According to the expert, testing is of no benefit – but the threat to the wallet is significant
In St. Petersburg, a huge number of private clinics invites everyone to take tests for antibodies to coronavirus. This procedure, to put it mildly, is not too cheap – its cost starts from 700 rubles – and, most importantly, is not entirely clear. What do antibodies show? How quickly do they disappear? Is it possible to get infected again, if they are? “Komsomolskaya Pravda” -St. Petersburg collected all the most pressing and popular questions and addressed them to an expert – a doctor of medical sciences, a specialist in especially dangerous infections Vladislav Zhemchugov.
Question 1. What antibodies exist?
– Antibodies to coronavirus are divided into two types – lgM and IgG, – explains the scientist. – IgM appear on average one week after exposure to the virus. IgG begins to form on average on the 21st day. IgM is stronger – they literally “strangle” the virus, prevent it from developing and “poisoning” the body. IgG is correspondingly weaker. They also fight the virus, but to a lesser extent.
Question 2. How long do antibodies last?
“By themselves, IgG antibodies disappear after three to four months – as soon as the body defeats the infection, it stops their synthesis,” Zhemchugov continues. – The body is smart, it does not need to keep everything in the blood. But! The so-called memory cells are preserved, in which it is clearly “written” – what kind of antibodies are, how to produce them, under what conditions and in what quantity. And in case of repeated contact with the virus, the body, guided by these “records”, again begins to synthesize IgG antibodies. And it takes him not 21 days, but only three.
Question 3. So is it still possible to get infected again if the body already has antibodies?
– Unfortunately, science is not yet aware of this, – the specialist states. – On the one hand, at the moment, only two cases of re-infection with the SARS-CoV-2 coronavirus have been described in the world, and both of these descriptions, frankly, do not inspire confidence. It is not clear that this is in fact – indeed, a person who had previously been ill, contracted again, or simply the amount of the virus in his body first decreased to an undetectable scale, and then, when the treatment was stopped, it began to increase again.
On the other hand, I repeat, a reliable and reliable answer to the question “does a person develop a stable response to coronavirus?” we haven’t received it yet. It has only been proven that IgG antibodies are able to “soften” the course of the disease, to prevent the development of severe complications.
But here, by the way, we can recall the sensational story of the Diamond Princess cruise ship, where right in the middle of the cruise there was a massive outbreak of covid among passengers. As it became clear later, there were people among them who had been ill even before they set sail. And they somehow escaped re-infection – despite being in a confined space with dozens of carriers. We do not know exactly what helped them, but we would like to believe that the acquired immunity.
Question 4. Can antibody tests be trusted?
“Today, there are dozens of test systems in the world,” notes Zhemchugov. – And because of this, confusion regularly arises. All systems are very different, and among them there are many that are not calibrated for specificity. Let me explain: there are 43 varieties of coronaviruses as such. And they are all similar to each other – it is not for nothing that virologists have combined them into one family. This is, for example, a family of conifers. Every tree has a trunk, roots and branches. But a layman is unlikely to distinguish between spruce and fir by eye. So it is with viruses.
Therefore, an antibody test may well give an erroneous result and react not to our notorious SARS-CoV-2, but to one of its closest “relatives”. So if you still decide to do the test, you must first find out from the doctor everything about him in more detail, and ideally, ask for instructions and find the line there “specificity”… If the specificity index is more than 99.9%, such a test can be trusted.
Question 5. So is it still necessary to do an antibody test?
– My opinion is this is a waste of money, – Zhemchugov concludes. – The maximum you will know is whether you were sick with coronavirus or not, and if you were sick, then how long ago. And of course, if the test turns out to be positive, this does not mean that you can now neglect security measures. Until scientists have reliable data on how strong and long-lasting immunity is formed, you are still at risk.
On the other hand, if you have antibodies in your blood, this means that you should inject the coronavirus vaccine no earlier than a year later. Otherwise, “imposed” from the outside, artificial immunity to the virus will simply destroy your own. This is something worth thinking about.
ON A NOTE
Antibody tests at the expense of the budget in St. Petersburg are done only to doctors – once every three weeks, all healthcare workers are tested on a mandatory basis. All the rest – only at their own expense in private clinics.
An antibody test in clinics in St. Petersburg costs from 700 to 2,500 rubles. This is if separately. If together – and IgM and IgG – from 2,000 to 4,500 rubles. If, on top of everything else, you want someone to come to your house, cook another 1,000.
Author: Sergey Volchkov