The commission, responsible for safeguarding the interests of patients, has appointed Kavanagh to replace Stacey Adams, who has left without a job to go to after two and a half years.
Reporting to chief executive Anna Walker, Kavanagh will lead a team of 25, covering media, publishing, internal comms and events, as head of comms. She said moving from the private to public sector had become less unusual, with differences between the two narrowing.
"Many people are moving from the private to public sector, especially in health where there is much involvement from the private sector. There is now less of a division between the two of them ," she told PRWeek.
The commission will merge with the Mental Health Act Commission and the Commission for Social Care Inspection in 2008, following a review of the Department of Health's arm's-length bodies. Kavanagh said it was "too early to say" if the merger will mean job cuts.
Kavanagh was Pfizer's director of corporate and public affairs for six years before leaving in 2004. During this time she was a non-executive director at the Department for Culture, Media and Sport.