Since a large proportion of our observed cases of tropism switches occurred during periods of detectable viremia, the last tropism test before suppression could be more ideal than a pre-HAART tropism test in predicting tropism switch after viral rebound. Furthermore, our ����deep���� sequencing results reinforce the increased sensitivity of ����deep���� sequencing assay as a prediction tool for viral tropism. These results also suggest that pre-HAART plasma RNA ����deep���� sequencing tropism results, reported either as the percentage non- R5 prevalence or dichotomized as R5/non-R5, could serve as yet another complementary test in addition to DNA tropism predictions for patients with undetectable viremia. Future studies should examine if pre-HAART or pre-suppression RNA R5 tropism is a predictor of clinical outcome in patients who switched into maraviroc-containing regimens during viral suppression. Enterovirus 71 virus infection has recently caused outbreaks of hand-foot-and-mouth disease associated with severe neurological disease in young children and has become a serious public health problem in the Asia-Pacific region EV71 virus is a non-enveloped, single positive-stranded RNA virus of the family Picornaviridae with a VK3-OCH3 genome size of approximately 7.4 kb. The EV71 virus is a pentameric icosahedral particle consisting of 60 copies of the VP1, VP2, VP3 and VP4 capsid proteins. Although the host receptors for EV71 virus had been identified, there is no effective antiviral agent to combat EV71 infection. An effective vaccine is still the best strategy to control and prevent the disease. Experimental EV71 vaccines have included live-attenuated virus, formaldehyde-inactivated virions, virus-like particles, VP1 recombinant protein, VP1 DNA vaccine, VP1 peptide-based vaccine, bacterial or viral vectors expressing VP1, and a Vero cell-adapted live attenuated virus. In previous murine immunogenicity studies, the formalin-inactivated EV71 virus produced from Vero cells DMPQ dihydrochloride elicited a more effective immune response than recombinant VP1 protein or DNA vector vaccines.