科学家已经知道动物细胞不会感染艾滋病病毒，而某些吸毒者或是同性恋者，常与艾滋病患者接触却也没有受到感染。这表明，另有其它因子在艾滋病的感染中发挥重要的作用。 科学家进一步的研究表明，那些幸免于难的极少数人，得益于自身体内ＣＣＲ５基因缺失了３２个碱基，使他们 Scientists already know that animal cells are not infected with HIV, and that some drug users or homosexuals are often exposed to AIDS but are not infected. This shows that there are other factors that play an important role in the AIDS epidemic. Further research by scientists shows that those few survivors benefit from the loss of 32 bases in their own CCR5 genes,