Dr. Anthony Fauci spoke about the possibility of future NIH collaboration with labs in China - like the Wuhan labs - after officials overseeing an intelligence review into the origins of the coronavirus now believe the lab leak theory is at least a credible explanation for Covid-19's origins.

The US is now averaging more than 43,000 cases of Covid-19 a day as the Delta variant fuels a 65% jump in cases. CNN's Polo Sandoval reports.

Former NFL player Orlando Scandrick, who says he is vaccinated and pro-vaccine, criticized a memo released by the league that says if a game cannot be rescheduled and is canceled due to a Covid-19 outbreak among unvaccinated players, that team will have to forfeit and will be credited with a loss.

New York City Mayor Bill de Blasio says it's time to do something different to combat the spread of Covid-19 and will require all healthcare workers to show proof of vaccination or get tested weekly as a condition to show up to work.

The American Academy of Pediatrics released new Covid-19 guidance for schools that supports in-person learning and, among other things, recommends universal masking in school of everyone over the age of 2.

Opioid overdose deaths rose 30% last year, making 2020 the year with the highest number of overdose deaths ever recorded in the US, according to the CDC. CNN's Elizabeth Cohen reports on this health crisis that continued to plague the US amid the Covid-19 pandemic.

A new data analysis identifies clusters of unvaccinated people, most of them in the southern United States, that are vulnerable to surges in Covid-19 cases and could become breeding grounds for even more deadly Covid-19 variants. CNN's senior medical correspondent Elizabeth Cohen reports.