As the summer holidays wind down around Greece and people head home for work and the start of a new school years, health authorities are anxious that many may have COVID-19 in their baggage and further spread the pandemic.

Vana Papaevangelou, an infectious disease expert and member of the New Democracy government's advisory committee on the pandemic said returning holiday makers should do self-tests, said Kathimerini.

“We entreat everyone coming back (from holiday) to take a self-test before they return and to be particularly careful for at least seven to 10 days in their contacts at work, socially and at home,” she told reporters at the Health Ministry’s daily public briefing.

There's especially worry that the biggest carriers of the Coronavirus and the Delta Variant from India that now makes up almost 90 percent cases – and is spiking hospitalizations, people in Intensive Care Units (ICUs) and deaths – will be those coming back from islands.

Vaccinations are not mandatory in Greece, except for health care workers so far, and even tourism workers – including on islands where visitors must show proof of being inoculated or free of the virus – don't have to have the shots.

That has led to a spike in cases on islands with no explanation why the workers there weren't required to be vaccinated. “We expect a significant risk of transfer of the viral load to mainland Greece,” she said, reported Kathimerini.

That referred to cases shown in human waste in the prefecture of Attica, which includes the capital Athens, the numbers rising although some 20 percent of the population there went to their village homes or islands in August.

COVID-19 cases in hospitals have leaped 25 percent in the two weeks when most people in Athens and the surrounding area were on vacation, with a big jump too for those over 65 years old, she said.

The Eleftheria (Freedom) vaccination program has hit the wall at 61 percent of of the country's population of 10.7 being fully protected but health authorities said at least 70 percent is needed to slow the pandemic, and maybe 80-85 percent.

Students, teachers and staff who aren't vaccinated will have to take two molecular test weekly at their own cost, which the government said would be 10 euros ($11.75) each time but private diagnostic clinics want 20 euros ($14.10) for their exam work.