The United States reported a 25% drop in new cases of Covid-19 to about 825,000 during the week ended Feb. 7, the biggest fall since the pandemic started, although health officials said they were worried new variants of the virus could slow or reverse this progress.

Mexico surpassed India in confirmed Covid-19 deaths on Jan. 29, giving the Latin American country the third-highest toll worldwide, according to a Reuters tally of official data.

The United States reported a 21% drop in new cases of Covid-19 for the week ended Jan. 24, as all but one state reported declines in new infections, and the number of coronavirus patients in hospitals also fell.

China on Jan. 23 reported a slight increase in new cases of Covid-19 as the country marked the anniversary of the world’s first coronavirus lockdown, in the city of Wuhan where the disease emerged in late 2019.

Joe Biden is resetting the United States’ response to the Covid-19 crisis after being sworn in as president to lead a country reeling from the nation’s worst public health crisis in more than a century.

The U.S. coronavirus death toll topped 400,000 on Jan. 19, according to a Reuters tally, as the country hardest hit by the pandemic struggled to meet the demand for vaccines to stem the spread of infection.

Global deaths from Covid-19 are expected to top 100,000 per week “very soon,” the World Health Organization’s top emergency expert Mike Ryan said.

U.S. President-elect Joe Biden said he would order increased production of syringes and other supplies to ramp up vaccinations against Covid-19 and improve upon the Trump administration rollout that he called a “dismal failure.”

The worldwide coronavirus death toll surpassed 2 million on Jan. 15, according to a Reuters tally, as nations around the world are trying to procure multiple vaccines and detect new Covid-19 variants.

More than 10 million Americans had received their first dose of a Covid-19 vaccine as of Jan. 13, according to the U.S. Centers for Disease Control and Prevention, as the year-old pandemic roared on unchecked.