Anticipation of booster against Covid is not based on science, doctors say

For infectious diseases, the decision of the state of São Paulo to bring forward the booster dose of the Covid vaccine has no scientific justification. The announcement was made this Thursday (2) and was due to the emergence of the omicron variant and the proximity to the end-of-year festivities.

Before, São Paulo residents should wait five months after the second dose to receive the booster of the immunizing agent. Now the wait is down to four months.

The application start timetable varies by municipality. In the city of São Paulo, the new measure takes effect from this Friday (3) — the immunizing agent from Pfizer will be used, regardless of which product has been applied in the primary vaccine schedule.

Renato Kfouri, pediatrician and director of SBIm (Brazilian Society of Immunizations), states that “there is no evidence to do this in younger individuals”.

“We have data that show there is a loss of protection over age 50 — and over time. This loss is faster by vaccine and age, so Coronavac loses protection first than AstraZeneca, so how seniors lose first,” he explains.

Kfouri also claims that data on loss of protection against the coronavirus for people under 50 years old do not exist in Brazil.

However, the doctor emphasizes that taking the booster even at a younger age and in the shortest possible time should not harm people. “Everyone will need the reinforcement, but in this shorter interval I don’t see any advantage. Making a reinforcement with an interval of five months, favoring those who need it most, is a better idea”, he says.

“The immunization program is made with strategies, recommendations that are not changed all the time and with evidence. At the Ministry of Health, the calculation we made is that by the end of the year we would be offering a booster dose for everyone over 50 years old five months after the second dose,” he says.

As for omicron, Kfouri says there is no evidence, at least for now, that the new variant requires a change in the vaccination schedule.

“I don’t think it’s an attitude that will bring benefits, it only serves to create confusion. People may ask themselves ‘why is São Paulo doing this?’. It seems that they always want to create a program that is different from the rest of the country,” he adds.

This Thursday, after the announcement by the government of João Doria (PSDB), members of the Ministry of Health reported that currently the folder does not intend to recommend reducing the dose range from five to four months. So far, these members of the folder say, there are no proven benefits of this reduction.

When informing the new calendar, the government of São Paulo says it took “into account that São Paulo is a gateway, via ports and airports, for people from all over the world and Brazil does not yet have the obligation to present proof of a complete vaccination schedule for travelers”.

Raquel Stucchi, a professor at Unicamp (State University of Campinas) and a consultant at the SBI (Brazilian Society of Infectology), agrees with Kfouri that there is a lack of evidence for this anticipation of reinforcement.

For her, it has already been observed by scientists that people up to 50 years old maintain good protection for up to five months, which starts to decrease after 60 and 70 years of age. “Flashing it another month seems like a waste of vaccine,” she says.

According to Stucchi, it would be more recommendable that the state donate doses to countries that need it most.

“Another attitude that the government of the state of São Paulo should take is to look for those who did not take the first dose and those missing the second dose. Efforts should be concentrated for that and not keep changing the policy”, he says.