confirmed the results of a study published in 2015 that awarded the vaccine 100 percent effectiveness after tests on 4000 people in guinea who had been in close contact with ebola patients. however, a study sponsored by the national institutes of health, the food and drug administration and the u.s. department of health and human services, and conducted by researchers from the u.s. national academy of medicine, called the vaccine’s effectiveness in preventing ebola infections into question. in particular, the authors criticized the methodology of the patient trail, and argued that the protection provided by the vaccine may be lower than officially announced. the who approved the vaccine for use in the ongoing ebola outbreak on 29 may 2017. it was announced in may 2017 that the gamaleya research institute of epidemiology and microbiology in russia would deliver 1000 doses of an independently produced vaccine to guinea for testing. according to a xinhua report, it is the only officially authorized and approved ebola vaccine for clinical use to date. works derived from the ebola crisis main article: cultural effects of the ebola crisis "white ebola", a political song by mr. monrovia, ag da profit and daddy cool, centered on the general mistrust of foreigners. "ebola in town", a dance tune by a group of west african rappers, d-12, shadow and kuzzy of 2 kings, warns people of the dangers of the ebola virus and explaining how to react. senegalese rapper xuman parodied rihanna's "umbrella" in "ebola est là" (ebola is here). the song's lyrics warn locals that, "the disease is among our neighbours, liberians and guineans." "africa stop ebola", featuring contributions from malian, guinean, ivorian, congolese and senegalese artists was recorded to raise awareness of ebola and offers info on how people can protect themselves from the disease. the song is sung in several of the local languages. there are a number of ebola-themed jokes circulating in west africa.