Brazil's death toll from Covid-19 surpassed 500,000 on Saturday as experts warn that the world's second-deadliest outbreak may worsen due to delayed vaccinations and the government's refusal to back social distancing measures.

Only 11% of Brazilians have been fully vaccinated and epidemiologists warn that, with winter arriving in the southern hemisphere and new variants of the coronavirus circulating, deaths will continue to mount even if immunizations gain steam.

Thousands took to the streets across Brazil on Saturday to protest against President Jair Bolsonaro's pandemic response, blasting the leader for not acquiring vaccines fast enough and for questioning the need for mask-wearing.