Vaccines: from research to immunization

By Tiago Varella, from Agência Einstein - Researchers from various countries are engaged in a global effort to develop an immunizing agent capable of producing antibodies in humans and neutralizing the novel coronavirus. While this endeavor is encouraging, the production process is complex and generally lengthy until a vaccine is ready and approved by the regulatory agency.  

“Developing an immunizing agent requires a long period of studies, which involves research to identify the part of the virus or bacteria that is immunogenic, that is, that produces antibodies, and tests that can guarantee the safety and efficacy of the vaccine against diseases,” explains Alfredo Elias Gilio, medical coordinator of the Immunization Clinic at the Albert Einstein Israelite Hospital.  

In order to stimulate the immune system to fight the virus or bacteria and prevent new infections, the vaccine production process can have different approaches. One of them is related to the removal of a part of the microorganism, such as the surface protein. With this, the collected composition will activate antibodies to neutralize the protein present in this layer of the harmful agent.  

The other method involves weakening the virus and bacteria, rendering them incapable of causing disease and controlling their replication cycle. The immune system then begins producing cells to defend the human body against the invasion of microorganisms.  

Some antibodies produced from vaccines don't last very long in the body, so repeated doses are needed periodically. Other vaccines, however, require fewer doses because the immune system develops a memory of how to react to and defeat viruses and bacteria.  

“Immunization is fundamental to reducing cases of infection and even eliminating some diseases. In Brazil, vaccination campaigns have been quite effective in eradicating measles, smallpox, and polio,” adds infectious disease specialist Hélio Arthur Bacha, technical consultant for the Brazilian Society of Infectious Diseases. Following the vaccination schedule therefore guarantees immunization against various diseases and, consequently, greater health and well-being for the population.