ATHENS – Greece's expectations for a rebound tourism summer are fading over surging COVID-19 cases – driven by the Delta Variant – and not requiring workers on islands to be vaccinated.

Prime Minister and New Democracy leader Kyriakos Mitsotakis so far has mandated shots only for health care workers, although teachers could be next in line, and a plan to vaccinate the entire population of dozens of islands didn't include the most popular, such as Mykonos and Santorini.

After the pandemic and ban or limits by some countries on residents visiting Greece held down arrivals in May and June, they began to jump again in July, with hopes of reaching half the numbers in a record 2019 year.

The increase in cases led the US Center for Disease Control and Prevention (CDC) to warn against travel to Greece, where health officials are worried a jump on islands – which led the European Centre for Disease Control to declare them deep red and risky, could hold down the numbers although there's still no movement to vaccinate tourism workers who make up nearly half the cases there.

Data on bookings for August and September were far better but now a fourth wave of the Coronavirus has kicked in and only half the population – far less tha the 70 percent mark needed to beat back the crisis – has been fully vaccinated.

The biggest number of visitors have come from Germany, some 600,000 of them in a major market for Greek tourism, a 60 percent jump from the May-July period of 2020 when the pandemic raged and fear dominated.

Next are those from Poland, with 280,000 arrivals marking the amount for all of 2020, then the French, with 275,000 and Romanians at 185,000 said Kathimerini, with Americans not coming in the numbers expected after being allowed.

Restrictions set by the United Kingdom, which would require residents who go to Greece to face a quarantine on return, essentially shut down that key market, but bookings are up for August and September, the report said.

Only 125,000 Americans, including the Greek-American Diaspora that was locked out in 2020, have come although they don't face restrictions for doing so although Greece has a number of requirements, including filling out documents and proof of vaccination, a negative PCR test or having recovered from COVID.

It looks better at some regional airports, especially the wild party island of Mykonos where the government, apart from a brief curfew and ban on music, has allowed it to keep going on during the pandemic, spreading the virus.