Coronavirus vaccine
Coronavirus vaccineNasser Ishtayeh/Flash90

The United States is currently at the lowest rate of COVID-19 cases it has seen since March 2020, an NBC News analysis showed. The site added that medical authorities expect it to stay at that level well into the summer.

Cases spiked after a wave of the virus hit New York City last year, peaking in April and eventually settling into a rough average of 19,000 cases a week; on Wednesday, the average went to 16860, the lowest average since March 29, 2020.

Overconfident governors lifted restrictions too early last June, believing the worst of the virus to be behind them; they were rapidly proved wrong as cases surged past 300,000 a week. As the country attempts to reopen once again this June, though, experts have opined that another such surge is unlikely; there have been some drastic changes in the situation since last year, including the beginning of an aggressive and wide-ranging vaccination campaign.

“The level of vaccination in this country has taken any major national surge off the table,” Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, told NBC News.

Bill Hanage, an associate professor of epidemiology at the Harvard T.H. Chan School of Public Health, told the site: “We expect the summer to be relatively quiet from the combination of the high rates of vaccination, a certain amount of immunity from infection, and seasonality.”

Hanage added that fewer cases may have been reported due to Memorial Day weekend, but that as those cases are reported, there may be an increase. Despite this, he expressed hope that the overall trend will continue downwards.

Both Osterholm and Hanage told NBC News that in areas with lower vaccination rates, more localized outbreaks are likely to occur.

Some states have been slower to vaccinate their populations; Texas, for instance, remains vulnerable to outbreaks. Scientists also caution that a large enough population remains vulnerable even at relatively high percentages of vaccination.

“Even if 90 percent of the people in the community are vaccinated, if the 10 percent who are not all hang out together, and the virus is introduced to them, a large proportion of them could become infected,” Hanage told NBC.

Winter weather will be the biggest test, with large numbers of people clustered indoors for extended periods of time in artificially heated conditions, ideal for transmission, the site noted, adding that thanks to the vaccines, a winter spike will likely still be lower than last year's.