With Europe in the middle of the strangest summer holiday season for many decades, it seems a good time to pause and attempt to take stock of where we currently stand.

With the world's grimmest scoreboard having ticked relentlessly up to more than 766,000 deaths and close to 22 million confirmed cases, it seems very unlikely now that the virus will have been tamed by the time that the crunch decisions about the Olympics will need to be taken.

With so many asymptomatic carriers, the trends we witness in coming months look likely to depend on a) the short-term trade-offs Governments make between keeping the lid on the virus and reopening domestic economies; and b) how rigorously prophylactic measures such as masks and social distancing are implemented and enforced.

In Japan, daily new cases have lately been running at around 1,000 a day, while the coronavirus death toll from a relatively old population of 127 million has edged up to about 1,100, far lower than in many other countries.

If these statistics do not markedly worsen over the next few months, you might imagine that an Olympic Games of some sort in Tokyo is at least possible.

You might also imagine many in the local population fretting about the possible consequences of a short-term influx of foreigners from countries far worse hit than Japan.

Regarding a vaccine, it looks likely that certain formulations will be confirmed in coming months as raising antibodies, and hence aiding COVID resistance, in most of those who take them.

But decisions on Tokyo will probably need to be made before completion of all the trials that would normally be required for a new medicine to be made widely available.

This might give rise to questions/arguments regarding the point at which it becomes acceptable to make a vaccine available even if doubts about its effectiveness and possible side-effects still linger.

I wonder whether those expecting to compete or work at the Games, or perhaps just to attend them, might be offered a vaccine shot – or maybe even, in some cases, compelled to have one – while signing a disclaimer acknowledging the risks and undertaking not to take legal action should they fall ill.

If that is the case, I would expect some competitors to have second thoughts about participating, especially those with young families.

It is ironic that one of the leading vaccine projects should come from Russia, a nation whose reputation in international sports has been considerably tarnished over the six-and-a-half years since it hosted the Winter Olympic and Paralympic Games in the Black Sea resort of Sochi.

It is hard to imagine how sports leaders might react if it turned out that a vaccine called Sputnik V, developed in Russian laboratories by a Government-controlled institute, turned out to offer the best chance of salvaging their four-yearly spectacular.

Then again, sport has more reason than most industries to acknowledge the capability of Russian scientists.

The other important trade-offs with a key bearing on whether Tokyo 2020 takes place, and if so in what form, are financial.

The most important Tokyo-related income-streams as far as the International Olympic Committee (IOC) and the Sports Movement are concerned are those pertaining to a) broadcasting rights and b) international sponsorship.

It would be unsurprising therefore if they decided eventually, like Big Football, that the show should go on, even in empty venues, if it meant that the bulk of anticipated broadcasting fees, thought to add up to somewhere in the region of $3 billion (£2.2 billion/€2.5 billion) were safeguarded.  

Absence of ticketing revenue would affect, above all, the Local Organising Committee.

However, the unprecedented success, pre-COVID, of the domestic sponsorship programme, coupled with the natural desire of those associated with what is a major national project to see it executed insofar as this is possible, mean that I would not expect an absence of live spectators to be a make-or-break issue for the Games from the local Japanese perspective either.

The obstacles to an Olympic free-for-all – in the sense of permitting everyone from anywhere in the world who wishes to attend the Games, and has a ticket, to do so – still seem to me pretty daunting. 

But athletes and broadcasters alike would undoubtedly prefer there to be some live spectators.

For this reason I would not be at all surprised to see consideration given to restricting live attendance very largely to Japan-based spectators, especially if stadium capacities are reduced as part of the virus containment effort.

The other financial imponderable which may well influence the decisions that are eventually taken is insurance.

The IOC is known to have some cancellation insurance.

What is not known, except to a privileged few, is how much, and whether there is any risk of a dispute or legal challenge should the IOC decide to make a claim.

Evidently, if the IOC stands to receive an amount equal to the fees it would normally have been paid by rights-holding broadcasters, you might expect it to be disappointed, but relatively phlegmatic in the face of cancellation – though the focus would switch immediately to the Beijing 2022 Winter Olympics and Paralympics just a few months further down the line.

If, however, the IOC's insurance covers only its running costs and not the multi-million-dollar distributions it would normally make following successful delivery of the Games, one might expect International Federations in particular to step-up pressure to make sure that some sort of Tokyo 2020 Olympic event reaches our screens.

I still do not believe that anyone can say with certainty whether Tokyo 2020 will go ahead.

 The points covered here are what Donald Rumsfeld might describe as the "known unknowns".