In the United States, fewer than 60% of the population have been fully vaccinated, one of the lowest rates among wealthy nations.
Aside from wreaking havoc in the travel industry, the clampdown has pounded financial markets and undermined major economies just as they were beginning to recover from the lockdowns triggered by Delta.
Germany said it would bar the unvaccinated from all but essential businesses, and legislation to make vaccination mandatory would be drafted for early next year.
Several countries, including Britain and the United States, were bringing forward plans to offer booster shots, but, like travel bans, they are controversial.