Vida Mary Katie MacLean left Wellington for Samoa on 15 August 1914 with five other nurses as members of the Expeditionary Force Advance Party. The NZANS had not been established at that time so the nurses were attached to the New Zealand Medical Corps (NZMC) as New Zealand Army Nursing Service Reserve (NZANSR) and were issued with service numbers which were later replaced with NZANS numbers.

MacLean Returned to New Zealand to join the first contingent of 50 nurses to leave for Europe, in April 1915 on board SS Rotorua. Initially posted to Egypt, MacLean took charge of the isolation block at the 300-bed New Zealand base hospital in Cairo.

She was transferred to England in June 1916 where she became matron of the New Zealand Convalescent Hospital at Hornchurch in January 1917 and then of the No.1 New Zealand General Hospital at Brockenhurst in April. Both hospitals were huge. Hornchurch had over 1000 beds, while Brockenhurst held over 1500, and at peak use during 1918 cared for more than 1600 injured & sick New Zealand soldiers. During the war she was twice mentioned in despatches (MID).

In 1925, MacLean became active in Plunket, taking the work to India in 1938 where she was to open a Mothercraft Clinic in Calcutta. WW2 intervened, during which she served with the Indian Military Nursing Service. The clinic, the Truby King Mothercraft Centre, was opened in 1948 and MacLean became first matron.

MacLean Returned to NZ in 1955 aged 73.She died in Wanganui in April 1970.

NB: From Te Ara and from While You're Away: New Zealand Nurses at War 1899-1948 by Anna Rogers