Sovereign 2, closer to starting clinical trials

Doctor of Science Vicente Vérez Bencomo, general director of the Finlay Vaccine Institute, belonging to the BioCubaFarma Business Group, affirmed in an interview with Granma that the so-called Sovereign 2 is an innovative vaccine, as it has no precedent among all those that are developed to face COVID-19 in the world

Cuban science will mark another milestone in the confrontation with COVID-19 when, in the next few days, a second vaccine candidate against the disease receives the corresponding authorization from the Center for State Control of Medicines, Equipment and Medical Devices (Cecmed), in order to starting the clinical evaluation phase.

Doctor of Science Vicente Vérez Bencomo, general director of the Finlay Vaccine Institute, belonging to the BioCubaFarma Business Group, affirmed in an interview with Granma that the so-called Sovereign 2 is an innovative vaccine, as it has no precedent among all those that are developed to face COVID-19 in the world.

Its novelty is that it is a conjugate vaccine, in which the virus antigen, the receptor-binding domain (RBD), is chemically bound to tetanus toxoid, he said.

–When talking about the virus antigen, does it mean that it is used in the new vaccine candidate?

–No, both Sovereign 1 and Sovereign 2, are molecular vaccines or subunit vaccines.

‘This implies that the vaccine antigen is a molecule that is a copy of the molecule present in the virus. To obtain it, it is necessary to have the genetic information of this viral protein, and from a process of genetic engineering, it is programmed in a cell of a higher organism called CHO.

“In this way, we are able to express the viral protein in a cell, which in this case constitutes the ‘factory’ to produce the viral antigen.

«The reprogrammed CHO cell produces the copy of the virus molecule, which is extracted and purified at the Center for Molecular Immunology (CIM).

“The rationale for the two Sovereign vaccines is that the viral protein, which constitutes the vaccine antigen, is the same molecule. There is a common process for both vaccines, which is obtaining the viral antigen, and the difference comes in what is done afterwards.

– Is there a history of conjugate vaccines in Cuba and in the world?

–This type of vaccine has been used, above all, in the prevention of bacterial infectious diseases.

«The first conjugate vaccine developed worldwide was against Haemophilus influenzae type b or Hib, a bacterium that causes childhood pneumonia and meningitis.

«Cuba finished developing and registered its vaccine against Hiben in 2004, the date from which it was included in the National Vaccination Program.

‘In ours, the Hib antigen was made from total chemical synthesis, which has been a worldwide scientific first to date. Today it is part of the Cuban pentavalent vaccine, of which more than 40 million doses have been produced for use not only in Cuba, but in other countries.

“We also have another conjugate vaccine under development by the Finlay Vaccine Institute, in this case against pneumococci (the bacterium that causes childhood pneumonia and meningitis). «Clinical trials in children aged 1 to 5 years have already been completed, proving its efficacy. It is currently in the productive escalation phase to be able to register it in a near period ». 

–What properties distinguish a conjugate vaccine, for example, from Sovereign 1?

–The known conjugate vaccines have two distinctive properties: they induce long-lasting immunity and the antibodies generated not only protect against the disease, but also prevent these bacteria from colonizing the oropharynx of the vaccinated. Faced with a viral infection, such as COVID-19, we hope to find similar qualities.

– Can you tell us what is expected in the planned clinical trials of Sovereign 2?

–Firstly, to demonstrate that it is a safe vaccine, based on the safety history of other previously used conjugate vaccines, in addition to achieving a powerful and long-lasting protective immune response, like Sovereign 1.

«Along with the above, we hope that immunity reaches the mucosa of the respiratory tract to prevent the entry of the virus, and it will be the vaccine candidate that we will propose to apply in the pediatric population.

“It is appropriate to mention that Sovereign 2 completed all the required research phases in experimental animals, demonstrating a powerful and effective immune response against the virus. Based on these results, Cecmed has been asked for authorization to start a phase 1 clinical trial in healthy adults, and we expect to receive approval in the next few days.

“In addition to its safety, in clinical trials we will evaluate which of the immunological properties we have opted for are confirmed in vaccinated subjects.”

–How far have we advanced with Sovereign 1?

–As we have explained on other occasions, Sovereign 1 is also a molecular vaccine, which contains the same molecule of the virus, in this case in a formula that contains two adjuvants, whose function is to potently stimulate the immune response.

«The first two formulations that were reported in the Round Table last August, successfully followed their passage through the clinical trial. The two doses were already applied to the study participants and the safety of the same could be verified, with very few adverse effects, all slight.

“In the coming weeks, phase 1 of the study will end with the analysis of the immune response of the participants. From this vaccine, we also expect a powerful protective immune response that is durable over time.

“Likewise, we are rapidly developing three other vaccine candidate formulations, which began the Phase 1 trial.“ With this we intend to select the best formulation in order to advance to higher stages of clinical trials.

“Both vaccine candidates are based on technological platforms for which there are precedents for vaccines in Cuba and in the world, aimed at other infectious diseases.

«It is worth noting that the clinical evaluation stage is not a formal stage, but rather the moment to assess and confirm the desired protective response in humans, it is the stage in which doses, treatment schedules, different age groups, and other aspects are evaluated .

“Therefore, terms of time that must be met are required to achieve these results and go through the different stages of clinical trials.”


  • On July 28, Soberana 1, the first Cuban and Latin American and Caribbean vaccine candidate against COVID-19, was tested for the first time in humans, which was an important achievement of Cuban science.
  • The name of the vaccine reflects the feeling of patriotism and revolutionary and humanist commitment with which it has worked, and also the commitment to the foundational, and when we speak of foundational, we are talking about the Commander in Chief, “said Cuban President Miguel Díaz -Canel last August, in a meeting with experts who have directly faced COVID-19.
  • The vaccine has been approached prudently, with moderation, without fanfare, said the Head of State, and warned then that more social responsibility had to be demanded to avoid outbreaks of COVID-19, and reach the final result of the vaccine in a better epidemiological situation.
  • The results of the study of the vaccine candidate will be ready for next January, and the scientists working on the materialization of the Cuban vaccine are making a great effort to start vaccinating the population in the first half of 2021.
  • This result is the result of the integrated work between the Finlay Vaccine Institute, the Center for Molecular Immunology and the Chemical and Biomolecular Synthesis Laboratory of the University of Havana.
  • It is a commitment to technological sovereignty in the face of COVID-19 in Cuba.
  • The Finlay Vaccine Institute is an institution with more than 30 years of experience in vaccine development. It is a leader in the use of outer membrane vesicle platforms (EMV).

source: Granma