RIO DE JANEIRO (REUTERS) - Brazil's government has not yet asked the United States for spare Covid-19 vaccines, according to two people with knowledge of the matter, despite Washington agreeing this week to send 4 million doses of AstraZeneca shots to Mexico and Canada.
The country's Senate leader says he has requested US help.
Brazil's coronavirus death toll, nearly 300,000, is second only to the United States, and its health system is buckling under a record surge in cases.
President Jair Bolsonaro, who has questioned the "rush" for vaccines, is under growing pressure to get a grip on an outbreak he once dubbed a "little flu."
He has been criticised for a slow and patchy immunisation programme, which has led to a lack of vaccine supplies in Latin America's biggest country.
Earlier this month, his government asked the Chinese embassy to help secure 30 million doses from China to ensure its vaccine programme does not grind to a halt.
Despite the United States agreeing this week to loan shots to Mexico and Canada, the Bolsonaro government has not yet asked Washington for vaccine supplies, said the two sources, who asked not to be named due to political sensitivities.
Neither the Brazilian president's office nor the foreign ministry replied immediately to requests for comment. The US State Department also did not respond immediately to questions.
US President Joe Biden has come under pressure from countries around the world to share shots, particularly its stock of AstraZeneca vaccines, which are authorised for use elsewhere but not in the United States.
The president of the Brazilian Senate, Mr Rodrigo Pacheco, said he wrote to Vice-President Kamala Harris asking the US government to allow Brazil to buy surplus vaccines. That, he said on Twitter, would help boost vaccination of Brazilians.
The AstraZeneca vaccine, which is the centrepiece of the Brazilian federal government's vaccine plan, has full regulatory approval in Brazil, meaning it could likely be used immediately.
This week, Mr Bolsonaro's political nemesis, former President Luiz Inacio Lula da Silva, used a high-profile CNN interview to ask the US government to share its vaccine stock with Brazil.
Mr Lula's comments - coming shortly after his graft convictions were annulled, allowing him to run in next year's presidential election - pose a challenge to Mr Bolsonaro, as any subsequent request could let his rival score political points.
Mr Bolsonaro's relationship with Mr Biden also got off to a rocky start after he waited nearly a month and a half to recognise the results of the US election last year.
Mr Bolsonaro enjoyed much warmer relations with Mr Donald Trump, Mr Biden's predecessor and a political role model for the Brazilian president.
Almost eight out of 10 Brazilians think the pandemic is out of control in their country and more than half are "very afraid"they will get infected with coronavirus, a new Datafolha poll said.