United States President Donald Trump's prime-time address to the nation about the spread of the coronavirus began with two unforgettable words.

"Oh f***".

CSPAN, the channel that airs all matters of national importance from Congress and the White House, had started its broadcast a few minutes early.

On screen, there was just a title page with the words "Presidential Address". Trump couldn't be seen, but his unmistakable voice could be heard. Clearly.

"Oh, oh! I got a pen mark," he said amid frantic shirt-rubbing sounds.

"Anybody got any white stuff?"

But he'd need much more Liquid Paper before the night was through.

A travel ban 'without consultation'

Italy has been one of the hardest hit by coronavirus, prompting Trump's travel ban. ( Reuters: Flavio Lo Scalzo )

Without warning and with next to no consultation with foreign allies and even key members of his own administration, Mr Trump announced a travel ban for Europe.

"To keep new cases from entering our shores, we will be suspending all travel from Europe to the United States for the next 30 days" he read from the tele-prompter.

But crucially, his statement didn't clearly state that the travel ban only applies to foreign citizens.

Nor did his speech indicate what countries in Europe would be included. That was later clarified, where it was revealed the restrictions do not apply to all of Europe, but to the 26 countries which make up the Schengen Area, which have abolished all passport and border controls among each other.

While he did eventually speak of "exemptions" for Americans who've undergone appropriate screenings in his speech, by that point, understandably, thousands of American citizens in Europe were sent into a spin.

As was the rest of the world.

The European Union too was caught by surprise, prompting them to issue an extraordinary public rebuke.

"The coronavirus is a global crisis, not limited to any continent and it requires cooperation rather than unilateral action," it said in a statement.

"The European Union disapproves of the fact that the US decision to impose a travel ban was taken unilaterally and without consultation."

Words (and mistakes) matter

As Trump's address to the nation continued, there was another major blunder.

"These prohibitions will not only apply to the tremendous amount of trade and cargo, but various other things as we get approval," Trump said.

He was wrong.

It seems Trump had inadvertently added one hugely consequential word: "only".

The sentence should have read: "These prohibitions will not apply to the tremendous amount of trade and cargo, but various other things as we get approval."

The markets sank like a stone. Again.

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Later, Trump took to Twitter to try and Liquid Paper over the mess.

"… Very important for all countries & businesses to know that trade will in no way be affected by the 30-day restriction on travel from Europe. The restriction stops people not goods."

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During the speech, he also wrongly claimed health insurance companies would "waive all co-payments for coronavirus treatments". But all they'd agreed to was testing.

And Trump claimed his administration is "making antiviral treatments available in record time," when there are as yet no approved antiviral treatments for COVID-19.

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Trump's been seeing crowds and shaking hands … until now

Trump is now taking the crisis seriously after down-playing it for weeks.

He ignored warnings from his administration's top medical experts about avoiding crowds and even shook hands with supporters on the tarmac after touching down near Orlando this week.

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Trump's been boasting about the relatively low number of cases in the US, when the likely reason for that is the lack of readily available and functional testing kits.

The US Centres for Disease Control is recommending people stop shaking hands — which is difficult for politicians running for president. ( Reuters: Lucy Nicholson )

After seeking political advantage by blaming his opponents, and even the previous administration, for the problems the US has faced, he's now urging everyone to unify as "one nation and one family".

"We must put politics aside" he declared from the Oval Office.

Democrats are also struggling with coronavirus

Bernie Sanders' supporters regularly hug him during campaign rallies. ( Reuters: Jonathan Ernst )

Over on the Democrats side, shaking hands with voters has been replaced by elbow or fist bumps, but only after weeks of much closer contact with supporters.

There's even been some talk of moving the whole show online, the world's first 'virtual campaign'.

Joe Biden and Bernie Sanders have cancelled all major campaign rallies as they continue to travel the country ahead of more primary elections.

They'll debate on Sunday (local time) without a live audience, at the request of both campaigns.

"If coronavirus has the lasting impact that we all fear it will, it will also dramatically reshape the way a presidential campaign unfolds," veteran Democratic strategist and former spokesman for Hillary Clinton's campaign Jesse Ferguson told Associated Press.

Far from a grand victory speech, Joe Biden spoke in a largely empty room to just a handful of close staff. ( Reuters: Brendan McDermid )

How will coronavirus impact the election?

Voting could present an even bigger problem. And then there's the candidates themselves.

All three have been criss-crossing the nation, meeting with hundreds of potentially infected people.

Joe Biden says he'll host more 'virtual events' to avoid crowds during the coronavirus pandemic. ( Reuters: Brendan McDermid )

But it seems unlikely that they will be able to keep conducting the normal activities of a campaign.

All of them are right in the danger zone for risk of serious illness or death from COVID-19.

Bernie Sanders is 78-years-old with a heart condition.

Joe Biden is 77.

Trump is 73.

While the true impact of coronavirus on the US election is impossible to predict, it appears that it is already affecting the campaign in a substantive way.