The Positivist Church of Brazil in Rio de Janeiro is documented as the one organised body still holding services, but no current membership or attendance figure for it was found in the sources checked for this record.
What would resolve this A current statement from the Positivist Church of Brazil itself, or an independent survey of its membership and attendance.
OpenSociology of religionEncyclopaedia Britannica editors, Encyclopaedia Britannica (online academic reference)