The number of deaths related to Covid-19 has passed 500,000 in Brazil, the second-highest in the world, as experts say the outbreak could worsen amid slow vaccination and the start of winter.
The virus continues to spread as President Jair Bolsonaro refuses to back measures like social distancing.
The health institute Fiocruz says the situation is "critical". Only 15% of adults are fully vaccinated.
Congress is investigating the government's handling of the pandemic.
President Bolsonaro has been heavily criticised for not implementing a co-ordinated national response and for his scepticism toward vaccines, lockdowns and mask-wearing requirements, which he has sought to loosen.
The president has said the impact of lockdowns on the economy would be worse than the virus, and insists he has done all he can to buy vaccines from several countries.
But the opposition accuses him of delaying vaccine orders for political reasons, as he has consistently played down the severity of the pandemic.