Editor’s Note: Holly Thomas is a writer and editor based in London. She tweets @HolstaT. The opinions expressed in this commentary are solely those of the author. View more opinion articles on CNN.

CNN  — 

“From day one of the organization of the Adria Tour, we’ve been following the rules and the measures that have been regulated by government institutions and health public institutions,” Novak Djokovic said last week before the Croatia leg of Adria, a tennis tournament he’d organized for charity. “We’ve been through all these processes and the result of it all was amazing.”

Holly Thomas

Things swiftly became less amazing on Tuesday this week, when the world number one announced that he and his wife Jelena had both tested positive for coronavirus.

Djokovic is now the fourth leading tennis player to announce that they have been infected with the disease since taking part in the now-canceled Balkans tournament.

“Everything we did in the past month, we did with a pure heart and sincere intentions,” Djokovic said in a statement Tuesday, apologizing after announcing that he was sick. “Our tournament was meant to unite and share a message of solidarity and compassion throughout the region.”

But as he has now discovered, Covid-19 doesn’t care how pure anyone’s intentions are – and following the letter of a region’s guidelines is no guarantee of safety when dealing with a virus which seizes any opportunity to disseminate, and remains far from fully understood. As surging cases across the US and in countries around the world are demonstrating every day, a preemptive assumption that business can continue as usual can have devastating consequences.

Despite criticism from other leading tennis players, Djokovic had previously emphasized the credibility of holding the tournament even as Covid-19 enveloped countries worldwide. He stressed that conditions in Serbia and Croatia, where matches were due to be held, were very different to places worse affected, and thus it was “very difficult” to think of international standards.

Though he didn’t personally make the comparison, the optics of the event were more favorable than others. Hosting a charity exhibition might appear more morally excusable than say, a political rally in a high-risk American state against the express advice of one’s own coronavirus task force. But optics or no, it was an event which invited huge crowds to gather in the middle of a pandemic, and therefore – as might seem very obvious to anyone who’s spent the last few months locked down in a country with snowballing death rates – put everyone present in danger.

In Djokovic’s limited defense, holding the tournament did not break any rules. Though stands at the Novak Tennis Centre in Belgrade were reportedly packed for the first match earlier this month, Serbia had already lifted the ban on outdoor public gatherings, and the government had recommended people stay only three feet apart. Based on this, one could argue that there was little cause for concern. The fact that he was following Serbia’s comparatively relaxed “rules and measures” made it possible for Djokovic to abdicate personal responsibility for deciding whether the event he’d assembled was safe - which he readily did.

“You can also criticize us and say this is maybe dangerous, but it’s not up to me to make the calls about what is right or wrong for health,” he retorted, following criticism of the packed crowd at the first game. “We are doing what the Serbian government is telling us.”

But as we’re seeing more and more, too often a relaxation of measures is swiftly followed by another surge of infections. Countries including China and Germany have renewed lockdown measures in some areas following the emergence of new clusters of cases, and across the US, states are seeing spikes since restrictions have lifted.

For all Djokovic argued that the situation seemed OK in the countries he’d planned to play in, he might have heeded the signs from countries like Sweden, which for a while looked like it was getting away with minimal restrictions, but is now suffering rising casualties. As British tennis star Dan Evans said following the initial reports of Grigor Dimitrov and Borna Coric testing positive during the tour: “It (hosting a tennis tournament also featuring private player parties) is a poor example to set.”

It isn’t only the virus’s potential to resurrect itself that governments – and individuals including Djokovic – have miscalculated. Again and again, things the public – and governments – have believed to be true about coronavirus have been proven wrong.

Just three or four months ago, it was a common assumption that relative youth would prove defense enough in the vast majority of cases. Now, infections are soaring among those in their 20s and 30s, and the median age of a Covid-19 patient in Florida is now 36, down from 65 at the beginning of March. The initial belief that children were relatively safe from the virus dissipated as more potential complications were discovered, and the World Health Organization has U-turned on its early recommendation not to wear facemasks unless sick or caring for the sick, encouraging the public to wear them wherever the virus is spreading.

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    Djokovic has said that he is “extremely sorry for every case of infection,” since the abortive Adria tournament. But as the fiasco has demonstrated, good intentions and favorable guidance provide no immunity from coronavirus. As many countries continue to lift restrictions around the world and cooped-up populations adjust to lives less encumbered by them, they would do well to remember the example of the best tennis player in the world, whose career has never been more under threat thanks to his impatience to get back on the court.

    This op-ed has been updated to refer correctly to Dan Evans.