Doctor remembers that reinforcement of the immunizer is essential, and that patients will only achieve the defense expected in the studies two weeks after taking the second dose
Protagonists in the immunization of Brazilians against Covid-19, as Oxford vaccines e do Butantan Institute are applied in two doses within the current National Immunization Plan. According to the package insert, the English technology immunizer needs the booster within eight to twelve weeks, and the Chinese technology immunizer should have the last dose applied within 14 to 28 days. The correct immunization interval is essential for vaccines to be considered effective, and those who only took the first dose are not immunized. “The first dose is stimulating the immune system, but we cannot quantify how much that person gets from partial protection, this is not a known thing. You consider that it has the benefit of protection only after the second dose ”, explains the director of the Brazilian Society of Immunizations (SBIm), Dr. Mônica Levi. She recalls that the concept of “half protection” does not exist, and that the immunization provided for in the studies is considered just two weeks after the application of the last dose of the immunizer, regardless of which laboratory it is.
When should the second dose not be applied?
There are two specific cases in which the second dose of the vaccine should not be applied within the regular range: if the patient has an extreme allergic reaction to the immunizer – which is rare – or if he contracts the disease before receiving the booster. According to the expert, in the case of extreme allergies, the patient should not receive the second dose at any time and should double the care with regard to Covid-19, since he will not have adequate protection against the disease. She recalls that there are no records of such reactions in the country so far. People who are infected with the new coronavirus between the first and the second application must wait 30 days after the onset of the disease to be able to increase the dose.
Delay or take too soon
Those who are able to take the second dose and, for whatever reason, have delayed the vaccine term, should provide a boost to the immunization immediately. “What happens is that the person goes on longer without developing the maximum protection that they can have against the disease. The sooner she completes the scheme, the better, ”recalls Levi. Some Brazilian municipalities have systems that only allow scheduling by those vaccinated within the specific period in which the booster must be taken. If someone mistakenly receives the second dose ahead of time, they will have gone to the vaccination line in vain. “If you take the second dose before the minimum period, in a week, ten days, you have to disregard this vaccine and make another dose on the correct date”, explains the doctor.
Vaccine country without second dose reservation
To speed up vaccination in Brazil, a technical report issued by the Ministry of Health on March 21 allowed all doses of CoronaVac in stock to be used to vaccinate as many people as possible without reservation for the second dose. The request for this action had been made in January by the government of São Paulo, but was denied by the Health Ministry at the time. According to the Ministry, the situation has changed because the country now has sufficient production speed to guarantee the second dose within the acceptable timeframe. As the Oxford vaccines have a longer interval between the two doses, they were already being applied without reservation in the country. So far, there is no record of lack of vaccine booster anywhere in Brazil.
Single dose vaccine facilitates logistics, but is not considered “better”
So far, only the vaccine developed by Janssen, the pharmaceutical arm of the American company Johnson & Johnson, has application in a single recommended dose in the world. This is because the study that developed it evaluated from the beginning how the vaccinees’ response to just one dose would be, which was not done with other immunizers. “We have scientific evidence of how effective it is with just one dose, which is why we make a single dose of this vaccine. It may be that a vaccine appears that needs three doses and is also an excellent vaccine. What determines the number of doses are the studies and the correlation with the protection she evaluates ”, explains the doctor. She stresses that, despite the advantages in terms of logistics, time and cost, this does not mean that the Janssen immunizer better immunizes the population compared to other vaccines applied in the world. The vaccine had emergency use approved in the country by Anvisa last Wednesday, 31.
Three immunizers have emergency use approved by the National Health Surveillance Agency (Anvisa), that of the Oxford / AstraZeneca university, produced in Brazil by the Oswaldo Cruz Foundation, and that of Sinovac, produced by the Butantan Institute, and that of Janssen, developed only in Brazil. outside. The Pfizer / BioNTech vaccine has been definitively used by the agency, but it has not been applied en masse in the country so far. The forecast of the federal government is that in the next two months the daily number of vaccinees will be one million people.