New cases of Covid-19 in the United States rose 5 percent to more than 450,000 during the week ended April 4, the third week in a row that infections increased, according to a Reuters analysis of state and county data.

New cases of Covid-19 in the United States rose 9 percent to more than 431,000 for the week ended March 28, the first time since January that cases increased for two weeks in a row, according to a Reuters analysis of state and county data.

The United States reported a 12 percent decline in new cases of Covid-19 for the week ended March 7, while vaccinations accelerated to a record 2.2 million shots per day, according to a Reuters analysis of state, county and CDC data.

The United States must stick to a two-dose strategy for the Pfizer-BioNTech and Moderna Covid-19 vaccines, top U.S. infectious disease official Anthony Fauci told the Washington Post newspaper.

The United States reported a 3 percent decline in new cases of Covid-19 for the week ended Feb. 28, a much smaller drop than in the previous six weeks, and health officials warned that progress against the global pandemic was stalling.

Pfizer Inc. and BioNTech SE started an international study with 4,000 volunteers to evaluate the safety and effectiveness of their COVID-19 vaccine in healthy pregnant women.

People who have received the full course of Covid-19 vaccines can skip the standard 14-day quarantine after exposure to someone with the infection as long as they remain asymptomatic, U.S. public health officials advised.

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.

U.S. public health officials said a second Covid-19 shot could be administered as much as six weeks apart from the first one in situations where it was not possible to get a booster dose immediately.

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.