Coronavirus cases were highest among older Americans at the start of the pandemic, but that changed this summer as health officials saw higher incidences of the virus among young adults.
A recent report from the Centers for Disease Control and Prevention found that adults aged 20-29 accounted for more than 20% of total COVID-19 cases between June and August, outpacing all other age groups in the U.S. The study, published in the agency’s Morbidity and Mortality Weekly Report on Wednesday, also suggests 20-somethings are a major driver of community spread of the virus.
“Given the role of asymptomatic and presymptomatic transmission, strict adherence to community mitigation strategies and personal preventive behaviors by younger adults is needed to help reduce the risk for infection and subsequent transmission of SARS-CoV-2 to persons at higher risk for severe illness,” study authors wrote.
Their review of the changing age distribution of COVID-19 found that overall, the median age of those infected with the virus has skewed younger in recent months.
In May, the median age for coronavirus cases was 46 and slid to 37 by July, the report shows. That number rose slightly to 38 in August.
The rate of new cases among U.S. adults in their 20s was particularly staggering. The monthly case count for those aged 20-29 saw a more than two-fold increase between May and July, data show. Folks in their 30s initially had the highest share of confirmed coronavirus cases in May (16.9%) but were quickly eclipsed by 20-somethings by June (20.2%).
This trend continued through the summer with people in their 20s accounting for 189,366 (or 21%) of total confirmed coronavirus cases in the U.S., according to the CDC report.
For the study, researchers relied on three indicators: total emergency room visits for COVID-19-like illness, positive SARS-CoV-2 RT-PCR test results and confirmed COVID-19 cases, as reported by state health facilities to the National Syndromic Surveillance Program.
Researchers found the downward age shift held true across all three indicators but varied by region.
In the Southeast for instance, the test positivity rate among 20-somethings “preceded increases among those aged ≥60 years by 4–15 days,” authors wrote. Similar trends were seen in the West and Northeast, where the median age for COVID-19 patients fell in June and rose in July before falling again in late August.
The findings provide “preliminary evidence that younger adults contributed to community transmission of COVID-19 to older adults,” researchers wrote. “Similar observations have been reported by the World Health Organization.”
So what’s causing the age shift? The CDC team had a few theories.
Young adults tend to work in “highly exposed” industries — including restaurants, bars and retail spaces — where they’re at increased risk of contracting COVID-19 and passing it along. Some 20-somethings also may not be the best at following social distancing rules and other precautions aimed at slowing the spread of the virus.
Coronavirus symptoms are often mild or nonexistent in younger adults, making it more likely that they’ll unknowingly pass it to those with health issues, according to the CDC.
“Emphasis should be placed on targeted mitigation strategies to reduce infection and transmission among younger adults, including age-appropriate prevention messages, restricting in-person gatherings and events, recommending mask use and social distancing ... and enforcing protection measures for essential and service industry workers,” researchers wrote.