An outbreak of COVID-19, resulting in 77 positive cases, has been traced to a youth basketball tournament held last month in California's Santa Clara County, public health officials said Friday.

At the tournament, held Nov. 7 and 8 at Courtside Basketball Center in Placer County, were 39 middle school and high school players, three coaches and 35 “additional contacts.”

Officials said it violated local and state orders for youth sports put in place during the coronavirus pandemic.

Another 17 cases outside the county have also been traced to the event, officials said in a news release.

“This outbreak is a troubling reminder that the widespread prevalence of COVID-19 in our community threatens all of us, and does not limit itself to geographic boundaries,” Dr. Monika Roy, Santa Clara County’s assistant public health officer, said in a statement.

“Public Health orders, directives, and guidance around contact sports and sporting events are in place for a reason. The risk of transmission in these settings can easily result in community spread that threatens the most vulnerable among us.”

The California Department of Public Health is investigating the incident, according to the news release, and Courtside’s website said the center is closed until further notice “out of precaution with the statewide lockdown and for the safety of all.”

The outbreak comes as California is seeing record numbers of COVID-19 cases during the holiday season.

FedEx took to Twitter Friday night to announce that it's on track to start delivering Pfizer's COVID-19 vaccine, which was given emergency use authorization by the Food and Drug Administration Friday.

“We’re in motion to begin delivering our first shipment of COVID-19 vaccines from @pfizer -@BioNTech_Group to communities across the U.S.,"FedEx tweeted.

In a press release, the transportation company -- which has more than 90 cold chain facilities across five continents -- said it will use its FedEx Priority Overnight service to get vaccines to dosing centers around the country, and soon, the world.

"Vaccine distribution will be balanced among major cargo carriers, and FedEx is working closely with healthcare customers to prepare for additional vaccine shipments and transportation of critical vaccine-related supplies," they said in their statement.

Mexico approved emergency use of Pfizer and BioNTech's COVID-19 vaccine on Friday.

The announcement came shortly before the U.S. Food and Drug Administration said that it had authorized Pfizer's vaccine. Mexico has recorded over 1.2 million cases and 113,000 deaths -- fourth-most globally behind the U.S., Brazil and India.

The United Kingdom, Bahrain and Canada have also authorized the vaccine.

The U.S. Food and Drug Administration has authorized Pfizer and BioNTech's COVID-19 vaccine for emergency use.

President Donald Trump announced the news on Twitter.

The move comes a day after the FDA's advisory committee recommended that the U.S. government authorize the nation's first COVID-19 vaccine for people over the age of 16.

The first vaccine will be administered in less than 24 hours, Trump said Friday night.

Health and Human Services Secretary Alex Azar told "Good Morning America" Friday morning that up to 20 million Americans will be vaccinated this month.

U.S. Surgeon General Jerome Adams urged people to take the coronavirus pandemic seriously and follow public health guidelines as infections and hospitalizations soar across the country.

"I want the American people to know this virus is incredibly unforgiving, cases are going up, hospitalizations are going up, my colleagues are dog-tired and we need you to hang on just a little bit longer because we've got vaccines coming but we want as many people to be alive to get them as possible and a lot of that is going to depend on your behavior," Adams told ABC News chief anchor George Stephanopoulos in an interview Monday on "Good Morning America."

Although "more people than ever are wearing masks," Adams said he's "very" concerned by the number of people who still "don't understand how much spread is occurring by people who don't have symptoms."

About 20 million "full doses" of COVID-19 vaccines will be available by the end of the year, according to Adams, who urged every American to be immunized against the virus as soon as a vaccine is authorized and made available.

"It's a way that we can ultimately end this pandemic, but it doesn't matter if people won't get the vaccination," the surgeon general said. "We know that vaccine levels are only about 50% for adults for flu and they go down to about 40% for African-Americans."

Adams said he is working with historically black colleges and universities as well as faith communities to bolster vaccine confidence among all populations. The White House is also hosting a vaccine summit Tuesday, he said.

"One thing you can all do right now, it's national flu immunization week, get your flu shot because half a million people were hospitalized last year with the flu," Adams said. "We simply can't afford for that to happen this year with hospitals being overwhelmed."

The surgeon general said the current surge in infections across the country "is different than earlier surges," because it's not about a lack of masks or personal protective equipment, nor is it due to a lack of testing.

"It's really about health care capacity, and certain places are just being overwhelmed," he said. "So we know that we can actually help them with their health care capacity by immunizing their health care staff. We're going to leave it up to the states, but we're going to give them guidance."

Adams noted it's also important to vaccinate those who are most likely to die from COVID-19.

"We know that 40 to 50% of the deaths are occurring in people who are in longterm care facilities who are older," he said.