The enterprise-security division of Qihoo 360, one of China's leading suppliers of anti-virus software, said 29,372 institutions ranging from government offices to universities, ATMs and hospitals had been "infected" by the outbreak as of late Saturday.
NHS bosses are confident that south Essex experienced only minor issues, and that patient care was largely unaffected.
Large swathes of the NHS were paralysed by the cyber attack, which hit 200,000 victims in 150 countries around the world.
Shona Robison confirmed to the Scottish Parliament that 1500 computers across 13 health boards were targeted in the ransomware attack.
Mr Matheson discussed the impact of the global cyber attack on Scotland, the multi-agency response and the steps that can be taken to boost cyber resilience across all sectors.
The Mid Essex Hospital Trust, which runs St Peter's Hospital in Maldon, Broomfield Hospital, St Michael's Hospital in Braintree and Christchurch in Chelmsford, worked across the weekend to get affected systems back online.
The Basildon and Brentwood CCG said GP surgeries are also following protocol and working to keep any impact on patients to a minimum - with appointments running as normal.More news: United Nations orders Pakistan not to execute Indian man accused of spying
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"We are grateful for the hard work of staff at trusts and GP practices who are still suffering IT issues but have found ways to work around this, as well as the patience of people who have been affected".
"The advice for patients remains to attend your hospital or GP appointment as usual unless you have been contacted and told not to".
"The work carried out by staff and partners over the weekend was no mean feat so we would like to offer our honest thank you to everyone involved".
NY [U.S.], May 14 (ANI): The World's biggest cyber attack which has hit 200,000 victims in at least 150 countries threatens to create more havoc on Monday when people return to work.
Around a fifth of NHS trusts were hit in the attack, forcing them to postpone operations and procedures over the weekend.
NHS Digital said health trusts across England were sent details of an IT security patch that would have protected them from the attack.