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.

Common questions surrounding the newly authorized Pfizer vaccine include safety for teenagers and the risk of allergic reactions.

Though the final data doesn’t have conclusive data on 16 and 17 year olds because they weren’t enrolled in trials until more recently, the FDA is “very comfortable with the safety profile that was observed in 17 and 16 year olds," Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, told reporters.

Regarding allergies, Marks said 1.6% of the population has had a severe allergic reaction.

Marks said you should notify your doctor if you’ve ever had an allergic reaction to a vaccine and noted that sites that administer the vaccine will have medications on hand to respond to an allergic reaction.

ABC News’ Anne Flaherty contributed to this report.