With the start of the immune boosting campaign against Covid-19, scientists diverge on the use, or not, of the Butantan vaccine in elderly and immunosuppressed patients
Brazil officially starts the application of the third dose of vaccine against Covid-19 next week. Although some capitals have anticipated the reinforcement schedule, the forecast is that the new stage of immunization starts in all municipalities on September 15th, after determination of the Ministry of Health. The decision to apply an additional dose is based on clinical analyses, which show a progressive decrease in the immune response against the coronavirus over time, especially in the elderly and immunosuppressed patients. Therefore, the recommendation of the federal government is that people with over 70 years receive the booster six months after the last dose of the vaccine schedule (second dose or single dose) and people with high degree of immunosuppression receive the application 28 days after the basic regimen. In the latter case, priority is given to “patients undergoing chemotherapy, transplants, people living with HIV, who use steroids or immune response-modifying drugs, as well as patients on hemodialysis or with chronic inflammatory immune-mediated diseases.”
According to a technical note released at the end of August by the Ministry of Health, the immunizing agent used for this new application “should preferably be from the messenger RNA platform [Pfizer] or alternatively, viral vector vaccine [Janssen ou AstraZeneca]”. However, even with the recommendation of the National Immunization Program (PNI), some States, such as São Paulo and Rio de Janeiro, decided to include the CoronaVac no role of alternatives for or immune booster. On Monday, 6th, the first day of the new stage of immunization in São Paulo, 12,607 people received the third dose in São Paulo cities, with 99.2% taking CoronaVac, 0.3% AstraZeneca and 0.1% the Pfizer. The government of São Paulo claims that the exclusion of Butantan Institute vaccine was motivated by a “political, not technical decision” and reinforced the safety of the use of the immunizing agent for the third application. “We should do a booster dose with the vaccines that are available., regardless of who took one type of vaccine or another”, said João Gabbardo, Executive coordinator of the Scientific Committee of the State.
The decision of São Paulo, however, is not well regarded by health specialists. The director of the Brazilian Society for Immunization (Sbim), Renato Kfouri, argues that the best option is that the vaccine boost is made with the vaccine from Pfizer, which showed superior results for immunization of the elderly. For him, in the absence of the immunizing agent, the secretariats should use the compound of AstraZeneca. “São Paulo is not using the best vaccine for the population, it is preferring the use of an immunizer whose immune response is lower. Of course it will give a boost, there is no doubt that even with CoronaVac you have an increase in immunization, but this increase in the level of antibodies it can be bigger”, explains the immunologist. In his view, in addition to causing confusion for the population, these “mismatched conducts” between governments should drive “vaccine sommeliers”, people who choose the brand of immunizing, a reality that already happens in the country. “Many people are turning down CoronaVac for the third dose. This is already a fact. Any communication noise will harm the campaign. the ministry [da Saúde] say one thing, São Paulo does another, Rio de Janeiro does another.”
CoronaVac: alternative or contraindication?
The divergence of understanding between the government of São Paulo and the Ministry of Health on the adoption of the Instituto Butantan vaccine as a booster dosage generated a series of doubts in the population, which questions: a CoronaVac should be used for the third dose? For the infectologist Marcelo Otsuka, the immunizing agent can be used to boost the vaccine against Covid-19. According to him, preliminary clinical analyzes show that the new application does not elevate or bring new adverse effects to the vaccine, which is positive. “Is there a problem with taking the third dose with CoronaVac? We have few studies, but not at first. The only one we have is a Chinese study that showed that the third dose increased 2.5 times the amount of antibodies compared to those who took two doses. But, in real life, with large groups, we don’t have analyzes of boosting with any of these vaccines”, points out Otsuka.
According to the infectious disease specialist, even with the lack of conclusive data, CoronaVac is “welcome and welcome” for the third dose. He points out that the direction of the Ministry of Health, defining the Pfizer vaccine as a preference for the booster dosage, happens because the folder was based on a survey carried out by the North American pharmaceutical when deciding on the need for the booster vaccine. However, this does not preclude the use of other immunizing agents available for application in the country. “There is still a lack of robust studies that corroborate both the association of vaccines and the effectiveness of the third dose. The data we have suggests that it is. [é eficaz], and that there is no increase in side effects, so it’s already a big deal.”
In addition to the doubts about the adherence or not of CoronaVac in the list of vaccines for the third dose, another frequent question is about the interchangeability of immunizers. That is, the use of drugs from different laboratories for vaccine booster. the state of Rio de Janeiro announced that it will opt for the heterologous vaccination scheme. That is, whoever took the two doses of the Butantan vaccine must receive a new application with a compound from Pfizer or AstraZeneca, and vice versa. About this possibility, Marcelo Otsuka also points out that there is still a lack of studies on the subject, but he says that, considering the current knowledge about vaccines, the mixture should not bring risks. “Is there a problem with taking the other vaccines? Not at first. Having trouble taking the third dose of CoronaVac? Not at first either. What is the best option? We still don’t know”, admits the infectious disease specialist.