RIO DE JANEIRO - Hospital admissions and deaths due to COVID-19 have declined in Brazil thanks to progress in vaccination against the virus, Brazil's Oswaldo Cruz Foundation (Fiocruz) said on Wednesday.

In its weekly bulletin on the pandemic, the federally-funded medical research facility said that for the first time since December, no Brazilian state has reported intensive care units (ICUs) with over 90 percent occupancy.

However, four states are in the "critical alert zone", with more than 80 percent ICU occupancy, including Santa Catarina (82 percent), Goias and Parana (at 81 percent occupancy each), and the Federal District (80 percent).

Most of Brazil is in the "medium alert zone", with ICU occupancy rates of 60 to 80 percent, while seven states are on low alert, with occupancy of less than 60 percent, including Acre, which has just 24 percent occupancy.

"Vaccines are especially effective in preventing serious cases," said Fiocruz, urging continued social distancing, use of masks and hygiene measures, and calling on the entire population to get vaccinated.

"The possibility of the emergence of variants with the potential to reduce the effectiveness of available vaccines is pertinent and cannot be overlooked," it added.

For the third week in a row, deaths caused by COVID-19 fell, although they remained at high levels, with more than 46,000 cases of infection and 1,300 deaths a day on average last week.

The fatality rate is around 3 percent, which is considered high.

Brazil has the world's second-highest pandemic death toll, with more than 535,000 deaths, and third-worst outbreak, with over 19 million cases.