(CNN) As school districts across the country reopen, some state officials are voicing concern about the vulnerability of children as the highly contagious coronavirus Delta variant takes aim at the unvaccinated.
Covid-19 cases are surging among children as the school year begins -- many in districts without mask mandates -- and the pandemic continues to force quarantines and other disruptions.
The latest weekly count of new pediatric cases -- 243,373 -- is about a 240% increase since July, the American Academy of Pediatrics said Monday.
The academy, in a joint report with the Children's Hospital Association, said severe cases among children are uncommon but more study is needed on the "longer-term impacts of the pandemic on children, including ways the virus may harm the long-term physical health of infected children."
So far, more than 5 million children have tested positive for Covid-19 since the start of the pandemic, representing 15.1% of all US cases.
Everyone 12 years and older is eligible for a Covid-19 vaccine but vaccination among children ages 12 to 17 is lower than in older groups, according to the US Centers for Disease Control and Prevention.
The US isn't alone. Covid-19 infections among children and adolescents in the Americas -- including the US and Canada -- have reached over 1.9 million, Dr. Carissa Etienne, director of the Pan American Health Organization, said on Wednesday.
There were more than 1.5 million Covid-19 cases among children and adolescents reported in the Americas all of last year.
In the US, some state officials are sounding the alarm:
In the last 60 days, about 60% of all Covid-19 in Georgia happened in K-12 schools -- about a sevenfold increase, state epidemiologist Dr. Cherie Drenzek said during a Department of Public Health board meeting Tuesday.
"The most significant epidemiologic trend that we have seen, that was much different than previous waves of this pandemic, is the tremendous impact that we have seen on school-aged children," she said.
That impact crosses all surveillance indicators, including new cases, hospitalizations and deaths, according to Drenzek.
Georgia is currently averaging nearly 7,000 new cases each day -- roughly a tenfold increase from July, according to data from Johns Hopkins University.
Georgia ranks near the bottom in the US in vaccination rates, with 43% fully vaccinated, according to the CDC.
Ohio Gov. Mike DeWine and the Ohio Children's Hospital Association this week urged school superintendents to require masks for staff and students.
"If we want our schools to stay open, the best way to do that is for those 12 and over to get vaccinated," he said during a virtual meeting with superintendents. "But because those under 12 are still too young to be vaccinated, we need students who come into school to wear a mask until we get through this."
Just over 54% of the state's public school students are under a mask requirement.
"Reasonable people may disagree about a lot, but we can all agree that we must keep our children in the classroom so they don't fall behind and so their parents can go to work and not take time off to watch their kids at home," DeWine said.
Since August 15, there have been 29,823 children -- ages 5 to 17 -- with confirmed or probable cases of Covid-19 in the state, according to a statement from the governor's office.
In the past week, Ohio saw a 44% increase in cases among school-aged children, compared to a 17% jump in the rest of the population.
The statement said school districts where masks are optional have seen a 54% week-over-week increase in cases, compared to a 34% spike in districts with mask requirements.
"This is a perfect storm, and it's impacting kids like it hasn't before," Nick Lashutka, president and CEO of the Ohio Children's Hospital Association said in the statement.
Pennsylvania has 10 times as many Covid-19 cases in school-aged children as it did at this time last year -- when the state was doing remote learning, according to Alison Beam, the acting health secretary.
Between September 4 and September 10 last year, there were 574 Covid-19 cases in children aged 5 to 18 in Pennsylvania, according to the Department of Health.
During the same time period in 2021, there were 5,371 cases in the same age group.
Vaccines for children between the ages of 5 and 11 could get the green light from the US Food and Drug Administration sometime this fall, Dr. Anthony Fauci said Tuesday.
"If you look at the studies that we at the (National Institutes of Health) are doing in collaboration with the pharmaceutical companies, there will be enough data to apply for an emergency use authorization both by Pfizer, a little bit later by Moderna," Fauci told CNN.
"I believe both of them -- with Pfizer first -- will very likely be able to have a situation where we'll be able to vaccinate children," he added. "If the FDA judges the data sufficient enough, we could do it by the fall."
School re-openings without proper masking have likely contributed to the increase in cases among children, according to Fauci.
"When you get a highly transmissible virus that's going around the community, you're going to see a lot more children get infected," he said.
But mask mandates in schools remain controversial.
In New York, two Long Island public school districts are suing the governor and state health commissioner over a statewide school mask mandate imposed ahead of the school year.
On Wednesday, data from Johns Hopkins University showed that 1 in 500 Americans has died from the coronavirus since the nation's first reported infection.