Born in Argentina in 1902, Fernández was an active and eminent physician in leprosy research and described the early (Fernandez) reaction to lepromin. He was president of the International Leprosy Association (ILA) from 1963 to 1965 and for 25 years occupied the chair of dermatology at the Medical School of the University of Rosario, Argentina. In 1961 he became the honorary president of the Argentine Society of Leprology.

He was interested in many aspects of leprology and in 1939 began using BCG vaccine to convert the Mitsuda reaction to positivity. His work raised hope that such a vaccine might prevent leprosy.

He was associate editor of the International Journal of Leprosy and contributing editor of several scientific journals. He maintained close relations with WHO as a consultant to the Expert Committee on Leprosy and received assistance from WHO for research on the standardisation of lepromin and transmission of M. leprae to laboratory animals.

International Journal of Leprosy, Centennial Festskrift edition, Vol 41, No 2. 1973.