The US Rejoins the WHO Under the Biden Administration — Here's Why That's Important 1K Shares Rejoining the World Health Organization (WHO) was one of Joe Biden's first moves as president, coming amidst a flurry of day-one actions and executive orders that included re-entering the Paris Climate Agreement and mandating the use of face masks on federal property. While moves like enacting mask mandates and ending the so-called Muslim ban on travel from some predominantly Muslim countries have a clear and immediate effect, returning to the WHO has a less direct impact. But according to Anthony Fauci, MD, the new head of the United States's delegation to the WHO, it's a crucial action for the global fight against COVID-19.