KEY BISCAYNE, FLORIDA - SEPTEMBER 03: Enbal Sabag, a Nurse Practitioner, wears personal protection equipment as she administers a flu vaccination to Noel Janzen at the CVS pharmacy and MinuteClinic on September 03, 2020 in Key Biscayne, Florida. Flu shots are available at the nearly 10,000 CVS pharmacies and approximately 100 MinuteClinic locations across the country. Heath experts say getting the flu shot this year is important because the dangers of having COVID-19 and the flu simultaneously are still unknown.  (Photo by Joe Raedle/Getty Images)
This might be your most important flu vaccine ever
02:03 - Source: CNN
CNN  — 

Half a million US children have been diagnosed with Covid-19, according to the American Academy of Pediatrics and the Children’s Hospital Association.

The groups said 70,630 new child cases were reported from August 20 through September 3. This is a 16% increase in child cases over two weeks, bringing up the total to at least 513,415 cases, the groups said in their weekly report on pediatric coronavirus cases.

“These numbers are a chilling reminder of why we need to take this virus seriously,” American Academy of Pediatrics President Dr. Sally Goza said in a news release. “While much remains unknown about COVID-19, we do know that the spread among children reflects what is happening in the broader communities,” she added.

“A disproportionate number of cases are reported in Black and Hispanic children and in places where there is high poverty. We must work harder to address societal inequities that contribute to these disparities.”

Children represent nearly 10% of all reported cases in the US, according to the report. The child cases are likely underreported because the tally relies on state data that is inconsistently collected.

“This rapid rise in positive cases occurred over the summer, and as the weather cools, we know people will spend more time indoors,” Dr. Sean O’Leary, the vice chair of the AAP Committee on Infectious Diseases, said in a news release.

“Now we are heading into flu season. We must take this seriously and implement the public health measures we know can help,” O’Leary added.

“That includes wearing masks, avoiding large crowds, and maintaining social distance. In addition, it will be really important for everyone to get an influenza vaccine this year. These measures will help protect everyone, including children.”

The AAP recommends that any child 6 months or older get a flu shot – in line with recommendations from the US Centers for Disease Control and Prevention.

Pediatricians say it’s more important than ever to make sure kids get either the flu shot or the protective nasal spray before the end of October.

That’s because having two respiratory disease circulating at the same time – flu and coronavirus – will be confusing to doctors, parents and caregivers. Plus, hospitals and clinics could become overwhelmed with the double burden.

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The two viruses cause similar symptoms but a study published Tuesday in JAMA Network Open found that children hospitalized with Covid-19 were more likely to have fever, aches, diarrhea and vomiting than were children with influenza.

Children with Covid-19 also tended to be older and have at least one underlying health condition.

Covid-19 and seasonal flu in children lead to similar rates of hospitalization, intensive care admission, and need for a ventilator to help breathing, the study found. The CDC says 188 children died from flu over the 2019-2020 season.

CNN’s Jacqueline Howard contributed to this report