“The immunogenicity data leave uncertainties regarding how long the protection provided by the inoculation lasts,” Anvisa stated in a note.
Anvisa now wants data from the studies conducted by the company on the administration of the extra shot, as well as the results obtained by the research. A meeting with Pfizer representatives on the topic has also been requested.
Anvisa says it has thus far received 27 notifications of suspected cases of GBS after immunization with vaccine AstraZeneca, in addition to three other cases with vaccine Janssen, and other four with CoronaVac, adding up to 34 occurrences.
The initial study will be carried out in participants who have already received the two doses of the inoculation, with an interval of four week between administrations, Anvisa noted. The booster shot will be administered 11 to 13 months after the second dose.