The province says about 13,000 new individuals, on top of the 7,500 that were identified earlier this year, may have had their medical information viewing inappropriately.
The Ministry of Health is contacting all affected individuals by letter to inform them of the incidents.
The province is saying the PharmaNet breach, which targeted physicians, medical clinics and service vendors, is alleged to have been the result of cybercrime and an arrest has been made by Vancouver police.
In order to mitigate the risk of fraud and identity theft, the government is offering credit monitoring at no cost to all affected individuals.
More robust security measures have also been implemented within the system.
