Brazil's Covid-19 outbreak has reached new highs, driven by the spread of emerging coronavirus variants.
The Latin American nation of more than 211 million people was battered by one of the world's most intense Covid outbreaks last summer as death rates raged out of control for months.
Yet while global caseloads worldwide have receded in recent weeks, Brazil has again found itself setting new domestic records, with its outbreak as bad as it has ever been.
Brazil has already identified one new variant that has spread alarm across the world, and epidemiologists have warned that the scale of infection in such a large population risks spawning further dangerous mutations.
Some 8,224 Brazilians died of Covid last week in the country's biggest seven-day death toll.
Intensive care wards are close to buckling, with beds more than 80 per cent full in 18 of the nation's 26 states. Beds in nine of those states are more than 90 per cent full.
Eduardo Pazuello, the health minister, last week admitted new strains that are easy to catch had made controlling the pandemic more difficult.
"The mutated virus has three times more contamination capacity, and the speed can surprise governors in terms of structure and support. This is the reality we have today in Brazil," he told state governors, according to CNN.
Doctors have called for the immediate imposition of new lockdown and distancing rules to try to check the spread.
"In this scenario, if nothing is done, by March, people will be fighting for both hospital beds and graves in the cemetery," Domingos Alves, the director of the Health Intelligence Laboratory at the University of São Paulo in Ribeirão Prêto told the Washington Post. "We are going to need to open new graveyards to bury the bodies."
The Brazilian variant known as P1 was first found in the northern city of Manaus and had spread to 30 countries by the start of this month.
It is thought to be more contagious than the original strain of Covid and also shares a key mutation with the South Africa variant – called E484K – which is thought to evade the antibody response triggered by vaccination or natural infection.
With so many people infected in Brazil, other variants could arise, scientists fear. Miguel Nicolelis, an epidemiologist and neuroscientist at Duke University, told the Post: "If Brazil does not control the virus, it will be the largest open laboratory in the world for the virus to mutate.
"It could not only be the epicentre of the pandemic, but the epicentre of the dissemination of more lethal and infectious variants. It's in the interest of the entire planet."
Health officials in the UK this week announced the first six cases of the Brazilian variant, including one mystery passenger who did not fill in a test registration card. Officials said they were seeking passengers on Swissair flight LX318 from Sao Paulo, which arrived at Heathrow via Zurich on Feb 10.
At the weekend, Sao Paolo began an 11pm to 5am curfew after setting new records for hospitalisations.