ATLANTA - Seniors were near the front of the line for the COVID-19 vaccine last winter.
Knowing they were at higher risk of complications from the coronavirus, many of Americans 65 and older could not wait to roll up their sleeves.
As of Monday, 87% of US seniors have had one dose of the vaccine, and 77% are fully vaccinated, according to the CDC.
But, only about a third of younger adults 18 to 39 have been vaccinated, according to a new report from the CDC.
About 34% of adults 18 to 39 reported having received a COVID-19 vaccine, according to surveys conducted between March and the end of May.
That low rate troubles Dr. Felipe Lobelo, director of epidemiology for Kaiser Permanente in Georgia.
Dr. Lobelo is tracking the newer, more contagious Delta variant, now causing spikes in infections and hospitalizations in England, especially in younger adults.
"Almost all of them are in people that have not been vaccinated," Lobelo says.
The Delta variant, which makes up about 10% of sequenced cases in the US, could become the dominant strain in the US soon.
Health experts say it is about 60% more transmissible than the previously dominant Alpha strain of the virus, which was about 60% more contagious than the original virus that originated in Wuhan, China.
Dr. Lobelo says younger Americans and those who are unvaccinated are at risk of being infected by the Delta strain.
"As long as we have larger pockets of the population that are vulnerable, we are going to be at risk of seeing resurgences with this Delta variant," he says.
Those surveyed in the 18-to-24 age group were the least likely to have received the COVID-19 vaccine, and the most likely to say they felt unsure about getting vaccinated.
Researchers also found lower vaccination rates in individuals with lower incomes and education levels, non-Hispanic Black adults, people who were uninsured, and those living in rural areas.
Concerns about the safety and effectiveness of the vaccine were the top reasons cited for not being vaccinated or waiting on vaccination.
"Being a new vaccine, it's understandable that people are going to have questions, and misinformation could influence the way that they see vaccines or this particular vaccine," Dr. Lobelo says. "We have to educate, educate, educate."
While younger adults are less likely to have complications of COVID-19, Lobelo says, even those who have mild infections can develop lingering health problems, a condition known as long-COVID.
He says his wife, who was infected before she was eligible to be vaccinated, is still dealing with mild brain fog and fatigue months after her bout with the virus.
"We're seeing a lot of patients with these long, debilitating symptoms," Dr. Lobelo says. "You don't want to be risking your health long-term, because we don't understand what the long term impacts of having this virus are going to be. So, (there are) plenty of reasons to get vaccinated, obviously."
The CDC report found younger adults reported a higher level of trust in vaccine information coming from the CDC, their primary care providers and family and friends
They were less likely to trust vaccine information coming from their employers, faith leaders or social media, according to the report.
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