His father was a merchant wholesalesman, one of the wealthiest men in the town, until 1945, when the new communist regime of the former Yugoslavia confiscated all of his property.

After he finished his studies there, he was appointed as junior assistant in physiology of domestic animals at the Faculty of Agriculture and Food in Skopje.

[5] In 1960, he specialized with a Master of Science in physiology and biochemistry at the University of Belgrade with help from his mentor, Professor Bozidar Nikolic.

After his master's studies, Efremov defended his doctoral thesis, titled "Fetal and Adult Animal Hemoglobins," in September 1963 at the University of Belgrade.

After he returned from the United States two years later, he was appointed to a position at the Macedonian Academy[6] of Sciences and Arts, where he founded the Research Laboratory for Genetic Engineering and Biotechnology,[7] and where he also served as director.