Some vaccines may require third dose – ANVISA president

RIO DE JANEIRO, BRAZIL – The director-president of Brazil’s health regulatory agency ANVISA, Antônio Barra Torres, said he believes that some of the available vaccines against Covid-19 will require a third dose. Invited by the Commercial Association of Rio de Janeiro (ACRJ) for an online talk on July 13, Barra Torres answered questions forwarded by viewers.

“I believe that some vaccines will need a third dose. It’s still hard to say which one,” he said, stressing it’s his personal assessment. “It’s being studied all over the world. The whole world is looking into it, and the goal is to secure safe and longer-lasting immunization,” he added.

ANVISA is responsible for authorizing the use and approving vaccine package inserts in Brazil, which contain information about the dose regimen. For now, no immunizers provide a three-dose administration scheme. Barra Torres stressed that all ANVISA-approved vaccines are effective and that people may rely on any one available at health centers. “The best one is the one in your arm,” he said.

To date, vaccines from AstraZeneca/Oxford, Pfizer/BioNTech, Coronavac, and Janssen have been granted either definitive or emergency approval. The first three are two-dose and the fourth is a single-dose immunizer. Also requiring two shots, the Sputnik V and Covaxin vaccines have been granted import authorization, albeit with limitations.

Pfizer last week announced that it is developing a third dose of its Covid-19 vaccine.

The Chilean government also recently reported that it is studying the possibility of distributing a booster dose. The country was registering a surge in cases although 61% of the target public had been immunized with two doses.

Rio de Janeiro mayor Eduardo Paes has also raised the prospect of a third vaccine dose.

Combination

ANVISA’s director-president also analyzed the feasibility of combining vaccines from different laboratories to fight Covid-19.

“Regulatory activity is not the driving force behind this process. It is the train caboose. We are pulled by the developer or the researcher that presents us with its conclusions so we can assess and endorse them. We are talking about an interaction of immunobiologicals of different origins and platforms. That comes from the scientific community. We are currently monitoring some situations that may in the future be subject to our opinion,” Torres said.

He recalled that decisions in this direction have been taken by certain countries in some cases. In Brazil, the situation has been occurring with pregnant women.

The AstraZeneca vaccine was administered to some of them and later suspended by the Ministry of Health due to a suspected adverse reaction case. Pregnant women who were administered the vaccine were later authorized by the Ministry to receive a second dose from Pfizer.

Torres said that measures to prevent the disease are well known: masks, social distancing, hand hygiene, and the vaccine. “Having the two vaccine doses doesn’t mean one can immediately stop wearing a mask,” he added.

Source: Exame