A letter from the Emergency Nurses Association on behalf of its 52,000 members to President-elect Joe Biden, urged him to include nurses in his COVID-19 task force.

On Nov. 9, President-elect Biden and Vice President-elect Kamala Harris rolled out their transition COVID-19 advisory board.

"Dealing with the coronavirus pandemic is one of the most important battles our administration will face, and I will be informed by science and by experts," Biden said in a press release announcing the board.

"We were surprised that although the group contains ten medical doctors of varying specialties, there were no nurses -- and especially those nurses who are providing care on the front lines during this pandemic or have clinical expertise in infectious disease management -- named to the task force," the ENA's letter read.

"Nurses, including emergency nurses, have been on the frontlines of the pandemic since day one, performing critical triage, testing and bedside care functions for their patients," it continued. "Once a vaccine is approved, nurses will play a critical role in its administration to the public."

The ENA asked Biden to "expand the membership of your COVID-19 Task Force to include the unique perspective and clinical expertise of America’s nurses."

ABC News' Alexandra Svokos and Molly Nagle contributed to this report.

As coronavirus cases increase in New York City with a current 3.09% daily positivity rate and a 2.83% seven-day rolling average, Mayor Bill deBlasio said that parents should prepare for possible school closings.

"[The positive rate] is still below 3%, so schools remain open. But that number has gotten quite close to 3% and we are making preparations as a result in case that number does exceed 3% and we have to temporarily close our schools," the mayor told WNYC on Friday.

"People should get ready … this is not something any parent wants to deal with. We should get ready. And parents should have a plan for the rest of the month of November, that’s a safe way to think about it. Have an alternative plan for beginning as early as Monday for whatever will help them get through this month if school is not open," he said.

In New York City, there have been 916 new reported cases over a seven-day average and 121 hospitalizations.

ABC News' Aaron Katersky contributed to this report.

As he has repeatedly stressed throughout the pandemic, on Friday, the World Health Organization Director General Dr. Tedros Adhanom Ghebreyesus, once again urged countries to use all tools available to combat the virus, not just wait for a vaccine.

"There is no doubt that a vaccine will be a vital tool for controlling the pandemic, and we’re encouraged by the preliminary results of clinical trials released this week," Tedros said at the closing of the WHO's World Health Assembly.

"But we have a long way to go. The world cannot put all its eggs in one basket, and neglect the many other tools at our disposal that countries like Thailand have shown are effective for bringing this virus under control," he said. "The virus itself has not changed significantly, and nor have the measures needed to stop it. We know what works. First, know your epidemic and do the basics well. Find, isolate, test and care for cases. Trace and quarantine their contacts. And second, engage and empower communities to protect themselves and others with the full range of measures: physical distance, avoiding crowds, ventilation, hand hygiene, and masks," he said.

ABC News' Kirit M. Radia contributed to this report.

For the first time since the pandemic, official travel advisories have been issued for the West Coast.