This challenge has been particularly difficult because of the nature of the virus, particularly its ability to integrate itself into the genome of host cells, to readily mutate, and to conceal that part of its outer coat that would induce protective antibodies.
Este desafío ha sido particularmente difícil debido a la naturaleza del virus, especialmente su capacidad para integrarse al genoma de las células infectadas, mutar rápidamente y ocultar la parte de su cubierta exterior que provocaría anticuerpos protectores.