The government of São Paulo announced on Wednesday (16) that the application of the fourth dose of the vaccine against Covid-19 for the elderly over 80 begins on March 21. The decision follows a recommendation from the Covid-19 Scientific Committee in the state. The city of São Paulo decided to bring forward the start of immunization of this public to this Friday (18).
In this Thursday’s edition (17) of the Medical Correspondentfrom Novo Dia, neurosurgeon Fernando Gomes explained why the elderly need additional doses of vaccines against the new coronavirus.
Advancing age brings different impacts to the human body, including the ability of the immune system to function.
The aging process affects different types of immunity, due to a phenomenon called immunosenescencedefined as the dysregulation of immune function in the elderly. In addition to reducing the vaccine response, immunosenescence contributes to increased susceptibility to infections, cancer development and autoimmune diseases.
To receive the additional dose, the person must have received the third injection at least four months ago.
“In terms of organization and knowing the immune system and the response that we have on average to vaccines, it is a reasonable time for you to offer an additional stimulus so that the immune system will produce more antibodies and the cellular defense itself will be trained”, explains Gomes.
The allergist and immunologist from the University of São Paulo (USP), Brianna Nicolletti, explains that the need for reinforcements in immunization against any preventable disease through vaccines is only pointed out from the fall of protection in the face of a complete initial vaccination schedule.
“People considered protected from the most serious manifestations of the disease with the application of three doses of immunizing agent, at first, did not need reinforcement at this time. However, for populations at risk, immunosuppressed and elderly, it is already understood that a fourth dose may have a benefit four months after the last dose”, he says.
How does immunity induction work?
Vaccines against Covid-19 are developed using different technologies. Although each technology adopts a different methodology, the objective is the same: to stimulate the production of neutralizing antibodies that will recognize and eliminate SARS-CoV-2, the virus that causes Covid-19.
When vaccines are applied, they carry information about the new coronavirus to the body that will teach the body to produce specific defenses against the microorganism. Thus, if a vaccinated person is exposed to the natural infection, the defense mechanisms are ready to fight the virus – which reduces the number of hospitalizations, severe cases and deaths from the disease.
In addition, the immune system response is complex and goes beyond the action of antibodies. When vaccines are inoculated into the body, they also have an essential function of activating other defense cells in the body, the so-called T lymphocytes.
The cellular response generated by immunizers also involves memory cells of the immune system that remain in the body. Thus, when the individual comes into contact with the new coronavirus through a natural infection, they activate the production of antibodies that respond against the infection, mainly preventing serious cases, hospitalizations and deaths from the disease.
Basic care helps prevent Covid-19
Source: CNN Brasil
