Tennis superstar Novak Djokovic's absence from the Australian Open is indicative of a larger problem. CBS News Correspondent Steve Futterman has more in today's "Reporter's Notebook." 

With the demand so high, and testing supplies running low, officials are warning about unapproved COVID testing sites popping up in many cities nationwide. CBS News Correspondent Cami McCormick has more in today's "Reporter's Notebook."

As teachers' unions across the U.S. debate new COVID measures for schools, there are similar concerns elsewhere. CBS News Correspondent Elaine Cobbe has today's "Reporter's Notebook" from France.

There's a new online tool to help you find at-home COVID-19 tests. CBS's Stacy Lyn explains in today's "Reporter's Notebook."

Britain's colorful prime minister, Boris Johnson, is in a peck of trouble over mounting evidence that he broke his own COVID rules. Details from CBS News Correspondent Vicki Barker in today's "Reporter's Notebook."