Covid-19: Brazil health regulator questions Minister over booster shot in adults, Janssen second dose

RIO DE JANEIRO, BRAZIL – The Brazilian Health Regulatory Agency (ANVISA) on Thursday, November 18, questioned Minister of Health Marcelo Queiroga about the technical elements used to authorize the third dose of the vaccine against Covid-19 in fully immunized adults in the country.

The measure, announced by the Minister this week, is currently applied in states such as São Paulo and Rio de Janeiro, and covers people who have been vaccinated with two doses at least 5 months ago.

The regulator also wants to know the reasons behind the introduction of a second dose for people immunized with Janssen’s single-dose vaccine. ANVISA wants answers to the following questions:

• What studies were used to support the decision to administer a second dose as part of the primary regimen and a third dose as a booster to people vaccinated with one dose of the Janssen vaccine?
• Did studies have a follow-up after the second and third dose of at least 2 months for safety evaluation?
• What was the efficacy demonstrated after the second and third dose?
• Were the safety results similar to those achieved after the first dose? What differences were found?
• Will a different strategy for monitoring adverse reactions be adopted for the new vaccination scheme adopted? If yes, what?
• What will be the vaccine developers’ liability in the monitoring and pharmacovigilance of this implemented vaccine schedule?

In a press release, ANVISA states that the Ministry of Health’s explanations are required “under the sanitary point of view, particularly regarding the monitoring of the use of the new vaccine schemes in Brazil.”

On Tuesday, ANVISA technicians were surprised by Queiroga’s announcement on booster doses and changes in the administration of the Janssen vaccine because they had not been consulted to assess the effectiveness of the new route taken by the Ministry to protect Brazilians against the coronavirus.

In practice, ANVISA was relieved of its duties, which are to regulate, control, and supervise products and services that involve risk to public health.

In a previous statement, the agency had stressed that countries such as the United States, Canada, Indonesia, Great Britain and Israel, in addition to European Union members and other international organizations “submitted the strategy [booster dose] for prior assessment by their health regulatory authorities,” which was not the case in Brazil.

According to ANVISA, the available data point to decreased immunity in some populations, even if fully vaccinated over time. “The Agency has been monitoring the decisions of other countries on booster vaccination, as well as the results of effectiveness studies conducted by Fiocruz, which point to the need for the booster dose.”

However, ANVISA says that it monitors the effectiveness and safety of the booster dose of vaccines in use in Brazil, based on scientific studies, along with the vaccine manufacturers.

When emphasizing that this is its job, ANVISA points out that only Pfizer and AstraZeneca have so far requested a change in their vaccine schedule. Currently, the administration of the substances is performed in two stages, and the change requests under review by the agency seek authorization for a third dose.

With respect to Janssen, ANVISA says that based on opinions of other health regulators, the vaccine can only be used as a booster dose and not as a second dose, as announced by Queiroga. The agency is waiting for Janssen’s manufacturer to submit studies on the efficacy and safety of the booster dose to consider the measure.