Nearly 200,000 children in the United States tested positive for COVID-19 last month including 61,000 new cases reported in the one-week period ending Oct. 29, according to state health department data compiled by the American Academy of Pediatrics and the Children’s Hospital Association.

That one-week stretch marks the greatest single weekly increase in new cases among children seen thus far in the U.S. outbreak. 

"This is a stark reminder of the impact this pandemic is having on everyone – including our children and adolescents," Dr. Sally Goza, president of AAP, said in a statement. "This virus is highly contagious, and as we see spikes in many communities, children are more likely to be infected, too."

In total, more than 853,000 kids have tested positive for COVID-19, a number AAP believes to be low, given that children often experience mild COVID symptoms and aren’t tested as frequently as adults.

Gov. Charlie Baker rolled out a series of executive orders in Massachusetts Monday as COVID-19 cases in the state continue to rise. 

According to the governor's office, residents are to be at home between 10 p.m. and 5 a.m., although going to work, essential trips for food and medicine and exercising outdoors are still permitted. In-person dining in restaurants will end at 9:30 p.m.

Indoor gatherings at private residences are limited to 10 people; 25 for outdoor events. Anyone found not to be in compliance with the new rules can be fined up to $500 for each person above the limit. 

The new orders, which take effect on Nov. 6, come after Massachusetts reported more than 1,000 COVID-19 cases for nine consecutive days.

ABC News’ Arielle Mitropoulos contributed to this report.

The world can learn from countries that have successfully reduced the number of COVID-19 cases, WHO Director General Dr. Tedros Adhanom Ghebreyesus said during a remote press conference Monday. 

Tedros, who is currently quarantining after being exposed to someone with COVID-19, invited professor Yae-jean Kim, an infectious disease expert from Seoul's Samsung Medical Center in South Korea, to explain how the country brought its outbreak under control. According to Kim, the key elements of South Korea’s response were rapid PCR testing and isolation; transparent communication with the public through press releases and conferences; and public participation and compliance with public health measures.

ABC News’ Christine Theodorou contributed to this report.

Dr. Anthony Fauci said Monday he didn’t anticipate how much of a problem pandemic fatigue would be for Americans. 

"I think one of the things that I tried to emphasize as often as I possibly can, is that this will end," Fauci told a panel of doctors from Harvard University. "Because so many adults are vulnerable to the virus, the concept of reaching herd immunity by letting people live their lives normally isn’t the way forward. Instead, a combination of a vaccine and public health measures, as well as optimism about the future, is key."

He went on, "We really do have to be positive. I believe the idea that a vaccine is on the horizon is going to be playing a major, major role in how people accept the continuation of the stringent public health restrictions that they have if they don't see any relief in sight."

ABC News' Stephanie Ebbs contributed to this report.