The U.S. was administering an average of 3.1 million Covid-19 shots a day over the past seven days and hit a new record over the weekend of more than 4 million shots in a single day as vaccine manufacturing picks up pace and more mass vaccination sites open, Andy Slavitt, White House senior advisor on Covid-19, told reporters on Monday.

“To date, nearly one in three Americans and over 40% of adults have had at least one shot, and nearly one in four adults is now fully vaccinated,” Slavitt said.

He added that 75% of seniors have now received at least one shot and more than half are fully vaccinated.

Despite the progress, Slavitt urged Americans to remain vigilant to prevent the virus from spreading by wearing masks, practicing social distancing, and getting a vaccine when available.

“So we are on the right track,” he said, “but as you heard from the President, we are not there yet. The worst thing we can do now is to confuse progress with victory.”

The daily coronavirus death toll in the US is at its lowest level in months as the country speeds up vaccine delivery. At the same time, outbreaks in states like Michigan are fueling fears of another nationwide surge in Covid-19.

US vaccine shots administered

The Centers for Disease Control and Prevention reported a daily record of 4.1 million vaccinations given on Saturday, and more than 3 million vaccination shots were given in each of the past four days.

The 7-day average of recordings made in the US is now just over 3 million per day.

US percentage of the vaccinated population

According to CDC data, more than 165 million doses of the Pfizer-BioNTech, Moderna and Johnson & Johnson Covid-19 vaccines have been administered in the US.

Almost a third of the population has received at least one dose, and 18.5% of Americans are fully vaccinated.

Of those 65 year olds and older, 75% received at least one dose and 55% are fully vaccinated, according to the CDC.

US Covid cases

About 63,280 new coronavirus cases are reported in the United States every day, according to a 7-day average of data collected by Johns Hopkins University. The number of cases has been picking up again recently after falling sharply for months in January highs.

The growth of new cases is showing signs of plateauing after a small number of new cases reported for Sunday, but many states haven’t reported data because of Easter. It will likely take a few days for the holiday weekend case to be reported and death numbers reported and collected. From this point on, the recent direction of the outbreak becomes clearer.

Michigan, where the average daily new cases are up 39% from a week ago, has the worst per capita outbreak in the country. The state’s seven-day average of nearly 6,500 new cases per day is approaching the level of the winter surge, when the number of cases there peaked averaging 8,300 per day.

Dr. Scott Gottlieb, a former commissioner for the Food and Drug Administration, told CNBC’s “Squawk Box” Monday that the recent surge in Michigan and other states such as Minnesota and Massachusetts had multiple causes. The spread of virus variants, colder climates making it harder to congregate outdoors, the reopening of schools and increased mobility among residents all contribute to the spread, Gottlieb said.

He does not expect these factors to lead to a nationwide spike in new cases.

“I don’t think this will be the beginning of a real fourth wave,” said Gottlieb. “I think these will be regionalized outbreaks, and hopefully we’ll get beyond that as we vaccinate more.”

US Covid deaths

The daily US Covid death toll is 797 based on a weekly average from Hopkins data. While that number is still up, it is at its lowest level since late October.

Disclosure: Scott Gottlieb is a CNBC employee and a member of the boards of directors of Pfizer, genetic testing startup Tempus, health technology company Aetion Inc., and biotech company Illumina. He is also co-chair of the Healthy Sail Panel for Norwegian Cruise Line Holdings and Royal Caribbean.