(CNN) — The US has now tallied more than 40 million Covid-19 cases across the pandemic, with more than 4 million of them reported in the last four weeks alone, according to data from Johns Hopkins University.
The count comes with a caveat: 40 million represents just officially reported positive test results, and many experts believe the actual number of infections is much larger.
Covid-19 cases have nevertheless generally been on the rise in much of the country since early summer. And the country’s seven-day average of new cases Monday (137,270 daily) was more than four times higher than Labor Day of last year (39,355 daily), according to Johns Hopkins data.
The jump in cases has translated into overcrowded hospitals and a rise in infections among children — of particular concern as many students return to their classrooms. And experts fear that a holiday weekend could make matters worse.
Last week, the US Centers for Disease Control and Prevention Director Dr. Rochelle Walensky advised unvaccinated Americans not to travel for the holiday and reminded vaccinated people that the high rate of virus transmission meant that it could be risky for them to travel as well.
The risk played out last year, when cases surged in 31 states and the positivity rate went up in 25 of them only two weeks after the Labor Day holiday.
One big difference between this year and last is the more transmissible Delta variant. Another is that Americans over 12 years old can get highly effective Covid-19 vaccines, which experts say is the best defense against the virus.
But only 53% of the total US population is fully vaccinated, and just 62% of eligible Americans are, leaving tens of millions very vulnerable.
“Here’s the important thing: Everyone that I’m hospitalizing is not vaccinated. We are, by and large across the country, not needing to hospitalize people that have gotten both doses of the vaccine,” Professor of Emergency Medicine and Associate Dean of Public Health and Brown University Dr. Megan Ranney said. “This is a disease of the unvaccinated right now.”
Alabama, Wyoming, Idaho, Mississippi and West Virginia all have less than 40% of their populations vaccinated, according to the CDC. Two of those states, Alabama and Mississippi, are also contending with their more than 90% ICU utilization.
Georgia, Arkansas, Texas and Florida join those states in less than 10% ICU capacity, according to data from the US Department of Health and Human Services.
“The takeaway for everyone is: get your shots and certainly wear a mask for that added layer of protection if you’re in public indoor spaces right now,” Ranney said.