COVID-19 updates: Austria orders nationwide lockdown for unvaccinated residents

The U.S. saw 107,000 pediatric cases last week, an uptick following eight consecutive weeks of declines, according to a weekly report from the American Academy of Pediatrics and the Children’s Hospital Association.

But this is still much lower than the pandemic peak -- 252,000 child cases within one week – which was recorded in early September.

Last week, children accounted for 24% of the cases. Children make up 22.2% of the U.S. population.

Approximately 45.8% of adolescents ages 12 to 17 have been fully vaccinated.

Severe illness due to COVID-19 remains "uncommon" among children, the two organizations wrote in the report. However, AAP and CHA continue to warn that there is an urgent need to collect more data on the long-term consequences of the pandemic on children, "including ways the virus may harm the long-term physical health of infected children, as well as its emotional and mental health effects."

-ABC News' Arielle Mitropoulos

Los Angeles' new vaccine mandate goes into effect Monday, requiring proof of vaccination to enter most public indoor spaces, including: any establishments where food or beverages are served; gyms and fitness venues; entertainment and recreation venues; personal care establishments; and buildings owned or operated by the city.

The mandate also requires proof of vaccination for large outdoor events with 5,000 or more attendees.

Enforcement will begin on Nov. 29.

-ABC News' Catherine Thorbecke

Regeneron's monoclonal antibody treatment can lower the risk of contracting COVID-19 by nearly 82% for up to eight months, the company said.

Regeneron's monoclonal antibody treatment, given as an intravenous infusion or a subcutaneous injection, is already FDA-authorized as a way to prevent COVID-19 among people who have recently been exposed and are considered "high risk" for more serious illness. This new data shows that when given as preventative measure, it dramatically reduces the risk of infection for up to eight months. 

Regeneron and the FDA say that vaccination is the best way to prevent infection and serious illness. However, Regeneron's antibody treatment can be a good option for people who are immune compromised or haven't mounted an adequate immune response through the vaccine.

-ABC News' Sony Salzman, Sasha Pezenik

The U.S. reopened borders to vaccinated travelers on Monday after 20 months of being closed to many countries, including the United Kingdom, Brazil, China, India, South Africa and most of Europe.

In January, as the vaccine was distributed on both sides of the Atlantic, the ban was kept in place, with the Biden administration stating concerns about the delta variant.

On Oct. 20, the Biden administration announced it was lifting the ban on vaccinated travelers.

The ban, which only applies to vaccinated travelers, still excludes many countries where the vaccine is not yet easily available or recognized by the U.S.

-ABC News' Zoe Chevalier