The United States reported a 23% drop in new cases of Covid-19 and a 16% fall in the number of people hospitalized with the virus for the week ended Feb. 14, with both figures declining for a fifth week in a row.

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.

The results are in from Johnson & Johnso’s global Phase III ENSEMBLE clinical trial, and the company’s single-shot vaccine is 66% effective overall in preventing moderate-to-severe Covid-19, 28 days after vaccination.

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.

The United States lost more than 23,000 lives to Covid-19 during the week ended Jan. 17, setting a record for the third week in a row, though the number of new infections and the amount of patients in hospitals both fell from the previous seven days.

The United States lost more than 22,000 lives to Covid-19 for the week ended Jan. 10, setting a record for the second week in a row, as new cases also hit a weekly high.

The United States recorded more than 15,000 deaths from Covid-19 and over 1.2 million new cases for the week ended Dec. 27, though those numbers may be artificially low due to reporting gaps over the Christmas holiday.

The United States lost 15,000 people to Covid-19 during the week ended Dec. 6, the deadliest seven days since April, and health officials warned that the worst is yet to come.

The United States recorded 10,000 coronavirus deaths and more than 1.1 million new cases for the week ended Nov. 29, although state and health officials said the Thanksgiving holiday likely caused numbers to be under-reported.

The United States recorded the country’s largest weekly rise in Covid-19 deaths since August, increasing 32% from the previous week to average about 1,500 people per day, according to a Reuters analysis of state and county reports.