CNN  — 

As students and staff return to school, the highly transmissible Delta variant of Covid-19 has caused cases, hospitalizations and death rates to soar across the country. Children under 12 are particularly vulnerable to infection as they are not yet eligible for vaccination, including the FDA-approved Pfizer vaccine.

Contrary to research early in the pandemic, children are just as likely to become infected as adults. According to the CDC, Covid-19 infection rates for adolescents aged 5 to 17 were as high as in adults 18 to 49, and higher than rates in adults over 50.

There have been 4.8 million cases of Covid-19 in children since April 2020, according to the American Association of Pediatrics, making up about 15% of all documented cases in the United States. In the last month, the number of new weekly cases has surged to near-peak levels.

Areas across the country with lower than average vaccination rates are experiencing higher increases in Covid-19 cases among children. In Mississippi, where only 37.7% of residents are fully vaccinated, there has been a 29% increase in cumulative Covid-19 cases in children over the past two weeks.

Total hospitalizations are also climbing to rates not seen since before vaccines were readily available. Average hospitalizations for children with Covid jumped in early 2021 and have remained high.

This is to be expected, said Dr. Sean O’Leary, vice chair of the American Association of Pediatrics Committee on Infectious Diseases. “This is a reflection of both the infectiousness of the Delta variants and what happens to unvaccinated populations as infections continue,” he told CNN.

As the pandemic continues, and vaccine eligibility remains on hold, children are increasingly experiencing the ramifications. Available data shows that child hospitalizations as a share of all hospitalizations are on the rise.

This can be attributed in part to vaccine availability in people 12 and older, but in cities like San Francisco, where vaccination rates are 19.6% points higher than the national average of 52.4%, children admitted to hospitals fit a consistent profile.

“We are finding that our older pediatric patients have not been vaccinated. In the case of younger pediatric patients, their parents have not been vaccinated,” said Suzanne Leigh, a representative at UCSF Benioff’s Children Hospital.

As total hospitalizations have surged across the country, health care facilities are overburdened and facing familiar shortages.

Many pediatric units are at capacity as they see an influx of child Covid patients on top of an unseasonable epidemic of respiratory syncytial virus (RSV).

Hospitals often plan for extra staffing during the winter flu season, but a late-summer onslaught of Covid-19 cases has caused unexpected health care staff shortages in many areas of the country. “[Hospitals] have all kinds of plans to make sure they’re properly staffed. And so when there’s a curveball, like an RSV season in the summer, that by itself creates a problem,” said Dr. O’Leary.

Dr. Sarah Combs, an emergency physician at Children’s National Hospital in Washington, D.C., is optimistic about the effectiveness of safety measures: “I think it’s understandable that there’s anxiety, but in some respects I think we should embrace the anxiety,” she said. “It’s very easy to get fatigued and get sick and tired of doing the same old, same old [precautions], but that’s when we let our guard down… We are going back to school with eyes wide open.”

As students return to school, proven mitigation measures are needed to protect children who remain vulnerable to the pandemic and are shouldering the impact of decisions out of their control.