Washington, Sep 2 (IANS): As the US is surpassing an average of 160,000 new Covid-19 cases a day, the spread of the more transmissible Delta variant and the return of many students to the classroom for a new academic year seriously concern officials and health experts.

The pandemic is not only stretching hospitals thin with the surge of patients, particularly unvaccinated people and children, but also wearing the country out in the fields of tourism, tech businesses and social welfare, Xinhua news agency reported on Thursday.

More US kids were hospitalised with Covid-19 in August than any other time this past year -- proving how seriously the Delta variant can hit any age group, according to the Centers for Disease Control and Prevention (CDC).

Between August 20 and 26, an average of 330 children were admitted to hospitals every day with Covid, it said.

That's the highest rate of new Covid hospitalisations among children in more than a year -- a record that was broken several times in August, according to CDC data.

CNN on Tuesday quoted doctors as saying that it's crucial to protect children against the Delta variant, not just for the sake of their health and to keep in-person learning, but also to help prevent more aggressive variants from setting the entire country back.

At a Tuesday afternoon news conference, Pennsylvania Governor Tom Wolf announced an order going into effect statewide on September 7, under which masks must be worn inside buildings of K-12 schools, child care providers, and early learning programs.

In contrast with Pennsylvania, Arizona ignored federal recommendations and banned school mask mandates weeks before classes resumed.

Now, as the state's students are back in school, coronavirus infections are forcing thousands of children and teachers into quarantine.

"Now the back-to-school turmoil has cascaded far beyond Arizona's classrooms, igniting a political uproar for Governor Doug Ducey and other Republican leaders in this fast-changing desert battleground. The tumult underscores the perilous decisions facing governors in swing states where voters are divided over Covid-19 safety measures and personal freedoms," The New York Times reported on Wednesday.

Education groups have sued to overturn the mask-mandate ban, and more than a dozen school districts across Arizona have passed mask mandates despite the ban.

The administration of President Joe Biden warned governors like Ducey and Ron DeSantis of Florida not to block federal money from pro-masking schools, according to the report.

Due to the surge of COVID-19 cases, CDC Director Rochelle Walensky said that unvaccinated Americans should not travel during the Labor Day holiday weekend.

"First and foremost, if you are unvaccinated, we would recommend not traveling," said the director, adding that while people who are fully vaccinated can travel with precautions, current transmission rates mean they, too, need to take Covid-19 risk into consideration when deciding whether to travel.

Health experts have said that vaccination is the best way to protect against the virus' spread, and of those eligible for vaccinations, which includes Americans 12-years-old and older, 38.5 per cent are not fully vaccinated yet, according to data from the CDC.

This week, data presented by a CDC vaccine adviser showed a hospitalisation rate 16 times greater in the unvaccinated population than in those vaccinated.

Partly due to the coronavirus pandemic, the Social Security trust funds most Americans rely on for their retirement will run out of money in 12 years, one year sooner than expected, according to an annual government report.

Two Social Security funds are overseen by the Treasury Department: the Old-Age and Survivors Insurance Trust Fund and the Disability Insurance Trust Fund.

"The finances of both programs have been significantly affected by the pandemic and the recession of 2020," the Treasury Department said on Tuesday.

The combined effects of a dive in employment, interest rates, earnings and GDP, as well as higher mortality for the next few years "all significantly impact the outlook of the programs".

As of Thursday morning, the US continues to be the worst-hit country with the world's highest number of cases and deaths at 39,388,909 and 642,004, respectively.