Vida Mary Katie MacLean was born at Whangaehu, near Whanganui, New Zealand, on 4 November 1881. Registered at birth as Katie Mary Vida McLean, she was the daughter of Julia Williamson and her husband, Finlay McLean, a farmer. Vida grew up in the Whanganui district and was educated mostly in private schools. She undertook her nursing training at the Whanganui Hospital between 1905 and 1909. A competent student, she was ranked 11th out of the 50 nurses in New Zealand who passed the state examinations in December 1909.
After working at the Wanganui Hospital until November 1910, Vida moved to Wellington to do her midwifery training at St Helens Hospital. At the end of 1912 she again excelled in the state examination: along with another candidate she gained full marks in both the written and oral sections, described at the time as a unique achievement. She spent a short time as the acting sister of Te Waikato Sanatorium at Cambridge, and by July 1913 had returned to Wellington to be sub-matron of St Helens Hospital. This was the first of many managerial positions she would hold in both the civilian and military nursing services.
Vida MacLean served as a nurse throughout the First World War. From August 1914 to March 1915 she was one of seven nurses attached to the New Zealand Expeditionary Force in Samoa. Soon after returning to New Zealand she joined the first 50 nurses leaving for overseas duty with the newly formed New Zealand Army Nursing Service. Initially posted to Egypt, MacLean took charge of the isolation block at the 300-bed New Zealand base hospital in Cairo, working with Dr Agnes Bennett. This hospital was soon expanded to 650 beds to accommodate the constant influx of soldiers with battle injuries and diseases such as gastroenteritis and dysentery.
In June 1916 MacLean was transferred to the complex of hospitals in southern England that made up No 1 New Zealand General Hospital at Brockenhurst. There she took charge of the Forest Park section, which was a hotel converted into a hospital of 100 beds. Promoted first to matron of the New Zealand Convalescent Hospital at nearby Hornchurch in January 1917, she became matron of No 1 New Zealand General Hospital in April. Both hospitals were huge. Hornchurch had over 1,000 beds, while Brockenhurst held over 1,500, and at peak use during 1918 cared for more than 1,600 injured and sick New Zealand soldiers. For soldiers injured in France and shipped to Southampton, reaching the New Zealand hospitals in southern England was a haven after the misery and fear of the front. In March–April 1919 Vida took part in an educational course at St Thomas's Hospital, London. She sailed home to New Zealand in May.
During the war MacLean was twice mentioned in dispatches. She was awarded the Royal Red Cross, second class, in 1916, and first class in 1918. On returning to New Zealand she was matron of the Trentham Military Hospital until October 1920. Then, in partnership with another nursing sister, Fanny Wilson, she took over and ran the Malifa private hospital in Willis Street, Wellington.
Around July 1925 Vida MacLean, then aged 43, embarked on a different phase of her nursing career, one that focused on health promotion under the auspices of the Plunket Society. After completing a training course at the Karitane–Harris Hospital, Dunedin, she became matron of the Mothercraft Home in Wellington. She was soon put in charge of antenatal services for the Wellington area. In late 1927 she was appointed matron at the Karitane Hospital in Auckland and in 1929 moved to Sydney to supervise Plunket work and the training of nurses. She was employed at her previous position in Auckland in 1930, then returned to Sydney. From May to December 1936 she worked at four centres in the Wellington province before transferring to Adelaide as matron and adviser to the Truby King Mothercraft Society.
In 1938 Vida MacLean's Plunket work took her to India where she was to start a mothercraft clinic in Calcutta. However, the Second World War intervened and she joined the Indian Military Nursing Service. The clinic, the Truby King Mothercraft Centre, was opened in 1948 with MacLean as first matron. She retired, aged 73, in April 1955 and returned to New Zealand. Her retirement years were spent in Whanganui, where she lived with her sister Edith until Edith died in 1964. She never married and died in Wanganui Hospital on 1 July 1970. Although Vida MacLean's death certificate records her occupation as an ex-servicewoman, she had, above all, been a nurse – one of the most eminent of her time.