The combination of different vaccines can be a strategy to broaden the population vaccination coverage within the context of global shortage of Covid-19 vaccines. However, with few available studies on this subject, where most of them are about the AstraZeneca and Pfizer vaccines only, it is hard to establish interchangeability guidelines.

Aiming to fill the gap, a study conducted by Oswaldo Cruz Foundation (Fiocruz) will evaluate the immunization effects with combinations of the CoronaVac and AstraZeneca vaccines, which are produced in Brazil. The work will be financed by the Science and Technology Department of the Health Ministry (Decit/MS) and will cover the five regions of the country.

The project coordinator and researcher for the Immunopharmacology Lab of Oswaldo Cruz Institute (IOC/Fiocruz), Adriana Vallochi, emphasizes that the vaccine combinations can generate an intense and lasting immune response. Nevertheless, it is not possible to establish interchangeability protocols without studies that confirm the effectiveness of the vaccination schemes.

“There is no published data about the interchangeability of the CoronaVac and AstraZeneca vaccines yet. The results of the project must clarify if the protocols with the combination of these vaccines induce protection and immunity durability. This information can contribute to the planning of the PNI [National Immunization Program], pointing out more effective schemes and enabling the replacement of vaccines in case one of the vaccines’ doses are lacked”, emphasizes Adriana.

Altogether, seven Fiocruz units will work on the research. With a national coordination by the IOC, the project will be developed in partnership with the National Institute of Women, Children and Adolescents Health “Fernandes Figueira” (IFF/Fiocruz), Institute of Technology in Immunobiologicals (Bio-Manguinhos), Rondônia Fiocruz, Mato Grosso do Sul Fiocruz, Gonçalo Moniz Institute (Bahia Fiocruz), and Carlos Chagas Institute (Paraná Fiocruz). The initial phase of the project had the support from the Fiocruz’s Vice Presidency of Research and Biological Collections. In the IOC, the Labs of Immunopharmacology, Biotechnology and Physiology of Viral Infections and Research on Thymus will participate. The study will also have the partnership of the Central Public Health Laboratories (Lacens) of the states.

Research objectives The main objectives of the research will be to assess the immunogenicity—the capacity to stimulate the immune response—and the safety of the vaccine combinations. In order to do so, 1,400 volunteers will be followed, divided into five groups: vaccinated with CoronaVac in the first dose and AstraZeneca in the second one; with AstraZeneca in the first application and CoronaVac in the second one; with the regular schemes of two doses of these vaccines; and unvaccinated.

Source: Fiocruz News Agency (AFN)