People under 45 driving up cases
55% of new infections among young age group
Before Memorial Day, the majority of coronavirus cases were found in people 45 and older.
Now, the opposite is true. People under 45 made up 42% of cases before Memorial Day weekend but 55% of new cases since then, a USA TODAY analysis of data from the Centers for Disease Control and Prevention found.
The trend holds in places where new cases are surging and in those that are not, according to records from 25 states with published age data available from late May.
The rapid growth in coronavirus infections among younger Americans is one factor behind why some states have broken single-day records this week.
New cases among people younger than 45 have grown nearly twice as fast as for people 65 and older since late May. Had all age groups experienced the same growth rate as seniors, the country would have added 30% fewer new cases over the past month.
Experts say the shift toward younger patients in part reflects a change in testing practices. States that have ramped up their testing capacity are better able to identify people with less severe symptoms, who tend to be younger. Contact tracing is also turning up more children of infected adults, experts say.
Early on in the pandemic, limited testing resources focused on people with the worst symptoms. Large outbreaks among vulnerable populations, such as nursing homes, further concentrated tests among older Americans.
But in most states, disease trackers say the data shows it’s not just a matter of increased testing. Children, young adults and middle-aged people are being infected more often than before Memorial Day.
One possible reason: They have moved out of lockdown mode more rapidly than seniors as businesses reopen.
Tyler Workman recently traveled from Seattle to visit a friend and her friend’s sister in Phoenix, where the group went out together a lot, shopping at Nordstrom and eating at restaurants. Just as the trip ended, Workman learned that her friend’s sister had developed COVID-19.
“For me, in Seattle, you don’t even see people walking on the street without their masks on. If they see you on the same sidewalk, they’ll cross the street,” she said. “Being in Arizona, younger people weren’t taking the precautions they should be. Pretty much all the bars were packed.”
Multiple infection opportunities
Some experts speculate that while older Americans have continued to be cautious about exposure and diligent about precautions like wearing masks, younger age groups have been more likely to return to working and to gathering in person without social distancing.
“We have clearly not reached that population well,” said Dr. Julie Vaishampayan, public health officer for Stanislaus County in California and chairperson of the public health committee of the Infectious Diseases Society of
America.
Unlike earlier clusters, which often were linked to particular events or workplaces, Vaishampayan said, an increasing number of cases in her county can’t be tied to a particular place. People – most of them younger – are simply doing more in the community and often without wearing masks or staying 6 feet apart, so there are multiple opportunities to become infected and to infect others.
Workman can’t understand why some places in the country are acting so much differently than others.
“Seattle and L.A. are both pretty hardcore quarantined and Pheonix is really not,” she said. “It was eye-opening how different they really are.”
In 18 states with recent increases in new cases, a USA TODAY analysis found that people under 50 comprised 56% to 73% of new infections since late May. Before that, this younger age group accounted for 42% to 65% of all cases.
In Arizona, people under 19 accounted for more new cases since Memorial Day than those 65 and older.
“The fact we’re seeing rising numbers along with a higher proportion of tests in some states suggests that, in certain places, it is most likely that there are more infections happening in young people, either through workplace interactions or things opening back up,” said Natalie Dean, a biostatistician specializing in infectious disease epidemiology at the University of Florida.
In Michigan – which was an early hot spot this spring – the number of cases for people younger than 20 increased faster than older age groups between May 22 and June 22.
“That gap between being contained and being completely uncontrolled is narrow,” said Dr. Preeti Malani, chief health officer for the University of Michigan and a professor of infectious diseases. “It could be a matter of one event or one large gathering. That could be the difference between an entire community being at risk and the spread being contained.”
Deaths and hospitalizations
Nationally, increasing case numbers hasn’t yet led to an equally large spike in hospitalizations and deaths.
That could be because more cases are among people with less risk for severe symptoms. It might also be because there is a delay between when people test positive and when their cases become acute.
“They may be there weeks or even months before they die,” said Malani. “Even if they survive, they’re left with a lot of debilitating conditions. … A lot of younger people are not hospitalized, but they’re also not working. They’re at home and have prolonged recoveries.”
Hospitalization rates for all age groups are declining, but people under 50 are a growing share of COVID-19 patients filling beds, according to CDC data from hospitals in 14 states.
Infectious disease experts also cautioned it’s only a matter of time before new outbreaks – even among people who are younger – lead to more deaths among Americans of all ages.
“Inevitably, infection will spread,” said Stephen Kissler, of the Harvard T.H. Chan School of Public Health. “So I think that just because infection is currently mostly spreading in young people is not really a reason to breathe a sigh of relief.”