Costa Mesa, California (CNN)Kennedy Stonum, a high school junior, deflected repeated entreaties from her father to please get vaccinated against Covid-19.
"I would send her articles. I would send her studies. I would send her whatever I thought might either scare her enough about Covid to get the vaccine or allay her concerns enough about the vaccine," said Lee Stonum, 41, a public defender in Orange County, California. His mother, who lives in Cleveland, also sent emails to her granddaughter urging her to get the shots.
"She was very skilled at blowing it off," Stonum said of his only child. "It was constantly, 'OK, I'll think about it.' It was never an outright 'no.' "
Tyler Gilreath, 20, resisted the constant nagging and cajoling of his mother, Tamra Demello, to get the Covid-19 vaccine.
"He was one of those kids who had to make every mistake himself, because he always knew best," said Demello, 60, of Apex, North Carolina. "The more a mother's lips move, the less the ears on their male children open."
Both young people recently died of Covid-19 -- Kennedy Stonum on February 11, Gilreath in September. The vaccines had been available to them for months before their deaths.
Parents of teenagers and young adults are familiar with this tug of war: Their kids, soon to be full-fledged adults, resist parental input and think they know what is right. They learn about Covid-19 from friends and posts on social media platforms, such as Instagram and TikTok -- not always the most accurate sources.
Parents may have enough leverage to compel their children to get vaccinated.
"Take their cell phone away. It would be three hours before they were lining up at the clinic," Stonum said.
A feeling of youthful invincibility
Covid-19 deaths among young people are uncommon, but Kennedy Stonum and Gilreath are certainly not alone: For example, an unvaccinated 15-year-old girl from Pensacola, Florida, died in September, as did an unvaccinated 16-year-old high school football player from Mississippi.
Vaccination rates remain low among young people: Just over 57% of kids ages 12 to 17 and 62% of 18- to 24-year-olds are fully vaccinated, compared with 69% of the entire vaccine-eligible population of the United States.
That is in part due to a feeling of youthful invincibility, amplified because the disease is far less deadly among young people than older Americans.
Children and adolescents account for 22% of the US population but an estimated 3% of hospitalizations related to Covid-19 and less than 0.1% of Covid-19 deaths. Of the nearly 1 million people in the United States who have died of Covid-19, the vast majority have been 65 and older.
Teen vaccine resistance is also hardened by a stream of social media posts, confusing and shifting recommendations from public health officials, and a youthful skepticism of authority, experts say.
Kennedy Stonum "spent a lot of time on TikTok and on social media, and I think she was picking up some misinformation there," said Lee Stonum, sitting on the back patio of his home on a warm, brilliantly sunny day in late February.
She was also hearing from her peers that the vaccines could cause sterility, Stonum said. "Her biggest stated reason for not wanting to do it was that we didn't know what the long-term impact on fertility was," he said.
Gilreath was wary of the new vaccines, particularly the potential impact on his heart, Demello said. "He did a lot of research -- a lot of times more than I did," she said. But he also listened to "a lot of the conspiracy stuff," she said, and he had that youthful sense of immortality, telling her: ' 'If I get sick, I'll only get sick for a couple of days, and I'll get over it. I'm healthy.' "
Rupali Limaye, deputy director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health, understands the dynamic. "We've created a bit of a perfect storm in which individuals are thinking, 'I don't believe the doctor; I don't believe the government; I'm going to listen to my friends.' And that has really allowed conspiracy theories and other misinformation to flourish," she said.
Many adolescents and 20-somethings also don't believe Covid-19 can hurt them because they think " 'I'm young, I'm healthy, and I don't see why I need to be concerned about this,' " Limaye said.
'There's a percentage of kids who get very sick'
But young people who remain unvaccinated court danger. Data from December shows that unvaccinated kids ages 12 to 17 were six times as likely to be hospitalized with Covid-19 as their vaccinated peers.
"Most kids get mild illness, but there's a percentage of kids who get very sick," said Colleen Kraft, a pediatrician at the Children's Hospital Los Angeles. "Two to six weeks out, kids can develop this multisystem inflammatory condition, where they can get inflammation around their heart and liver and other organs, and they can die from that."
Kraft also pointed to the risk of diabetes after a coronavirus infection and of myocarditis, an inflammation of the heart muscle. Research shows the rate of myocarditis or cardiac injury in people who have had Covid-19 is 100 times as high as the rate of myocarditis that has been linked to the Pfizer and Moderna vaccines.