Health trusts across England were sent details of an IT security patch that would have protected them from the crippling ransomware attack, NHS Digital said.
Large swathes of the NHS have been paralysed by the cyber attack, which hit 200,000 victims in 150 countries around the world.
But NHS Digital said it had made health trusts aware last month of IT protection that could have prevented the attack.
Nissan's UK plant in Sunderland has been hit by a "major" cyber attack which also struck the NHS.
The car manufacturing firm announced on Saturday that the ransomware assault had affected "some" of its systems at the Tyne and Wear hub.
The Newcastle Evening Chronicle reported that the plant's systems were first affected on Friday night, briefly halting production.
A statement from a Nissan spokesperson said: "Like many organisations, our UK plant was subject to a ransomware attack affecting some of our systems on Friday evening.
"Our teams are working to resolve the issue.”
Hospitals have stopped diverting patients following last week's cyber attack which crippled many NHS Trusts' IT systems.
A young computer expert from north Devon who was hailed a hero for helping to stop the global cyber attack said he was just "doing my bit".
One surgery has no access to medical records.