Capital virologists were encouraged by the Russians: national vaccine against the coronavirus was successfully tested on volunteers. It will be the world’s first vaccine against “the plague of 2020” — the authors characterize her as a recombinant adenovirus vaccine, and claims that it does not contain the components of the actual coronavirus. It just is similar to the desired immune response. Testing — not the last stage in the development of a vaccine before its release, so the exact answer to the question “when?” did not yet exist. What exams must take the vaccine to be admitted to the consumer, “MK” told the doctor of medical Sciences, virologist Hope Uminova involved in the development of a number of domestic vaccines.
In the first place, the expert said, we should remember that viral infections there are two types of immunity: humoral, which is expressed in the antibodies that can be detected in human blood and cell, reacting directly on the penetration of the virus. This second type of immunity neutralises the virus at an early stage, he has not yet managed to infiltrate the cell, and therefore particularly effective. Unfortunately, cellular immunity to study difficult and quite expensive, although once such studies have been conducted in Russia, only against other pathogens. Today’s virologists focus most often on humoral parameters.
A good vaccine in preparation for clinical use is the standard three phase test in vitro, i.e. in laboratory cultures, in vivo, that is, on animals and on volunteers, says Hope Uminova. — Preclinical studies it is essential to perform at the highest level, since each phase for unpleasant surprises. So, when in the 2000s created a vaccine against MERS — middle East respiratory syndrome, caused by another form of coronavirus, laboratory ferrets, which tested the drug, got a good antibody indicating that the virus is neutralized. But it was necessary to expose animals to repeated exposure to the causative agent, as their condition has deteriorated significantly: the immune response provoked by the virus in vaccinated individuals was too active.
According to the virologist, there are several parameters that must match the vaccine. The first of them — security in the production process and during the use of drugs. A new vaccine must not cause excessive immune reactions. Neither the children nor the elderly, nor people of middle age. The second mandatory criterion is protectionist, it is possible to induce specific immune defenses of the body when certain infectious disease. The presence of antibodies does not always mean that the vaccine protective antibodies to some antigens are not protective action and, therefore, at the second meeting with the virus will not be able to neutralize him.
Next, a very important duration of immunity generated — emphasizes Uminova. — It must be said that vaccines against coronavirus have long existed for animals and the duration of the generated their immunity is guaranteed exactly one year. This is the minimum, in my opinion, the term duration of immunity for mass vaccine: if vaccine need to be repeated more frequently, this is unacceptable, because each immunization is although low but still a risk for the body.
The following important parameters of the vaccine relate to the convenience of production, procurement and use, he said. They are obvious: the vaccine should not be too expensive, it should be as biologically stable during transport. Standard option — vaccines are quite stable at low temperature. In drugs, as a rule, the stabilizers are introduced which allow the virus in the vaccine composition to inaktivirovanie. The introduction of the vaccine or preferably intramuscularly or subcutaneously, or orally: intravenous or intra-arterial injection important sterility, which is difficult to achieve in production of the vaccine.
Finally, it stresses the Hope Uminova, it is essential that the vaccine was of low reactogenicity. A reaction to the vaccine should not repeat the clinical picture of the infection. Local redness at point of injection, for example, valid, and high fever — no. Most of all is to be feared too active immune response in the Philippines, a vaccine for the Ebola virus a few years ago caused a high infant mortality for that reason. This must be absolutely excluded.
— In the world today announced the creation of more than 140 prototypes of vaccines against COVID-19, but none has reached the stage of formal confirmation, says the virologist. — Some of the vaccines, as far as I know, entirely new mechanisms of its action. I’m sure that, before approving the use of any vaccine and the coronavirus is no exception, need special attention, the utmost caution. Russia needs a national vaccine: we understand that only this ensures we receive quality of the drug in appropriate quantities. But I will note that haste should not be here: given the relatively strong public skepticism, it is crucial that the creators of the vaccine could be trusted fully. And for that all stages of testing need to pass in full, all requirements for the vaccine to perform. Meanwhile, given that the agent COVID-19 active and the epidemic until the end has not subsided, we need to wait and observe safety precautions.