Perhaps no other industry has been hit harder by the Covid pandemic than global travel and tourism, with planes grounded, resorts closed, and care-free vacations a distant memory for most of us.

Some European countries, such as Greece, Spain, and Portugal, rely on tourism to boost economic growth, with the success or failure of the season affecting the fortunes of thousands of businesses, livelihoods, and communities.

As Covid vaccines were being distributed throughout Europe, hopes for a rebound in summer tourism were high. Instead, the season appears to be highly uncertain as the delta variant spreads across Europe, prompting a slew of varying rules and restrictions, traffic-light systems designating country risk, as well as possible quarantines and vaccine entry requirements.

In more ways than one, traveling within Europe these days is not for the faint of heart. As the highly infectious delta variant has swept the globe, the Covid infection rate has risen across the region.

As with the previous alpha variant, which delta has now supplanted, the United Kingdom was a portent of doom for the rest of Europe. Britain experienced another Covid wave at the beginning of the year, caused by the alpha variant, and is now experiencing another wave with delta.

Despite efforts on the continent to contain the strain, it has spread, with the strain now accounting for the majority of new infections from country to country.

After both countries reopened their nightclubs in late June, only to reverse course two weeks later, the Netherlands and Spain have seen significant increases in cases, which have been attributed largely to the nighttime sector. France declared earlier this week that it had entered the fourth wave of the pandemic, with government spokesman Gabriel Attal sounding the alarm.

Tourism and airline stocks were hit hard at the start of the week as global markets fell sharply on renewed concerns about the global recovery. EasyJet and Ryanair, two low-cost European airlines, were among the stocks that fell sharply. EasyJet shares, for example, were trading at 842.20 pence on Friday but had dropped to 758.20 pence by Monday afternoon.

Anyone planning a last-minute trip to Europe this year should brace themselves for a frequently confusing, complex, and stressful experience — and that’s before you’ve even stepped off the plane.

Visitors from the United Kingdom are permitted to enter Greece if they can show proof of a negative Covid-19 PCR test performed within 72 hours of arrival, or proof of a negative rapid antigen test performed by an authorized lab within 48 hours of the scheduled flight, or proof of two doses of a Covid vaccine completed at least 14 days before travel.

However, before you even arrive in Greece, you must complete a passenger locator form by 11:59 p.m. (local time) the day before, stating your vaccination status, vacation address, and next of kin. Then, before returning to the UK, holidaymakers must take a PCR test and fill out another passenger locator form, and then, within two days of their return, take another PCR test or be quarantined for ten days.

Greece, like its European neighbors, has seen an increase in Covid cases as the economy (particularly the island nighttime economy) has opened up. Nonetheless, the daily number of cases appears to be low when compared to, say, France or the United Kingdom. Greece reported 2,972 new cases on Wednesday, 19 of which were discovered after border checks.

On Wednesday, Wolfango Piccoli, co-president of risk consultancy Teneo Intelligence, noted that the resurgence of Covid in Greece “poses new challenges, particularly with regard to another meager tourism season and the economic consequences that will follow,” putting pressure on Prime Minister Kyriakos Mitsotakis.

So far, he claims that only about 120,000 of the estimated 980,000 Greeks in this age group have been immunized.

Piccoli noted that vaccination rates in the general population have reached nearly 52 percent for at least one dose of the vaccine and nearly 44 percent for complete vaccination, but that “recently slower uptake has raised doubts about whether the government can achieve its target of vaccinating 70-75 percent of the adult population by the end of the summer.”