The measure, which has already been adopted in Israel and Chile, is being analyzed by the Ministry of Health
Amid recently published studies and the new stages of the vaccination campaign against Covid-19, controversy is growing in the country and especially in social networks about the need to apply the third dose, or booster dose of the vaccine. The death of actor Tarcisio Mera, after being vaccinated with two doses, widened the discussion.
The procedure, which has already been adopted in Israel and Chile, is being analyzed by the Ministry of Health, but according to the ministry, it should take time to be incorporated into the National Immunization Program (PNI) – since Brazil needs to complete a two-dose or one-dose vaccination scheme.
At the end of July, the Department of Health announced that it would conduct a survey with 1,200 volunteers to assess the need for a booster dose for those who had taken two doses of Coronavac. The idea is to analyze the interchangeability of the vaccine produced in Brazil by the Butantan Institute with other immunizing agents, that is, the possibility of taking different vaccines.
Last Tuesday (10), the results of two clinical studies of immunogenicity released by the Chinese laboratory Sinovac on Coronavac, showed that in the group aged between 18 and 59 years, the third dose of Coronavac was applied six months after the completion of physical therapy. The (two-dose) regimen resulted in a three to five times greater immune response. Among subjects over 60 years of age, application of a booster dose eight months after the second resulted in a response that increased five to seven times. The articles are published in preprint form, that is, without review by other scholars.
On this week’s episode of FioCruz’s “CoronaFatos”, Renato Kfoury, an infectious disease scientist with the Brazilian Association of Immunizations, explained that the key at this time is to immunize the population of countries with the full two-dose vaccination program, or in the case of Janssen, in a single dose, as quickly as possible Possible, but it shows the importance of conducting studies to indicate the future of fighting the Corona virus with the use of vaccines. “Apart from CoronaVac, the whole world is thinking about the third dose. Some individuals have a worse immune response, and there are a group of people who are the first to lose the protection they developed,” says Renato Kfoury.
He points out that there are still insufficient studies to measure how long the antibodies produced by vaccines survive.
On Twitter, researcher Bruno Velardi, scientific director of the Cancer Brasil Institute, defended the application of an additional dose especially for the elderly. “Coronavac is a good vaccine. It has saved many lives. It is less effective than others in the elderly, especially. Populations most at risk. Revaccinating these elderly people with better vaccines is a duty. To deny it is political,” reads the post.
The director of the Couto Maia Institute, infectious scientist Ceuci Nunes stated that no immunizing agent is able to guarantee absolute protection against any disease. He wrote on Twitter: “Let’s remember one thing: No vaccine protects 100%, not just Covid 19. Older people and people with chronic diseases are more likely to suffer from vaccine failure.”
COVID-19 in petroleum
While some experts publicly defend that the country needs to discuss the possibility of a third dose – local health authorities are still waiting for more accurate data. Health Minister Aloisio Barbosa da Silva Filho highlights “We are monitoring the COVID-19 situation daily, with regard to the demand for care and hospitalization. In parallel, we continue to work tirelessly to advance vaccination.”
The secretary, however, stresses the importance of residents to maintain preventive care.
“The arrival of new batches has allowed vaccination. The entire health management team has dedicated itself so that we can as soon as possible receive the entire population of the immunized vaccine. It is still essential, however, for people to maintain that it is important that everyone continues to do their part. This is confirmed by the Minister of Health.
According to the municipality, the number of hospitals in the city, taking into account public and private hospitals, has not changed, compared to July and August. In July, the daily rate of hospitalization was 98 people. In August, the number was 95. Regarding the number of aid at the point of support, the municipality found an average of 104 daily aid in July. In August, taking into account the data up to the eleventh, there were 113 calls daily.
Third dose or overdose
The head of the Putantan Institute, Dimas Covas, explained on Wednesday (11) that there is confusion between a third dose and an additional dose, and that studies indicate the possibility of revaccination of the population to improve immunity.
People think that whoever takes the two doses should take a third dose to supplement immunity. This is not what we are talking about here. He explained that we are talking about revaccination. According to him, safety studies indicate two-dose vaccination, which does not require a third dose of the vaccine. As long as the virus spreads around the world, an extra dose of the vaccine could help fight Covid-19.
According to the President of Botantan, some countries have already started a revaccination program, such as Chile, Israel, the United States and Canada. This should also happen in Brazil, once the public has finished taking the two or one doses of the SARS-CoV-2 vaccine.
“The priority is to finish the vaccination schedule, which leads to herd immunity,” Dimas explained. He explained, “It is the collective immunity that will be able to resist the changes that may arise in the future.”
Third dose studies in progress:
Pfizer: The lab received permission from Anvisa in July to begin research into the effects, safety and benefit of a booster dose of the Comirnaty vaccine. In addition to Brazil, the study is being conducted in the United States and South Africa, and a total of 10,200 participants will take part in the three countries.
ASTRAZENECA: Part of the clinical trial calls for a single dose of the new version of the vaccine (AZD2816) to be given to people who have received both doses of the current version of AstraZeneca (AZD1222). Now, researchers are also conducting a pilot study to assess the need for a third dose after 12 months in people who have taken two doses of the immune system. Brazil is the only country, for now, that is conducting this type of study, according to the researchers.
UNIFESP: On Monday (16) researchers are set to begin a new study by the Ministry of Health to assess the need for a third dose of Covid-19 vaccines for those taking Coronavac.
BUTANAN: The institute is also preparing to start research that will evaluate the efficacy of a third dose of Coronavac in Brazil.
According to Anvisa, only three studies were approved in Brazil to investigate additional doses, two by AstraZeneca and one by Pfizer. Responsibility for the progression of studies rests with the sponsoring laboratories for each research.
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