It also was notable for Johnson's unabashed praise of two immigrants. He has staked his career on Brexit, a cause closely bound up with the desire of many in Britain to control immigration, and his words could mean a change in his government's tone.
"I will never, ever be able to repay you and I will never stop thanking you," added Johnson, who spent three nights in intensive care at St Thomas' Hospital.
Johnson called the NHS "unconquerable" and "the beating heart of this country" after seeing its response to the outbreak first-hand. He lauded the courage of everyone from doctors to cooks.
As the 55-year-old Johnson recuperated at his country estate, the video continued to be shared on social media, sweeping across a nation in the fourth week of a lockdown.
The direct and highly personal message could make it harder for him to stonewall the doctors and nurses who saved his life when the NHS asks for more resources in the future, said Jill Rutter, a senior fellow at the Institute for Government in London.
"That video yesterday — everyone says that is Boris like they've never seen him before championing the NHS," Rutter said. "He would pay a massive political price for hypocrisy if he appeared to be doing anything that suggests scepticism about the NHS or its performance after that speech.''
But Johnson's praise for the nurses from New Zealand and Portugal also underscored that it is immigrants who have helped hold up Britain's NHS. Up to a quarter of the UK's hospital staff were born overseas.
Dr Chaand Nagpaul, chair of the council of the British Medical Association, urged Johnson's Government to grant permanent residence to the families of overseas medical staff who die in the pandemic and highlighted that many international doctors and health professional pay a surcharge for their own care because of their immigration status.
"It is unfair to expect doctors currently outside of the UK who are willing to come to help in the crisis and other international doctors and healthcare workers already in the UK, who are prepared to risk their lives while providing care in the NHS, to pay for that care should they themselves need it," Nagpaul said.
Though the NHS hasn't yet been overwhelmed by the outbreak, experts said austerity-fuelled cuts have hurt its ability to respond.
"The infectious diseases specialty has been decimated in the last 10 years," said Allyson Pollock, director of the Newcastle University Centre for Excellence in Regulatory Science. "Our local health authorities have had a 50 per cent cut in their budgets and no longer have responsibility for infectious disease control, so we have no good data on what's happening at the community level."
Pollock said the structural changes in the health service have reduced the number of available beds, harmed its ability to chart the epidemic and drained it of expertise.
Other experts noted that pandemic preparedness has taken a back seat to other problems in recent years, such as the effects of Brexit.
Martin McKee of the London School of Hygiene and Tropical Medicine noted that in the lead-up to Brexit, the department of health was deploying about 80 per cent of its staff to working on potential problems linked to an exit from the European Union without a deal.
Supply chains were clearly not ready. Chronic problems with getting personal protection gear have alarmed doctors and nurses, threatening to cripple the response.
Chris Hopson, chief executive of NHS Providers in England, which represents hospital trusts, told the BBC that the supply of gowns was precarious because of delays in shipments and because some of the products failed safety tests.
"This is all really hand-to-mouth in terms of gown delivery, and we need to get to a more sustainable supply,″ he said.
There were other problems, too. The government has been criticised for its slow start in increasing coronavirus tests, especially compared with Germany, which has tested far more widely and recorded fewer deaths.
The UK Government has promised to increase capacity to 100,000 tests a day by the end of April. That figure is now 18,000, and the government says it is quickly increasing the number of testing sites – including 23 drive-thru centres for healthcare staff and their families.
As it considers easing the lockdown this week, government ministers will be mindful of relaxing measures too soon, despite the economic risks. Treasury chief Rishi Sunak warned last month that the UK could fall into recession due to the disruption caused by the outbreak.
There was a sense though, that the end of Johnson's hospitalisation boosted morale.
"Today I'm feeling incredibly lucky," Johnson said.
- AP