Last week the Centers for Disease Control changed its travel guidance, saying that fully vaccinated people can travel safely without quarantining or testing. But the news came with a warning – the agency still discourages all non-essential travel.

This mixed message reflects the hope and caution of this moment: a record number of Americans got vaccinated this past weekend, state and local governments are lifting restrictions on businesses, but Covid-19 cases have begun to tick up again. Hospitalizations are also on the rise, and experts are expressing concern about the spread of new variants. Meanwhile, a debate is brewing over so-called vaccination passports and how and whether they should be used.

Dan Diamond is national health reporter at the Washington Post. He explained why this is such a tricky moment in the pandemic for Americans to understand, and the Biden administration to explain.