Doctors around the world are working on a vaccine against the new coronavirus infection. We asked a few naive questions to a specialist in order to understand how this system works.
doctor-therapist of the clinic “Semeynaya”
According to information at the beginning of July, more than 100 vaccine candidates are being studied, each of which, over time, could save millions of lives. But another thing must be admitted: it is possible that none of them will be approved for use… And there are many reasons for this.
First, it is short timein which humanity wants to get a vaccine. Typically, the vaccine development process takes 10-15 years and is extremely time-consuming, and the result is not always guaranteed. The latest record belongs to the firm that developed the Ebola vaccine in just five years. A vaccine for COVID-19 is planned to be developed in a year and a half, and if it succeeds, it will be a new record.
Secondly, doctors are interested not only in the fact that the vaccine is safe during administration: it does not cause allergies, does not infect a person with the same pathogen from which it is designed to protect, does not lead to serious side effects, but it should be safe and in long-term periods after administration (it did not provoke immune diseases, did not weaken immunity to other, related pathogens – it also happens), and this requires long-term clinical trials, during which doctors can monitor the health of vaccinated volunteers.
In the case of the COVID-19 vaccine, humanity seems to be faced with a choice: either here and now, but with unknown consequences, or repeated waves of pandemics with their victims, but intelligible clinical trials.
Today, there is even no certainty that vaccine prototypes can work in principle. And the “sane” vaccine can be expected no earlier than in 10 years: no one has canceled the laws of science.
What is a vaccine prototype?
– This is an experimental model of a system for delivering the COVID-19 virus substance into the human body, in which the virus substance is designed to train the patient’s immune system to recognize and destroy the virus without causing a coronavirus infection. At the same time, it is desirable that the “knowledge” gained from training with the vaccine remain in the memory of immunity for as long as possible, at least not less than a year, even better – for several years, very well – for 10 years, ideally – for a lifetime.
Several countries are currently developing. How do they differ from each other? Which ones are more effective?
“Different countries are now testing different prototype vaccines, as investors and vaccine manufacturers have adopted some model of training the immune system that they have found to be beneficial. It’s actually a lottery. Let’s see what prototypes of COVID-19 vaccines are now.
Attenuated (attenuated) viral vaccines most effective in fighting viruses, but can infect humans. The main task of the virus is to reproduce, and not at all to kill the host. When a weakened mutant is injected into a person, the immune system reacts to it like a normal virus, but the virus is no longer able to cause disease. What is the problem here? There is a chance to inoculate a patient with a real virus, and at one time this happened regularly, for example, with vaccinations against polio. The United States and India are developing this prototype.
Killed viral vaccines, unlike the weakened, but alive, are deprived of their main drawback – they are not able to cause infection from vaccination. This is because the virus in the vaccine has previously been destroyed. The cells of the immune system somehow understand that anxiety is more educational, and do not give a persistent and strong response. Scientists have learned to deceive them with the help of adjuvants – substances that whip up “fear” and increase the sense of “civic duty” in immune cells so that they learn to defend themselves better and give a good response. The most promising direction in adjuvant modulation is the creation of virosomes. These are a kind of ghostly images of a pathogen, which the cells of the immune system perceive as real and attack it as if it were real. To do this, the proteins of the virus are glued onto a small ball of fat, and the result is very similar and convincing. These prototypes are mainly handled by Chinese companies.
Protein vaccines – here the idea is the same as in the case of the pathogen ghosts from the previous example. We just do not take any fat globules, but inject a large amount of virus envelope proteins into the patient’s body, and the immune system learns from the fragments in the same way. What’s the catch? The biosynthesis of such proteins is very, very expensive in terms of time and money, the resulting product must be thoroughly purified. No country dared to master this prototype.
Vector vaccines – the most fashionable trend and, obviously, the most realistic prototype of all. The idea is this: a harmless virus (transport vector) is taken, which genetic engineers cut off the program so that it either can or cannot multiply in the human body. Scientists have inserted a coronavirus gene into the virus, which is not capable of producing a whole virus, but is responsible for the production of some significant viral protein. The patient’s cells, infected with the genome, begin to churn out a viral protein, and the immune system responds to it. If the vector virus can multiply in the human body, then a long-term immune response is formed (in theory), if not, the response is not strong, the vaccine will have to be administered again. The United States and Great Britain are developing such vaccines.
How does the vaccine work?
– A vaccine is a training set of molecules that make up a causative agent. On it, the immune system learns to recognize the pathogen. The fact is that the recognition of the causative agent of an infectious disease in the immune system takes on average 7-14 days (some pathogens can be masked for years or months), and during this time the pathogen can cause significant harm to a person. If you teach the immune system in advance to recognize the enemy by sight, when it enters the body, the pathogen will be destroyed immediately.
How are vaccines tested?
– There are several phases of testing any medicinal product, each of which answers its own questions.
Test first phase start on laboratory animals. The most important safety aspects are being investigated: whether the vaccine is compatible with life, what side reactions it causes, whether it affects the offspring, the ability to reproduce, etc.
Test second phase are possible only if no serious violations were identified in the first phase. The second phase examines the effects of the vaccine on perfectly healthy volunteer candidates. Therefore, in Russia, servicemen were selected for this purpose – logically, the healthiest can be found there.
If no serious irregularities are noted during the tests of the second phase, the tests begin. third phase – on ordinary people who may have a variety of risk factors: age, concomitant diseases, overweight, diabetes, daily medication, etc. And only if the third phase ends positively, the vaccine will be given the green light.
Why do I need to be vaccinated periodically?
– The fact is that, on the one hand (as discussed above), different types of vaccines have a different ability to “irritate” the immune system. Live attenuated vaccines do this best, but they carry the risk of contracting the disease itself. On the other hand, some viruses (and, alas, a new coronavirus from this number) are able to mutate, changing their outer “outfit”, while our immune system has to recognize it anew each time. But let it not scare anyone: influenza vaccination follows this path. Each year, scientists predict which of the influenza viruses will “tour” and put in the vaccine those proteins that are most likely to be in the suit of the virus.
What tests can I get for COVID?
– If you have an acute illness: fever, sore throat, runny nose, cough, it is best to have a smear. If you are sick for more than 10 days and a new coronavirus infection is suspected, do an analysis for class M and G antibodies. If you have been ill for a long time and are now healthy, but want to know if it was a coronavirus, get tested for class G antibodies.