Testing for antibodies to the coronavirus in Russia was carried out on a large scale: in Moscow alone, several million tests were conducted during the first year of the pandemic. However, foreign experts unanimously assure (and their scientific studies prove) that such tests have no special significance. Their results are extremely unreliable and do not allow for confident conclusions about anything – especially the level of human immune protection. Actually, it’s a waste of money, but that’s not the point. The danger lies in the fact that taking such a test can give a person the illusion of protection – as a result, many allow themselves to not strictly follow restrictive measures and generally engage in riskier activities.
Russia is one of the few countries where medical institutions actively offer everyone the opportunity to be tested for coronavirus antibodies. Budgets at all levels, from federal to corporate, spend millions of rubles to cover the cost of these (conditionally free) tests, although there are also many people who are willing to pay for them themselves. The capital’s health department website promises that the test results will show “if you were asymptomatic and have developed immunity.” “The blood test from a vein determines with high accuracy whether there are antibodies to the virus in the blood,” Moscow residents say. “They indicate whether a person is currently infected or has already recovered from the infection.”
An attractive offer is met with demand. Moscow Deputy Mayor Anastasia Rakova said that during the first year of the pandemic, nearly 7 million tests for covid-19 antibodies were performed in the capital alone. This is only a third less than the number of PCR tests, which determine the presence of the virus itself. For comparison, in the entire United Kingdom, which has more than five times the population of Moscow, one and a half times fewer antibody tests were performed in the first 18 months of the pandemic than in the Russian capital (4.3 million). In the United States, such statistics are not collected centrally, not even at the level of individual states.
The thing is, the accuracy of such tests leaves much to be desired, and scientific research consistently and quite convincingly demonstrates that the concentration of antibodies to the coronavirus in the blood of those who have had the virus and those who have been vaccinated is only indirectly related to the level of protection against Covid-19.
We explain quickly, simply, and clearly what happened, why it matters, and what will happen next. The number of offers should remain: episodes. End of story: Podcast Advertising. “The presence of antibodies is only half the picture,” says molecular biologist Konstantin Andreev, a researcher at the Howard Hughes Medical Institute and Northwestern University in the United States. “There is also a cellular immune response that lasts longer and is not detected by antibody tests.” In other words, you can have a low level of antibodies but still have good protection against the virus because of cellular immunity,” he explains. It can also be the opposite: for example, the first dose of the vaccine can induce a sharp increase in antibody levels, but this immunity will be fragile and will only be strengthened when other defense mechanisms come into play. “The antibody test, which is very popular in Russia, is almost never done here in the U.S.,” Andreev notes. “Insurance does not cover it, unlike testing for the virus itself or vaccinations.” No insurance company, he says, “is going to pay for something that makes no sense. And an antibody test is much more meaningful to scientists doing historical research than it is to a specific individual. That’s right, for example, in the spring of last year, the Italian town of Vò Euganeo determined the proportion of asymptomatic cases of Covid-19 by testing all its inhabitants for the presence of specific antibodies and understanding who had already been exposed to the virus and who had not. Antibody analysis played an important role in the story of the Diamond Princess, as scientists discovered that many people on board the ship had been infected with Covid-19 without showing any symptoms and without even knowing they were sick. However, from the perspective of a particular consumer, the value of the results of such an analysis is highly questionable. An antibody test is not suitable for diagnosis, treatment or prevention of Covid-19 infection. Medical advice to periodically check antibody levels and, if they begin to decline, to be vaccinated again, the scientist urges not to listen. “This is complete nonsense. It is clear that someone wants us all to be tested and vaccinated every six months or even every month. But there is no such data. [Antibody testing is just a business,” the expert asserts.
In Russia, the widespread availability of antibody tests has caused the third phase of clinical trials of the “Sputnik” vaccine to be virtually disrupted. Many study participants voluntarily took the test, which revealed the control group: the volunteers who received a placebo injection had no antibodies. Many of these volunteers decided to get vaccinated again – with the real “Sputnik”, which completely confused the map developers. The research was disrupted and the recruitment of volunteers had to be stopped.
That’s why in many countries around the world, individual antibody testing is not only not encouraged, but the authorities actively convince people of its uselessness and discourage them from spending money on it. In particular, the CDC website clearly states that these tests are not suitable for diagnosing the infection, as it takes up to 3 weeks for the body to produce antibodies after infection. So a negative test does not necessarily mean that a person is healthy, and a positive test does not guarantee that they are sick. Antibody tests are also not suitable for determining the level of immune protection, U.S. officials warn. However, if for some reason you decide to take such a test, the CDC strongly advises against making any decisions based on the results. A separate line cautions against drawing conclusions about the need for vaccination or revaccination after recovery from an illness. As an additional argument against individual testing, a number of other disadvantages of this method are cited. For example, some tests may only detect antibodies that remain after a previous infection, but not after vaccination, which only adds to the confusion and increases the risk of misinterpretation. There is also a possibility that the test may falsely show a positive result due to a phenomenon called cross-reactivity, in which antibodies left over from a cold are mistaken for immunity to Covid-19. Taking all these factors into account, it is obvious that the question of determining the level of immune protection by means of such a test is not even worth considering. It is quite easy to measure the concentration of antibodies in the blood using special equipment. It is much more difficult to draw meaningful conclusions from the numbers obtained. The fact that the virus continues to mutate (and will continue to mutate) only adds to the uncertainty. Scientists cannot yet confirm that the antibodies produced by the body in response to a previous infection or vaccination against Covid-19 will remain as effective against the constantly emerging variants of the virus – and how long this will last.
Sooner or later, the virus will most likely evolve and learn to evade our immune defenses. Some studies suggest that this process has already begun. Just a few days ago, the journal Science published an article in which the authors discovered that the plasma of recovered COVID-19 patients copes significantly worse with new variants of the virus. The number of offers should remain the same. This makes predicting the level of immune protection based on antibody levels alone even more difficult – and individual testing increasingly akin to fortune telling on coffee grounds. “If specific antibodies to the coronavirus are found in blood serum, this indicates that a person either has had the disease or has been vaccinated. However, this tells us very little about the protective nature of the immune response,” the article’s authors write. “Neutralizing antibodies capable of recognizing the spike protein provide more information in this regard. However, their traditional measurement requires the construction of cell-virus systems, which are expensive, time-consuming, inflexible, and pose a risk of infection to the personnel performing the test.” According to Professor Vasily Vlasov, an epidemiologist at the Higher School of Economics, specialized laboratories with the highest level of biochemical protection are needed to conduct comprehensive research capable of measuring different components of the immune response and providing more accurate predictions. Calculating the concentration of antibodies in blood plasma is certainly much easier and cheaper, experts agree – but why? After all, there are three types of antibodies, and ideally only one of them needs to be counted. “The potential for immune protection can only be determined by the level of neutralizing antibodies,” explains Professor Didier Trono, senior author of the Science article and Professor at the School of Biological Sciences in Lausanne. “And a standard serologic test is not even able to distinguish whether they are neutralizing or not. It measures all the antibodies together, without distinction.”
When asked if any conclusions can be drawn from such an analysis, Professor Trono waves his hands and says: “The result of such a test only indicates the fact of a past illness or vaccination. “However, if the antibody titers are very high … then it is likely that the neutralizing activity there will be at a good level,” he suggests. But so far, this is just a theory. Scientists still do not know what level of antibodies is needed to provide effective protection against the virus. And they are not sure that this question can even be answered. According to Professor Vish Viswanath of the Harvard School of Public Health, we still know so little about the new virus, and the recommendations are changing so rapidly, that many people around the world are simply tired of the uncertainty. Yes, an antibody test cannot determine the level of immune protection. But it can give someone confidence and the illusion of control, which is not bad in a time of global crisis. “People try to cope with a huge flow of information in one way or another, including taking steps of varying meaningfulness just to feel like they are doing something to avoid infection,” explains Professor Viswanath. “In such moments, official advice is simply ignored.” “At the moment, the only thing that makes sense from a scientific point of view is to get vaccinated against the virus as soon as possible,” he concludes.