Dr Rosemary Geller, who has held the position since 2005, has been off work since late last year because of a chronic back condition. It is not known whether she will remain in the Island or return to the UK.
Her duties had included recommending how to improve the health of the Island population, protecting Islanders from infectious diseases and developing health services.
Her deputy, Dr Susan Turnbull, who has been running the Department of the Medical Officer of Health since Dr Geller was initially signed off, will continue covering the role until a longer term plan is finalised.
