The United States still leads the world in the total number of persons vaccinated and on Friday, became the first country to vaccinate 100 million people.

The U.S. Centers for Disease Control and Prevention announced 101.8 million Americans have been inoculated at least once since vaccinations began on Dec. 14, 2020. This number covers almost 40% of the country's total number of adults. Nearly 58 million of these people are fully vaccinated.

In addition, 3.9 million persons were vaccinated Friday, a new daily record, according to Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases.

The records also mean almost 60 million Americans are fully vaccinated with either two doses of the vaccines developed by Pfizer/BioNTech and Moderna, Inc., or one dose of Johnson & Johnson's vaccine.

Some 39.2% of U.S. adults have been incoculated at least once, including 74.4% of the country's senior citizens, who face an especially high risk of serious COVID-19.

CDC has updated its guidelines to say vaccinated people can now travel without observing quarantine but should continue to wear masks. It did, however, correct a statement made by its director, Dr. Rachel Walensky, who earlier misspoke by saying people vaccinated against COVID-19 won't become infected with the coronavirus or spread it to others.

"We're vaccinating so very fast, our data from the CDC today suggests, you know, that vaccinated people do not carry the virus, don't get sick, and that it's not just in the clinical trials but it's also in real world data," said Walensky in her original statement.

CDC later said Walensky was speaking broadly when she said this.

"It's possible that some people who are fully vaccinated could get COVID-19," said a CDC spokesman. "The evidence isn't clear whether they can spread the virus to others. We are continuing to evaluate the evidence."

Johnson & Johnson on Friday said it's started testing its vaccine on adolescents. The single-shot vaccine will first be tested on a small number of 16 and 17-year-olds as part of an ongoing study in September 2020.

After initial data from the older teens becomes available, the trial will be gradually expanded to a larger group of younger adolescents from 12 to 15.

Last week, President Joe Biden said 90% of adults in the U.S. should be eligible to be inoculated by April 19. He also urged Americans to keep wearing masks and take the other proven precautions to stop the pandemic.

"I plead with you. Don't give back the progress we've all fought so hard to achieve," said Biden.

"We need to finish this job. We need every American to buckle down and keep their guard up in this home stretch."