WHO urges vaccinated travelers to keep taking coronavirus precautions

• WHO Health Emergencies director Mike Ryan noted "there's no guarantee of eliminating or eradicating an infectious disease" — even with a vaccine that has high efficacy as the ones being rolled out are.
• "That is a very high bar for us to be able to get over," he said.

Why it matters: Many tourism-reliant countries, along with the travel and tourism industry, are hopeful that coronavirus vaccinations will see global travel start to make a comeback next year, with international borders reopening.

• The airline industry has developed mobile apps that would receive coronavirus test and vaccination certificates — though Axios' Joann Muller reports that COVID-19 tests will be the passport to travel in 2021

The big questions: In addition to the uncertainty on whether vaccines will stop transmission of the virus or just prevent people from becoming sick, it's still unknown how long immunity through vaccination lasts, per Axios' Alison Snyder, Eileen Drage O'Reilly.

• It's also unknown whether people can have rare or delayed side effects, which could be detected in long-term trials with millions of participants.

By the numbers: COVID-19 has killed nearly 335,000 people and infected over 19.3 million in the U.S., per Johns Hopkins.

• Globally, almost 1.8 million people have lost their lives to the virus and nearly 81.3 million have tested positive.

Worth noting: Ryan said "the likely scenario" for the virus once brought under control is that it will "become another endemic virus that will remain somewhat of a threat, but a very low level threat in the context of an effective global vaccination program."

Go deeper: Coronavirus won't disappear, even with a vaccine