Hope for HIV control in southern Africa: The continued quest for a vaccine

Major Scientific Hurdles in HIV Vaccine Development: Historical Perspective and Future Directions

Following the discovery of HIV as a causative agent of AIDS, the expectation was to rapidly develop a vaccine; but thirty years later, we still do not have a licensed vaccine. Progress has been hindered by the extensive genetic variability of HIV and our limited understanding of immune responses required to protect against HIV acquisition. Nonetheless, valuable knowledge accrued from numerous basic and translational science research studies and vaccine trials has provided insight into the structural biology of the virus, immunogen design and novel vaccine delivery systems that will likely constitute an effective vaccine. Furthermore, stakeholders now appreciate the daunting scientific challenges of developing an effective HIV vaccine, hence the increased advocacy for collaborative efforts among academic research scientists, governments, pharmaceutical industry, philanthropy, and regulatory entities. In this review, we highlight the history of HIV vaccine development efforts, highlighting major challenges and future directions.

HIV Vaccine Preparedness among Men Who Have Sex with Men in Taiwan: Sociocultural and Behavioral Factors

In Taiwan, men who have sex with men (MSM) are at disproportionate risk of HIV infection. We examined awareness and acceptability of future HIV vaccines. From July to August 2014, we conducted a cross-sectional survey with MSM recruited through community-based organizations (CBOs) in 2 cities. Among 200 participants (mean age, 27.6 years), half reported multiple partners and one-third condomless anal sex (past 3 months); 12% were HIV-positive. Traditional Chinese medicine (TCM) use was reported by 42.7%. Over two-thirds (69.0%) were aware of HIV vaccine research, but less than half (43.8%) would accept an HIV vaccine if available. In multivariable analysis, higher educational attainment, >5 sex partners, and TCM use were positively associated with HIV vaccine awareness. Culturally informed HIV vaccine preparedness in Taiwan may be supported by a complementary approach to TCM and HIV prevention technologies, tailoring information for MSM with lower education and targeting those at high risk through gay-identified CBOs.

HIV drug resistance in patients in China's national HIV treatment programme who have been on first-line ART for at least 9 months

BACKGROUND

The aim of this study was to assess trends in drug resistance and associated clinical and programmatic factors at a national level during the rapid scale up of ART.

METHODS

Logistic regression was used to identify the factors associated with HIVDR. Variables associated with drug resistance in multivariable logistic regression were included in the Cochran-Armitage test for trend.

RESULTS

A total of 11,976 patients were enrolled in the study. The prevalence of HIVDR among patients who received ART for 9-24 months during 2003-2008, 2009-2012, and 2013-2015 significantly decreased (15.5%, 6.3%, and 2.3%, respectively, P < 0.01). With respect to the class of antiretroviral, there were substantial increases in resistance to both non-nucleoside reverse transcriptase inhibitors (NNRTIs) and nucleoside reverse transcriptase inhibitors (NRTIs) (2003-2008, 2009-2012, and 2013-2015: 49.7%, 58.9%, and 73.0%, respectively, P < 0.01). The prevalence of DR to protease inhibitors (PIs) was low, which supported their continued use as second-line therapy in China.

CONCLUSIONS

Our results provide evidence for the effectiveness of China's "Treat All" approach to guide policy makers to improve training for healthcare providers and education on ART adherence among patients.

Synthesis of an Undecasaccharide Featuring an Oligomannosidic Heptasaccharide and a Bacterial Kdo-lipid A Backbone for Eliciting Neutralizing Antibodies to Mammalian Oligomannose on the HIV-1 Envelope Spike

Lipooligosaccharides (LOS) from the bacterium Rhizobium radiobacter Rv3 are structurally related to antigenic mammalian oligomannoses on the HIV-1 envelope glycoprotein spike that are targets for broadly neutralizing antibodies. Here, we prepared a hybrid structure of viral and bacterial epitopes as part of a vaccine design strategy to elicit oligomannose-specific HIV-neutralizing antibodies using glycoconjugates based on the Rv3 LOS structure. Starting from a Kdo₂GlcNAc₂ tetrasaccharide precursor, a central orthogonally protected mannose trichloroacetimidate donor was coupled to OH-5 of the innermost Kdo residue. To assemble larger glycans, the N-acetylamino groups of the glucosamine units were converted to imides to prevent formation of unwanted imidate byproducts. Blockwise coupling of the pentasaccharide acceptor with an α-(1→2)-linked mannotriosyl trichloroacetimidate donor introduced the D1-arm fragment. Glycosylation of O-6 of the central branching mannose with an α-(1→2)-α-(1→6)-linked mannotriosyl trichloroacetimidate donor unit then furnished the undecasaccharide harboring a D3-arm extension. Global deprotection yielded the 3-aminopropyl ligand, which was activated as an isothiocyanate or adipic acid succinimidoyl ester and conjugated to CRM₁₉₇. However, representative oligomannose-specific HIV-neutralizing antibodies bound the undecasaccharide conjugates poorly. Possible reasons for this outcome are discussed herein along with paths for improvement.

Setting targets for HIV/AIDS-What lessons can be learned from other disease control programmes?

In a Collection Review, Richard Hayes and colleagues discuss metrics for assessing progress in control of the HIV/AIDS epidemic in the context of prior disease control programmes.

'Why would you promote something that is less percent safer than a condom?': Perspectives on partially effective HIV prevention technologies among key populations in South Africa

New biomedical prevention technologies (NPTs) for HIV, including oral Pre-Exposure Prophylaxis, and vaginal and rectal microbicides and HIV vaccines in development, may contribute substantially to controlling the HIV epidemic. However, their effectiveness is contingent on product acceptability and adherence. We explored perceptions and understanding of partially effective NPTs with key populations in South African townships. From October 2013 to February 2014, we conducted six focus groups and 18 individual interviews with Xhosa-speaking adolescents (n = 14), adult men who have sex with men (MSM) (n = 15), and adult heterosexual men (n = 9) and women (n = 10), and eight key informant (KI) interviews with healthcare workers. Interviews/focus groups were transcribed and reviewed using a thematic approach and framework analysis. Overall, participants and KIs indicated scepticism about NPTs that were not 100% efficacious. Some participants equated not being 100% effective with not being completely safe, and thus not appropriate for dissemination. KIs expressed concerns that promoting partially effective NPTs would encourage substitution of a more effective with a less effective method or encourage risk compensation. Educational and social marketing interventions that address the benefits and appropriate use of partially effective NPTs, including education and support tailored for frontline service providers, are needed to prepare for successful NPT implementation in South Africa.

Racial differences in willingness to participate in HIV prevention clinical trials among university students in KwaZulu-Natal, South Africa

Students, especially women, are in the highest HIV incidence group in Sub-Saharan Africa. Willingness to participate is a crucial element in recruitment of participants for clinical trials, including HIV prevention trials. There is increasing incidence of HIV among university students, highlighting the importance of evaluating their willingness to participate in prevention trials. Assessment of willingness to participate assists in determining community preparedness for trials. This cross-sectional study aimed to evaluate willingness to participate and explore racial differences and factors associated with willingness to participate in HIV prevention research. The Clinical Research Involvement Scale and demographic questionnaire were administered online to university students aged 18–45 years at the University of KwaZulu-Natal in South Africa. The instruments evaluated associations between willingness to participate and age, gender, relationship status, parity, religion, education, student and employment status, and access to private health care. This study enrolled 636 participants, of which 509 records were analysable. Most students were willing to participate in HIV prevention research irrespective of race. However, Black students expressed greater intention to participate compared to White and Indian students. Racial differences in factors that affect intentions to participate were differences in risk perception and seeking access to better quality health care. The Clinical Research Involvement Scale is a reliable instrument in this population. Validity improved with removal of factors, motivation to comply, and outcome evaluations. These findings may not be generalizable to other student populations in Southern Africa.