The Vietnam War was fought between North Vietnam (with support from Communist countries such as Soviet Union and China) and South Vietnam (with support from the United States and its allies). The conflicts began in 1954 and became large-scale battles by 1961. Although in a better warfare position, the Peoples Army of Vietnam (North Vietnamese Army) and its allies in the South, Viet Cong, suffered increasing mortality because of malaria epidemics. In some battlefields, the disease would reduce military strengths by half and in severe cases, disable 90% of the troops. North Vietnamese Prime Minister Ho Chih Minh asked Chinese Premier Zhou Enlai for medical help. The year before, party Chairman Mao Zedong had introduced the Cultural Revolution, during which he would close schools and universities and banish scientists and intellectuals. Mao took Hos plea seriously and approved a military project. On 23 May 1967, about six hundred scientists convened. These included military personnel, scientists, and medical practitioners of Western and traditional Chinese medicine. The meeting marked the start of the military-research programme, which received the code name Project 523, after the date (23 May) it launched. The project was divided into three main streams, one for developing synthetic compounds, one for clinical studies (or infection control) and another for investigating traditional Chinese medicine. Classified as a top secret state mission, the project itself saved many scientists from the atrocities of the Cultural Revolution.