COVID-19 updates: LA has highest daily death total since April

Omicron became the dominant variant in New York City within five weeks after it was first detected, according to a new report released Thursday by the city's health department. 

By comparison, it took 20 weeks for the delta variant to become dominant.

The report, which details preliminary findings on the city's omicron wave, found that there have been lower hospitalization rates but more total hospitalizations compared to the delta wave due to "significantly greater case numbers."

Unvaccinated New Yorkers were more than eight times more likely to be hospitalized than those who were fully vaccinated early in the omicron wave, the report found. Black New Yorkers and people ages 75 and older also were more likely to be hospitalized.

Unvaccinated pregnant women with COVID-19 and their newborn babies have a higher risk of complications from the disease compared with those who are vaccinated, a new study found.

In the study, published Thursday in Nature Medicine, researchers from Public Health Scotland looked at vaccination rates and COVID-19 outcomes in 131,875 pregnant women in Scotland between Dec. 8, 2020, and Oct. 31, 2021, when the delta variant was dominant.

They found that 90.9% of COVID-19 hospital admissions, 98% of intensive care admissions and all 450 newborn deaths were in unvaccinated pregnant women. 

The study reiterates the importance of pregnant women getting vaccinated against the virus due to a greater risk of dangerous health complications from COVID-19. A growing body of research has shown the vaccines to be safe and effective for pregnant women.

-ABC News' Dr. Siobhan Deshauer, Sony Salzman and Dr. Alexis Carrington

Following heated exchanges between Dr. Anthony Fauci and several Republican senators at a Congressional hearing Tuesday, more than 200 prominent science and public health leaders have now penned an open letter voicing their support of the White House chief medical adviser's service and leadership -- and condemning attacks against him. 

"We deplore the personal attacks on Dr. Fauci," the letter says. "The criticism is inaccurate, unscientific, ill-founded in the facts and, increasingly, motivated by partisan politics. It is a distraction from what should be the national focus -- working together to finally overcome a pandemic that is killing about 500,000 people a year."

Signatories include former Senate majority leader Bill Frist, a Republican; Rich Besser, former acting director for the Centers for Disease Control and Prevention; members of President Joe Biden's transition COVID-19 task force; and several Nobel laureates.

The letter comes two days after a Health, Education, Labor and Pensions committee hearing, during which Fauci publicly accused Republican Sen. Rand Paul of fomenting the violent threats and harassment that he and his family have had to contend with during the pandemic's politicized climate.

-ABC News' Sasha Pezenik

More than 300 children with COVID-19 are in Ohio hospitals, including Dayton Children's Hospital, where workers are seeing a significant increase in pediatric COVID-19-related hospitalizations.

Dr. Vipul Patel, chief of pediatric intensive care at Dayton Children's, told ABC News the ICU is now busier than at any other point in the pandemic. 

COVID-19 is only exacerbating previously existing health issues for many children, Patel explained, adding that many parents are shocked to see their children become so sick, and some families have even expressed regret for not vaccinating their kids. Nationwide, about 35% of eligible children (ages 5 to 17) are fully vaccinated, according to federal data.

Dayton Children's respiratory therapist Hillary O’Neil said it's been particularly difficult to see children who are too young to understand what is happening sick and scared.

“You can see it in the faces of kids that can’t talk -- their eyes get really big and they, we watch them struggle to breathe,” O’Neil said. “Then on top of that we watch their parents struggle to watch their child, and that is sometimes just as hard as watching the kids.”

Jackie Kerby, whose baby, Enaeshya, is hospitalized with COVID-19, told ABC News, "She’s getting these fevers in the night, and they’re not coming down. … I am terribly scared."

Across the U.S. more than 5,000 children are currently hospitalized with a confirmed or suspected case of COVID-19, according to federal data. On average, hospital admissions among children have quadrupled over the last month.

-ABC News' Arielle Mitropoulos, Kayna Whitworth