The United States is preparing for the possibility that a booster shot will be needed between nine to 12 months after people are initially vaccinated against Covid-19, a White House official said on April 15.

Brazil’s richest and most populous state, Sao Paulo, warned its ability to care for seriously ill Covid-19 patients was on the verge of collapse as it ran perilously low on key drugs, according to a letter to the federal government seen by the Folha de Sao Paulo newspaper.

U.S. federal health agencies on April 13 recommended pausing the use of Johnson & Johnson’s Covid-19 vaccine after six women under 50 given the shot developed rare blood clots, dealing a fresh setback to efforts to tackle the pandemic.

India reported another record number of new Covid-19 infections on April 9 and daily deaths hit their highest in more than five months, as the country battles a second wave of infections and states complain of a persistent vaccine shortage.

Brazil on April 8 set a daily record of 4,249 Covid-19 deaths, with overwhelmed hospitals running low on supplies and the Senate about to open an investigation into the response of the government of President Jair Bolsonaro, who has played down the pandemic from the start.

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.

President Joe Biden will announce on April 6 that the U.S. delivered 150 million vaccines since he took office and move up by nearly two weeks a deadline to make doses widely available, according to a person familiar with the matter.

Covid-19 was the primary or contributing cause of 377,883 deaths in the United States during 2021, with a particularly high toll among the elderly, according to a government report released on March 31.

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 22 percent decline in deaths from Covid-19 during the week ended March 14, while vaccinations accelerated to a record 2.4 million shots per day, according to a Reuters analysis of state, county and CDC data.