The United States administered Covid-19 vaccinations to around 600,000 children ages 12 to 15 last week after regulators cleared Pfizer’s and BioNTech’s shots for use in that age group, U.S. Centers for Disease Control and Prevention Director Rochelle Walensky said in a media call on May 18.

New cases of Covid-19 in the United States fell for a third week in a row, dropping 15 percent during the week ended May 2 to 347,000 – the lowest weekly total since October – according to a Reuters analysis of state and county data.

The European Medicines Agency (EMA) said on April 7 it had found a possible link between AstraZeneca’s coronavirus vaccine and reports of very rare cases of blood clots in people who had received the shot.

Coronavirus-related deaths worldwide crossed 3 million on April 6, according to a Reuters tally, as the latest global resurgence of Covid-19 infections is challenging vaccination efforts across the globe.

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.