the same. Others have likened the current coronavirus from other respiratory infections and believe that it will be “seasonal” and to instill in him will have every year.
3. But if the tests do not give a clear answer, why do they do that?
the Causes can be different. Someone had a cold and wants to know – “crown” it was or not. Someone is trying to donate plasma or just a volunteer. Still the risk of being a carrier of the virus with antibodies is much lower than those who don’t.
let’s Not forget about the professions that are constantly in the midst of people: doctors, employees of city services, builders, students and simply office workers who put in “open space”. Knowledge about one of the workers formed the immune system, will help to properly allocate risks at work. In larger scale tests allow us to estimate the proportion of survivors in the population, and calculate the proportion of those who recovered from the infection without symptoms. In the end, this will allow epidemiologists to correctly assess the situation, predict its development and to take the necessary preventive measures.
Finally, the study of immunity is necessary for the development of effective vaccines against coronavirus.
So at this stage of knowledge about СOVID-19 the main argument in favor of testing – a contribution to the study of a new infection. Small and inconspicuous, but the contribution.
Perhaps the immune system of those who are not infected with the novel coronavirus or have been ill in the form of light, was ready to attack the new pathogen. The immune system could “toughen up” in the fight against other coronaviruses that cause symptoms of the common cold. To such conclusion scientists of the Institute of immunology at La JOLLA, California.
For the formation of the immune system are responsible not only antibodies – immunoglobulins that org��the body produces in response to the contact of the virus. There are special cells “immune memory” T cells that can recognize trapped in the body of the pathogens that the body has encountered before in the course of life, and to destroy them, not allowing to develop the disease. Scientists have found such cells that can fight with the new coronavirus in blood samples taken several years ago. People who took blood, couldn’t hurt a new “crown”, but were infected with other coronaviruses, which cause only cold symptoms.
“This discovery gives us hope that some of them may already be some degree of protection and this may explain the seeming randomness of how serious are coronavirus defeat. However, whether that person had a cold, can be a protective factor outside the laboratory remains to be proven,” wrote The Times, talking about this research with reference to the journal Cell.
“In the study, considered the so-called T-cells. They differ from antibodies: this is not protein particles attached to the virus and acting on it. T-cells detect cells that are already infected with a virus. There are two types of T-cells. The so-called T-helper cells identify infected cells and T-killer cells attack and destroy them. As in the case of antibodies, T-cells produced in response to infection, and then permanently stored in the body,” – says the publication.
to Find in older blood samples of T-cells which reacted to a new virus, the scientists came to the conclusion that the immunity generated during infection by other coronaviruses, may persist long enough to protect also from the new coronavirus. This is what scientists explain that children usually suffer the “crown” easily (coronavirus colds are a common thing for them). Perhaps the same mechanism is triggered in adults who have retained immunity after previous colds.
However, it is, of course, a preliminary result that needs verification and confirmation. “Seasonal coronaviruses circulate constantly, causing Ari and diarrhea in 10-20% of the population each year, – told “RG” Deputy Director of Institute of epidemiology, corresponding member of RAS Alexander Gorelov. – That is a long lasting immunity after suffering a coronavirus infection (as, indeed, in the case of the flu) in humans does not occur. Not by chance, we should do an annual flu vaccine. So there is no reason to believe that had been ill informed by another coronavirus, we are protected from the new”.
IgG Level:
<0,95 – antibody not detected:
0,95-1,4 – indeterminate result requires a reanalysis of 10 days;
>1,4 – antibodies detected.
IgM Level:
<0,95 – antibodies were not detected;
0,95-1,1 – ��anicely a result, required re-analysis after 10 days:
>1,1 – antibodies detected.
