The state of Mato Grosso do Sul, the municipality of Botucatu (SP) and Volta Redonda (RJ) started to apply the fourth dose of the vaccine against Covid-19 in elderly people aged 60 years and over this week.
At the same time, the states of São Paulo, Espírito Santo, Rio Grande do Norte and Acre are also considering starting the application of a fourth dose.
Israel also maintains a fourth-dose vaccination schedule for immunosuppressed people, healthcare professionals and the elderly.
In the United States, immunocompromised people are already eligible to receive the dose under the recommendations of the Centers for Disease Control and Prevention (CDC).
The vice president of the Brazilian Society of Infectious Diseases and professor at Unesp, Alexandre Naime, told CNN that the study in Botucatu began when there was a change in behavior after the arrival of Ômicron.
“In mid-December, when some elderly people, fully vaccinated, over 70 years old began to present moderate or severe conditions and began to need hospitalization”, he explained.
The additional dose of the immunizer was released as a measure to combat the pandemic by the Ministry of Health (MS) on December 20, 2021, which recommended the extra dose only for immunosuppressed people over 18 years of age and the elderly population.
According to a technical note from the folder, the Pfizer vaccine, using a messenger RNA platform, should preferably be used, and alternatively, the viral vector immunizer, from Janssen or AstraZeneca, can be applied.
What is known about the 4th dose of the vaccine
The duration of immunity is shorter in people with immunological weakness and, therefore, boosters can extend immunity further and maintain a high level of long-term coverage in patients who receive the additional vaccine, as explained by the president of the Minas Gerais Society of Infectious Diseases. (SMI), Estevão Urbano, at CNN
A survey involving scientists from the UK, USA and France indicated 40% of immunocompromised people managed to generate fewer antibodies than healthy people after two doses of vaccine, justifying the need for boosters. More robust research is underway to assess the effectiveness of the extra booster, particularly for immunocompromised people.
In January, an Israeli study found that the fourth dose of the vaccine can increase the number of antibodies fivefold. The result was obtained one week after the application of the immunizer.
According to Urbano, “the logic is this: for those individuals who have a shorter immunity, it is necessary to apply a booster dose to maintain adequate immunity for longer periods”, he said.
The Ministry of Health in Brazil follows the recommendation of the Prioritization Roadmap of the World Health Organization, which points to the recommendation of the booster dose only for priority groups, who received the last dose in the period of four to six months.
Fourth dose for the general population
Now, some states, such as São Paulo, are evaluating the possibility of applying the fourth dose to all people.
However, in an information note, the Ministry of Health states “that so far there are not enough data in Brazil to recommend a fourth dose for the general population, except for immunocompromised patients.”
The text, signed by the Extraordinary Secretary for Combating Covid-19, Rosana Leite, says that “before we move towards new indications in the calendar of the National Plan for the Operationalization of the Covid-19 Vaccine (PNO), it is necessary to understand the epidemiological scenario with greater detail regarding hospitalizations, deaths and infections by Covid-19 among certain age groups and their relationship with vaccination status (vaccinated vs unvaccinated).”
By telephone, the folder informed the CNN that “the matter is still under discussion and any news will be disclosed by the press office as we always do about new guidelines.”
However, the governor of São Paulo, João Dória, said on Wednesday (9) that the state will maintain the application of the fourth dose regardless of the recommendation of the Ministry of Health.
“Advancing in the second dose, we can advance in the booster dose, in the fourth dose, following an order of age group. […] we are going to adopt the fourth dose in São Paulo, regardless of whether or not there is a recommendation from the Ministry of Health”, he said at a press conference.
In January, Chile began to apply the fourth dose to the population over 12 years of age who are immunosuppressed and should begin the extra immunization of healthy people this month.
In Israel, the government is also studying the application of the booster to the population over 18 years old who has recovered from Covid-19 or who have received the third dose after a period of five months.
The debate on the possibility of applying the fourth dose has expanded within the scientific community — however, there is still no consensus on the real benefits of the booster, as explained by Estêvão Urbano.
Experts say that it is not yet time to give a fourth dose to the general population
The director of the Brazilian Society of Immunizations (SBIm), Renato Kfouri, said in an interview with CNN that “there is insufficient evidence to recommend recommending a fourth dose to the healthy population.”
According to Urbano, the booster dose for immunocompetent individuals (general population) is a lively debate, but it needs more robust studies to be indicated.
“Some states have already started to vaccinate the elderly and health professionals with the fourth dose, but still on empirical bases, without more robust evidence from the literature”, he points out.
However, he comments that the discussions regarding the fourth dose at the national level will take place after the clarification of the studies. “[Hoje]they are individual definitions according to the vision of public policies and the vaccination system of each state”, says Urbano.
Naime points out that extra immunization for the general population is not on the agenda because there is not enough evidence.
For Kfouri, “there is no need for states and municipalities to make a decision to vaccinate and carry out programs that are separate from the Ministry’s data.”
“This creates conflicts, as usual. It doesn’t help, it’s not good, and there’s no evidence,” she points out.
The director of SIBm points out that “whoever wants to use the vaccines they have, is failing to give the dose to someone.”
“What the federal government distributes are vaccines for the primary regimen and the first booster four months later. So, there are no doses to be given and whoever is doing it with the doses they have is because they are vaccinating poorly, other populations should be a priority”, comments Kfouri.
In the technical note released by the MS, the text says that the literature has shown that a booster dose has been shown to be useful tools to improve the immune response against the Ômicron variant.
And despite this discussion, the Ministry of Health emphasizes that completing the vaccination schedule with three doses is essential to reduce the number of deaths.
“Raising the population’s awareness of the need to complete the primary vaccination schedule and booster doses, especially in the most vulnerable individuals, is of paramount importance,” says the statement.
All experts agree with the MS guidance. Urbano says it is more important to go ahead with the application of the third dose.
“Even because, there is no consensus in the scientific community on how and when in which period the city should be given a new dose for those who already have three doses, except for the immunocompromised. What is within a scientific logic is to advance the third dose for all those who have not yet taken it”, he comments.
Naime believes that “in national terms, it is not time to talk about an additional application of the fourth dose when we have only 24% of people vaccinated with the third dose.”
However, the vice president of SBI says that in regional terms there are some municipalities that have advanced vaccination and can benefit from the fourth dose in the elderly.
“It is more important that the vaccinated population is on the third dose. However, in regional terms, in municipal terms, the realities are very different. So, it is obvious that the measures also need to be different”, says Naime.
Kfouri says that the country has an “enormity of people who have not taken the third dose and who need to take it. There is no point in discussing a fourth dose at this time.”
He also states that SBIm is following up with the Ministry in the Technical Chamber, hospitalization rate in different age groups due to vaccination.
“When we notice that there is some loss of protection for those who have three doses, the recommendation [da quarta dose] can be done. At the moment, there is no evidence”, he warns.
For Urbano, the fourth dose of the vaccine could be a possibility in the future. “If we had to make a cut-off point, most people in the scientific community would tend to think that, possibly, booster doses will be needed at periodic intervals for which it is not known exactly what that time would be”, he concludes.
Kfouri says that when it becomes necessary, the immunizer will be updated. “We can suddenly have more up-to-date vaccines and we should not rush into a decision like this”, he highlights.
With the advancement of Ômicron, some pharmaceutical companies have already started to produce the updated vaccine.
The CEO of pharmaceutical Pfizer, Albert Bourla, said in January that a specific vaccine against Covid-19 for the Omicron variant will be ready in March.
“We are working on a new version of our vaccine, a version that will also be effective against Ômicron, not that it is not effective against the other variants, but also against Ômicron,” Bourla told CNBC.
“The hope is that we’ll get something that has much, much better protection, particularly against infections, because protection against hospitalizations and serious illness is satisfactory now with the current vaccine, as long as you get the third dose.”
(With information from Fábio Munhoz and Lucas Rocha, from CNN)
Source: CNN Brasil
