13 Oct 2021

Chumakov Center Director Aidar Ishmukhametov: CoviVac effective against Covid-19 with no serious side effects

Aidar Ishmukhametov

Aidar Ishmukhametov
Photo: Chumakov Research Institute

The CoviVac inactivated vaccine developed by the Chumakov R&D Center of Immunobiologicals is Russia's third registered coronavirus vaccine, which became very popular as soon as it was put into circulation. Chumakov Center Director Aidar Ishmukhametov has given an interview to Interfax in which he speaks about CoviVac's Phase III of the pre-clinical trials, as well as preparations to present to the Health Ministry the results of the pre-clinical trials with respect to Delta variant of Covid-19.

Question: Please tell us about Phase III of clinical trials of the CoviVac vaccine. How many volunteers are involved and what age are they? Are there any undesirable effects?

Answer: Active enrolment of volunteers is underway for participation in Phase III. Our study is open, so all volunteers are guaranteed to receive the vaccine. The study involves 18 clinical bases across Russia, and we are planning to monitor the volunteers for a year after vaccination. For the control group, we will use data of unvaccinated people from cities where the study is being held. At present, in the framework of clinical studies we have not had any reports about serious side effects. A number of volunteers displayed brief sleepiness, soreness at the injection site, exacerbation of allergic reactions, but nothing else.

Q.: Are people over 60 involved in this phase of trials? Has the Health Ministry authorized engaging volunteers of this age group? Has the issue of triple vaccination of people over 60 and people with chronic diseases been resolved?

A.: We are now awaiting the authorization of the Health Ministry for clinical trials of volunteers over 60. We will be comparing the efficacy of injecting two and three doses of the vaccine for this age group. Since older people are at risk of a severe course of Covid-19, our task is to ensure their utmost protection, which may require three doses. Many years of experience prove that revaccination by inactivated vaccines is effective and safe; however, the information about the feasibility of using one or two doses for older people, as well as people with chronic diseases, can be added to the directions for use only after clinical trials.

Q.: How effective has the vaccine been since the beginning of mass immunization with it? To what extent does the vaccine protect against, for example, the Delta variant and severe course of the disease?

A.: We have joint projects to monitor patients with the coronavirus infection with several hospitals. There, we are not only watching changes in the circulating virus variants gathering material from those who have fallen ill but also studying very closely the medical records of those hospitalized, comparing them with data about vaccination. And we are content with the current result. However, we monitor not only changes of the circulating variants of the virus by gathering material from sick people, but also examine very closely the medical histories of hospitalized persons, comparing them with data on completed vaccination. And we are satisfied with the current result. Among people with confirmed coronavirus, we did detect a small number who were immunized with CoviVac, but their symptoms are much milder than those who did not get vaccinated.

As for the effectiveness against new coronavirus variants, the short answer is there is protection. To go into more detail, antibodies to the virus surface structures are developed in response to vaccination, and this is not just a single clone of antibodies but a set of them. When a virus changes and a new variant emerges, then surface structures may also change. But the possibility of such changes is limited, since the virus is still using the spike protein to get into the cell, and this requires it to bind with a cell receptor. That is why some antibodies developed after the immunization with vaccines based on the initial SARS-CoV-2 also bind with a cell receptor. Both foreign and our own studies show that current vaccines are to a large extent effective against new variants.

Q.: It was reported earlier that the vaccine showed 80% efficacy after Phase I and Phase II of the clinical trials. Does this mean the efficacy of the vaccine or the level of the virus neutralization?

A.: This means the number of volunteers who developed the pre-set level of neutralizing antibodies. We will be able to discuss efficacy in several months when the major part of Phase III volunteers is immunized and information about the morbidity level among those vaccinated with our drug is available.

Q.: At what stage is the development of combined vaccine against flu and coronavirus?

A.: We are now actively evaluating the possibility of joint use of the CoviVac vaccine and registered influenza vaccines. Animal studies have already been partially completed, and the results of the joint use of the Flu-M and CoviVac vaccines will be published in the near future. We have already been working on other vaccines, and the interim results we have are very encouraging.

Q.: Is a platform for a rapid adjustment of the vaccine for new strains being developed?

A.: There is such a platform. After all, CoviVac was developed on the basis of a technology the Chumakov Center used earlier to create an inactive polio vaccine. A new vaccine based on the Delta variant is undergoing pre-clinical trials already. In principle, it is quite likely that coronavirus vaccines will eventually follow in the footsteps of flu vaccines - the strain changes every year but there is no need for constant re-registering.

Q.: At what stage is the development of a vaccine against the Delta variant?

A.: As we have said, the vaccine is being tested on animals, and we will be ready to submit the data to the Health Ministry as early as this fall. At the same time, we do not see any significant decline in the CoviVac vaccine's efficacy against the Delta variant. We are constantly monitoring the virus variants in circulation and will be able to rapidly modify the vaccine if its efficacy reduces in countering any new variants.

Q.: It was reported in June that the Chumakov Center applied for including CoviVac into COVAX program. Have you received a reply?

A.: Yes, we are in talks with COVAX and awaiting the results of clinical studies of the 60+ age group in order to complete the dossier.