Brazil's death toll from Covid-19 surpassed a quarter-million Thursday, a year after the first case was confirmed in the country, which is struggling with vaccine shortages and a devastating second wave.

The new coronavirus has now killed 251,498 people in Brazil, according to health ministry figures -- the second-highest toll worldwide, after the United States, where the number passed half a million Monday.

This has been the deadliest week yet of the pandemic in Brazil, with a daily average of 1,149 deaths over the past seven days, according to the ministry's figures.

The news came a day before Brazil marks one year since its first confirmed case of the virus, a Sao Paulo businessman returning from a trip to Italy.

Since then, the virus has spread across the sprawling South American country with dire effectiveness.

It has hit especially hard in Brazilian cities' impoverished "favelas," among indigenous communities with vulnerable immune systems, and in the Amazon rainforest city of Manaus, where there have been haunting scenes of mass graves and patients suffocating to death with no oxygen.

President Jair Bolsonaro has meanwhile flouted expert advice on managing the pandemic at every turn, railing against lockdowns and face masks and instead touting the malaria drug hydroxychloroquine despite a series of studies showing it is ineffective against Covid-19.

His government now faces criticism for failing to secure more vaccines.

The hard-hit country began vaccinations in mid-January with Chinese-developed vaccine CoronaVac and another developed by Britain's Oxford University with British-Swedish pharmaceutical firm AstraZeneca, both of which require two doses.

About six million Brazilians have received a first dose, and 1.3 million have received two.

But the government is far off-pace to meet Health Minister Eduardo Pazuello's pledge of vaccinating all Brazil's 212 million people by the end of the year.

Shortages have forced some key areas to temporarily halt their vaccination drives, including the cities of Rio de Janeiro and Salvador.

A workers wearing a protective suit and carrying an umbrella walks past the graves of COVID-19 victims in Manaus, Brazil -- the country has surpassed 250,000 deaths
A workers wearing a protective suit and carrying an umbrella walks past the graves of COVID-19 victims in Manaus, Brazil -- the country has surpassed 250,000 deaths AFP / MICHAEL DANTAS

Federal health regulator Anvisa this week approved the vaccine from US pharmaceutical firm Pfizer and German partner BioNTech for widespread use.

However, Brazil must first reach a deal to buy it.

Negotiations with Pfizer have stumbled over who would be held liable for any side effects, with vaccine-skeptic Bolsonaro warning the shot could "turn you into an alligator."

"It's very sad. A lot of people are still dying," said pensioner Dayse Pereira after getting vaccinated at a drive-through immunization clinic in the capital, Brasilia.

There are various things driving the second wave in Brazil, said epidemiologist Mauro Sanchez of the University of Brasilia: social distancing fatigue, delays in securing more vaccine and contradictory messages from the authorities.

"It's largely the result of the example set by our political leaders," he told AFP.

Meanwhile, Brazil has become "anaesthetized" to hundreds of people dying every day of Covid-19, he said.

Brazilians have largely gone back to life as normal, packing bars, buses, beaches and clandestine parties.

Some areas have tightened curfews or other restrictive measures, such as economic capital Sao Paulo and the northeastern state of Bahia.

However, the federal government has never implemented a nationwide social distancing response.

Experts warn that is enabling the virus to circulate, creating a greater risk of more-contagious variants, such as the one that emerged in Manaus and is now spreading fast.