A measles IgM rapid diagnostic test to address challenges with national measles surveillance and response in Malaysia

INTRODUCTION

A lateral flow rapid diagnostic test (RDT) enables detection of measles specific immunoglobulin M (IgM) antibody in serum, capillary blood, and oral fluid with accuracy consistent with enzyme immunoassay (EIA). The objectives of the study were: 1) to assess measles RDT inter-reader agreement between two clinic staff; 2) to assess the sensitivity and specificity of the measles RDT relative to standard surveillance testing in a low transmission setting; 3) to evaluate the knowledge, attitudes, and practices of staff in clinics using the RDT; and 4) to assess the impact of RDT testing on the measles public health response in Malaysia.

MATERIALS AND METHODS

The clinic-based prospective evaluation included all suspected measles cases captured by routine measles surveillance at 34 purposely selected clinics in 15 health districts in Malaysia between September 2019 and June 2020, following day-long regional trainings on RDT use. Following informed consent, four specimens were collected from each suspected case, including those routinely collected for standard surveillance [serum for EIA and throat swabs for quantitative reverse transcriptase polymerase chain reaction (RT-qPCR)] together with capillary blood and oral fluid tested with RDTs during the study. RDT impact was evaluated by comparing the rapidity of measles public health response between the pre-RDT implementation (December 2018 to August 2019) and RDT implementation periods (September 2019 to June 2020). To assess knowledge, attitudes, and practices of RDT use, staff involved in the public health management of measles at the selected sites were surveyed.

RESULTS

Among the 436 suspect cases, agreement of direct visual readings of measles RDT devices between two health clinic staff was 99% for capillary blood (k = 0.94) and 97% for oral fluid (k = 0.90) specimens. Of the total, 45 (10%) were positive by measles IgM EIA (n = 44, including five also positive by RT-qPCR) or RT-qPCR only (n = 1), and 38 were positive by RDT (using either capillary blood or oral fluid). Using measles IgM EIA or RT-qPCR as reference, RDT sensitivity using capillary blood was 43% (95% CI: 30%-58%) and specificity was 98% (95% CI: 96%-99%); using oral fluid, sensitivity (26%, 95% CI: 15%-40%) and specificity (97%, 95% CI: 94%-98%) were lower. Nine months after training, RDT knowledge was high among staff involved with the public health management of measles (average quiz score of 80%) and was highest among those who received formal training (88%), followed by those trained during supervisory visits (83%). During the RDT implementation period, the number of days from case confirmation until initiation of public response decreased by about 5 days.

CONCLUSION

The measles IgM RDT shows >95% inter-reader agreement, high retention of RDT knowledge, and a more rapid public health response. However, despite ≥95% RDT specificity using capillary blood or oral fluid, RDT sensitivity was <45%. Higher-powered studies using highly specific IgM assays and systematic RT-qPCR for case confirmation are needed to establish the role of RDT in measles elimination settings.

Sustaining essential health services in Lao PDR in the context of donor transition and COVID-19

Lao People's Democratic Republic (Lao PDR) aims at graduating from least developed country status by 2026 and must increase the level of domestic financing for health. This paper examines how the government has prepared for the decline of external assistance and how donors have applied their transition approaches. Adapting a World Health Organization (WHO) framework, reflections and lessons were generated based on literature review, informal and formal consultations and focus group discussions with the Lao PDR government and development partners including budget impact discussion. The government has taken three approaches to transition from external to domestic funding: mobilizing domestic resources, increasing efficiency across programs and prioritization with a focus on strengthening primary health care (PHC). The government has increased gradually domestic government health expenditures as a share of the government expenditure from 2.6% in 2013 to 4.9% in 2019. The Ministry of Health has made efforts to design and roll out integrated service delivery of maternal, newborn, child, and adolescent health services, immunization and nutrition; integrated 13 information systems of key health programs into one single District Health Information Software 2; and prioritized PHC, which has led to shifting donors towards supporting PHC. Donors have revisited their aid policies designed to improve sustainability and ownership of the government. However, the government faces challenges in improving cross-programmatic efficiency at the operational level and in further increasing the health budget due to the economic crisis aggravated during Coronavirus disease 2019 (COVID-19). Working to implement donor transition strategies under the current economic situation and country challenges, calls into question the criteria used to evaluate transition. This criterion needs to include more appropriate indicators other than gross national income per capita, which does not reflect a country's readiness and capacity of the health system. There should be a more country-tailored strategy and support for considering the context and system-wide readiness during donor transition.

Concurrent outbreaks of circulating vaccine-derived poliovirus types 1 and 2 affecting the Republic of the Philippines and Malaysia, 2019-2021

Concurrent outbreaks of circulating vaccine-derived poliovirus serotypes 1 and 2 (cVDPV1, cVDPV2) were confirmed in the Republic of the Philippines in September 2019 and were subsequently confirmed in Malaysia by early 2020. There is continuous population subgroup movement in specific geographies between the two countries. Outbreak response efforts focused on sequential supplemental immunization activities with monovalent Sabin strain oral poliovirus vaccine type 2 (mOPV2) and bivalent oral poliovirus vaccines (bOPV, containing Sabin strain types 1 and 3) as well as activities to enhance poliovirus surveillance sensitivity to detect virus circulation. A total of six cVDPV1 cases, 13 cVDPV2 cases, and one immunodeficiency-associated vaccine-derived poliovirus type 2 case were detected, and there were 35 cVDPV1 and 31 cVDPV2 isolates from environmental surveillance sewage collection sites. No further cVDPV1 or cVDPV2 have been detected in either country since March 2020. Response efforts in both countries encountered challenges, particularly those caused by the global COVID-19 pandemic. Important lessons were identified and could be useful for other countries that experience outbreaks of concurrent cVDPV serotypes.

Feasibility, benefits, and cost-effectiveness of adding universal hepatitis B and syphilis testing to routine antenatal care services in Thai Nguyen province, Vietnam

Pregnant women in Vietnam have a high prevalence of hepatitis B virus (HBV) and low prevalence of human immunodeficiency virus (HIV) and syphilis. This study aims to assess the feasibility and benefit of universal testing for HIV, HBV and syphilis in antenatal care (ANC) services. A pilot project was conducted in the Thai Nguyen province of Vietnam between 2012 and 2014. HIV, HBV and syphilis testing were offered to pregnant women. Interventions to eliminate mother-to child-transmission (MTCT) of the three pathogens were provided to infected mothers and their infants. Descriptive analysis was conducted, and the number of infections averted from integrating hepatitis B tests into ANC was estimated. Testing coverage for HIV, HBV and syphilis for the cohort of pregnant women during the pilot project was 98%. Prevalence of HIV, HBV and syphilis infections in this cohort was 0.14%, 7.8%, and 0.03%, respectively. No infant was infected with HIV or syphilis, while HBV infection was diagnosed in 27 infants (13.9%). An estimated 23 mother to child HBV infections were prevented by integrated interventions. The triple prevention of mother-to-child transmission of HIV, HBV and syphilis is feasible. Investment in the expansion of the integrated approach is required to achieve the goal of eliminating MTCT.

High proportion of asymptomatic and presymptomatic COVID-19 infections in air passengers to Brunei

We report early findings from COVID-19 cases in Brunei suggesting a remarkably high proportion of asymptomatic (12%) and presymptomatic (30%) cases. This proportion was even higher in imported cases. These have implications for measures to prevent onward local transmission and should prompt reconsideration of current testing protocols and safe de-escalation of social distancing measures.

Integrated approach for triple elimination of mother-to-child transmission of HIV, hepatitis B and syphilis is highly effective and cost-effective: an economic evaluation

BACKGROUND

The Regional Framework for Triple Elimination of Mother-to-Child Transmission (EMTCT) of HIV, Hepatitis B (HBV) and Syphilis in Asia and the Pacific 2018-30 was endorsed by the Regional Committee of WHO Western Pacific in October 2017, proposing an integrated and coordinated approach to achieve elimination in an efficient, coordinated and sustainable manner. This study aims to assess the population impacts and cost-effectiveness of this integrated approach in the Cambodian context.

METHODS

Based on existing frameworks for the EMTCT for each individual infection, an integrated framework that combines infection prevention procedures with routine antenatal care was constructed. Using decision tree analyses, population impacts, cost-effectiveness and the potential reduction in required resources of the integrated approach as a result of resource pooling and improvements in service coverage and coordination, were evaluated. The tool was assessed using simulated epidemiological data from Cambodia.

RESULTS

The current prevention programme for 370,000 Cambodian pregnant women was estimated at USD$2.3 ($2.0-$2.5) million per year, including the duration of pregnancy and up to 18 months after delivery. A model estimate of current MTCT rates in Cambodia was 6.6% (6.2-7.1%) for HIV, 14.1% (13.1-15.2%) for HBV and 9.4% (9.0-9.8%) for syphilis. Integrating HIV and syphilis prevention into the existing antenatal care framework will reduce the total time required to provide this integrated care by 19% for health care workers and by 32% for pregnant women, resulting in a net saving of $380,000 per year for the EMTCT programme. This integrated approach reduces HIV and HBV MTCT to 6.1% (5.7-6.5%) and 13.0% (12.1-14.0%), respectively, and substantially reduces syphilis MCTC to 4.6% (4.3-5.0%). Further introduction of either antiviral treatment for pregnant women with high viral load of HBV, or hepatitis B immunoglobulin (HBIG) to exposed newborns, will increase the total cost of EMTCT to $4.4 ($3.6-$5.2) million and $3.3 ($2.7-$4.0) million per year, respectively, but substantially reduce HBV MTCT to 3.5% (3.2-3.8%) and 5.0% (4.6-5.5%), respectively. Combining both antiviral and HBIG treatments will further reduce HBV MTCT to 3.4% (3.1-3.7%) at an increased total cost of EMTCT of $4.5 ($3.7-$5.4) million per year. All these HBV intervention scenarios are highly cost-effective ($64-$114 per disability-adjusted life years averted) when the life benefits of these prevention measures are considered.

CONCLUSIONS

The integrated approach, using antenatal, perinatal and postnatal care as a platform in Cambodia for triple EMTCT of HIV, HBV and syphilis, is highly cost-effective and efficient.

Opportunities and barriers for providing HIV testing through community health centers in mainland China: a nationwide cross-sectional survey

Background

Primary care may be an avenue to increase coverage of HIV testing but it is unclear what challenges primary healthcare professionals in low- and middle-income countries face. We describe the HIV testing practices in community health centres (CHCs) and explore the staff’s attitude towards further development of HIV testing services at the primary care level in China.

Methods

We conducted a national, cross-sectional survey using a stratified random sample of CHCs in 20 cities in 2015. Questionnaires were completed by primary care doctors and nurses in CHCs, and included questions regarding their demographics, clinical experience and their views on the facilitators and barriers to offering HIV testing in their CHC. Multivariate logistic regression was conducted to examine the association between staff who would offer HIV testing and their sociodemographic characteristics.

Results

A total of 3580 staff from 158 CHCs participated. Despite the majority (81%) agreeing that HIV testing was an important part of healthcare, only 25% would provide HIV testing when requested by a patient. The majority (71%) were concerned about reimbursement, and half (47%) cited lack of training as a major barrier. Almost half (44%) believed that treating people belonging to high-risk populations would scare other patients away, and 6% openly expressed their dislike of people belonging to high-risk populations. Staff who would offer HIV testing were younger (adjusted odds ratio (aOR) 0.97 per year increase in age, 95% confidence interval (CI):0.97–0.98); trained as a doctor compared to a nurse (aOR 1.79, 95%CI:1.46–2.15); held a bachelor degree or above (aOR 1.34, 95%CI:1.11–1.62); and had previous HIV training (aOR 1.55, 95%CI:1.27–1.89).

Conclusions

Improving HIV training of CHC staff, including addressing stigmatizing attitudes, and improving financial reimbursement may help increase HIV testing coverage in China.

Couples HIV testing and immediate antiretroviral therapy for serodiscordant HIV-positive partners: Translating evidence into programme in Vietnam

Injection drug use and heterosexual transmission from male key populations to their female partners have been the dominant modes of HIV transmission in Vietnam. A demonstration project was conducted to offer immediate antiretroviral therapy (ART) (regardless of CD4 cell count) to HIV-seropositive partners in serodiscordant couples. During March–December 2013, couples HIV testing and counselling (HTC) and immediate ART were offered in two drug use-affected provinces. Of 256 couples receiving couples HTC, 146 (57%) were serodiscordant; 134 (92%) seropositive partners initiated ART irrespective of CD4 cell count. Of these, 86% were male; 57% reported ever using illicit drugs; median CD4 cell count before ART initiation was 374 cells/mm3. Consistent condom use was reported by 58, 70 and 71% among HIV-positive partners at months 0, 3 and 12. At 12 months after ART initiation, 119 (89%) HIV-positive partners were retained in care; 96 (95% of those tested) achieved viral suppression (<1000 copies/ml). Uptake of immediate ART and viral suppression among those initiating ART were high, paving the way for ART regardless of CD4 cell count as national policy in Vietnam.

Systematic review and survey of Neisseria gonorrhoeae ceftriaxone and azithromycin susceptibility data in the Asia Pacific, 2011 to 2016

Background

Antimicrobial resistance in Neisseria gonorrhoeae is a global concern, with the ongoing emergence of ceftriaxone and azithromycin resistance threatening current treatment paradigms. To monitor the emergence of antimicrobial resistance in N. gonorrhoeae, the World Health Organization (WHO) Gonococcal Antimicrobial Surveillance Programme (GASP) has operated in the Western Pacific and South East Asian regions since 1992. The true burden of antimicrobial resistance remains unknown. In response, the objective of this study was to survey ceftriaxone and azithromycin susceptibility in N. gonorrhoeae across the western Pacific and south-east Asia, and interlink this data with systematically reviewed reports of ceftriaxone and azithromycin resistance.

Methods and findings

The WHO Collaborating Centre for Sexually Transmitted Infections and Antimicrobial Resistance, Sydney, coordinated annual surveys of gonococcal susceptibilities with participating laboratories, and additionally undertook a systematic review of reports detailing gonococcal ceftriaxone and azithromycin susceptibility data for locations geographically in the Asia Pacific from 2011 to 2016. It was found that surveillance of gonococcal antimicrobial resistance remains limited in the Asia Pacific, with weaker surveillance of azithromycin versus ceftriaxone. Ninety-three published reports were identified (including national reports) which documented susceptibility data for ceftriaxone and azithromycin. GASP survey data was available for 21 countries, territories or areas, and suggested MICs are increasing for ceftriaxone and azithromycin. Between 2011 and 2016, the percentage of locations reporting >5% of gonococcal isolates with MICs to ceftriaxone meeting WHO’s definition of decreased susceptibility (MIC ≥ 0.125 mg/L) increased from 14.3% to 35.3% and the percentage of locations reporting >5% of gonococcal isolates with azithromycin resistance (MIC ≥ 1 mg/L) increased from 14.3% to 38.9%. Published reports were available for several countries that did not provide GASP surveillance responses for ceftriaxone (n = 5) and azithromycin (n = 3) respectively. Over the study period, there was a 183% increase in the number of countries providing surveillance data for GASP for both ceftriaxone and azithromycin, and a 30.6% increase in ceftriaxone MIC testing across the Asia Pacific facilitated by this project.

Conclusion

This study provides the first comprehensive illustration of increasing MICs to ceftriaxone in the Asia Pacific. The survey and literature review additionally detail increasing resistance to azithromycin. Further surveillance system strengthening is required to monitor these trends in order to address and curb gonococcal AMR in the region.

Improving the hepatitis cascade: assessing hepatitis testing and its management in primary health care in China

OBJECTIVE

The study aimed to decentralize hepatitis testing and management services to primary care in China.

METHODS

A nationwide representative provider survey amongst community health centres (CHCs) using randomized stratified sampling methods was conducted between September and December 2015. One hundred and eighty CHCs and frontline primary care practitioners from 20 cities across three administrative regions of Western, Central and Eastern China were invited to participate.

RESULTS

One hundred and forty-nine clinicians-in-charge (79%), 1734 doctors and 1846 nurses participated (86%). Majority of CHCs (80%, 95% CI: 74-87) offered hepatitis B testing, but just over half (55%, 95% CI: 46-65) offered hepatitis C testing. The majority of doctors (87%) and nurses (85%) felt that there were benefits for providing hepatitis testing at CHCs. The major barriers for not offering hepatitis testing were lack of training (54%) and financial support (23%). Multivariate analysis showed that the major determinants for CHCs to offer hepatitis B and C testing were the number of nurses (AOR 1.1) and written policies for hepatitis B diagnosis (AOR 12.7-27.1), and for hepatitis B the availability of reproductive health service.

CONCLUSIONS

Primary care providers in China could play a pivotal role in screening, diagnosing and treating millions of people with chronic hepatitis B and C in China.

Prevalence of hepatitis C virus infection among key populations in China: A systematic review

BACKGROUND AND AIM

Chronic hepatitis C is a major global health challenge. China has the world's largest burden of hepatitis C and related liver disease, with several groups having an increased risk of acquiring hepatitis C virus (HCV) infection. We undertook a systematic review in Chinese and English literature to determine the seroprevalence of anti-HCV among men who have sex with men (MSM), sex workers, people who use drugs (PWUD) and migrant workers in China.

METHODS

We searched three Chinese databases (CNKI, Wanfang and Chongqing VIP Information) and four English databases (Pubmed, EMBASE, Global Health and CINAHL) for studies published between 2010 and 2015. Included were 89 studies for MSM, 112 for sex workers, 11 for migrant workers, 94 for people who inject drugs (PWID) and 67 for non-injectors. Random-effect models pooled estimates of anti-HCV seroprevalence in each population and a meta-regression model examined the relationship between anti-HCV seroprevalence and injecting drug use.

RESULTS

The overall pooled seroprevalence of anti-HCV among MSM was 0.67% (CI 95 0.51-0.86); for sex workers 0.65% (CI 95 0.53-0.77); for migrant workers 0.48 (CI 95 0.20-0.85); for IDUs 72.41% (CI 95 68.71-75.97); among non-injectors 25.07% (CI 95 21.51%-28.80%). Our meta-regression model predicted that the seroprevalence of anti-HCV among PWID increased by 8.6% for each 10% increase seroprevalence of reporting ever having injected drugs.

CONCLUSIONS

Overall, seroprevalence of HCV infection is high among PWUD, especially those who inject. Lower HCV seroprevalence (<1%) was found among MSM, sex workers and migrant workers. Our estimates for IDU seroprevalence are higher than that from the national surveillance system, though estimates for other at-risk populations are similar.

Chronic hepatitis B virus infection

Chronic hepatitis B virus infection is a global public health threat that causes considerable liver-related morbidity and mortality. It is acquired at birth or later via person-to-person transmission. Vaccination effectively prevents infection and chronic hepatitis B virus carriage. In chronically infected patients, an elevated serum hepatitis B virus DNA concentration is the main risk factor for disease progression, although there are other clinical and viral parameters that influence disease outcomes. In addition to liver biochemistry, virological markers, and abdominal ultrasonography, non-invasive assessment of liver fibrosis is emerging as an important assessment modality. Long-term nucleos(t)ide-analogue therapy is safe and well tolerated, achieves potent viral suppression, and reduces the incidence of liver-related complications. However, a need to optimise management remains. Promising novel therapies are at the developmental stage. With current vaccines, therapies, and an emphasis on improving linkage to care, WHO's goal of eliminating hepatitis B virus as a global health threat by 2030 is achievable.

Challenges and emerging opportunities for the HIV prevention, treatment and care cascade in men who have sex with men in Asia Pacific

In Asia Pacific, most countries have expanded HIV treatment guidelines to include all those with HIV infection and adopted antiretroviral treatment for prevention (TFP) as a blanket strategy for HIV control. Although the overall epidemic development associated with this focus is positive, the HIV epidemic in men who have sex with men (MSM) is continuing unperturbed without any signs of decline or reversal. This raises doubt about whether TFP as a blanket HIV prevention policy is the right approach. This paper reviews currently available biomedical HIV prevention strategies, national HIV prevention policies and guidelines from selected countries and published data on the HIV cascade in MSM. No evidence for efficacy of TFP in protecting MSM from HIV infection was found. The rationale for this approach is based on assumptions about biological plausibility and external validity of latency-based efficacy found in heterosexual couples. This is different from the route and timing of HIV transmission in MSM. New HIV infections in MSM principally occur in chains of acutely HIV-infected highly sexually active young men, in whom acquisition and transmission are correlated in space and time. By the time TFP renders its effects, most new HIV infections in MSM will have already occurred. On a global level, less than 6% of all reports regarding the HIV care cascade from 1990 to 2016 included MSM, and only 2.3% concerned MSM in low/middle-income countries. Only one report originated from Asia Pacific. Generally, HIV cascade data in MSM show a sobering picture of TFP in engaging and retaining MSM along the continuum. Widening the cascade with a preventive extension, including pre-exposure prophylaxis, the first proven efficacious and only biomedical HIV prevention strategy in MSM, will be instrumental in achieving HIV epidemic control in this group.

PrEP implementation in the Asia-Pacific region: opportunities, implementation and barriers

INTRODUCTION

HIV epidemics in the Asia-Pacific region are concentrated among men who have sex with men (MSM) and other key populations. Pre-exposure prophylaxis (PrEP) is an effective HIV prevention intervention and could be a potential game changer in the region. We discuss the progress towards PrEP implementation in the Asia-Pacific region, including opportunities and barriers.

DISCUSSION

Awareness about PrEP in the Asia-Pacific is still low and so are its levels of use. A high proportion of MSM who are aware of PrEP are willing to use it. Key PrEP implementation barriers include poor knowledge about PrEP, limited access to PrEP, weak or non-existent HIV prevention programmes for MSM and other key populations, high cost of PrEP, stigma and discrimination against key populations and restrictive laws in some countries. Only several clinical trials, demonstration projects and a few larger-scale implementation studies have been implemented so far in Thailand and Australia. However, novel approaches to PrEP implementation have emerged: researcher-, facility- and community-led models of care, with PrEP services for fee and for free. The WHO consolidated guidelines on HIV testing, treatment and prevention call for an expanded access to PrEP worldwide and have provided guidance on PrEP implementation in the region. Some countries like Australia have released national PrEP guidelines. There are growing community leadership and consultation processes to initiate PrEP implementation in Asia and the Pacific.

CONCLUSIONS

Countries of the Asia-Pacific region will benefit from adding PrEP to their HIV prevention packages, but for many this is a critical step that requires resourcing. Having an impact on the HIV epidemic requires investment. The next years should see the region transitioning from limited PrEP implementation projects to growing access to PrEP and expansion of HIV prevention programmes.

Interventions to optimise the care continuum for chronic viral hepatitis: a systematic review and meta-analyses

BACKGROUND

Advances in therapy for hepatitis B virus (HBV) and hepatitis C virus (HCV) have ushered in a new era in chronic hepatitis treatment. To maximise the effectiveness of these medicines, individuals must be engaged and retained in care. We analysed operational interventions to enhance chronic viral hepatitis testing, linkage to care, treatment uptake, adherence, and viral suppression or cure.

METHODS

We did a systematic review of operational interventions, and did meta-analyses for sufficiently comparable data. We searched PubMed, Embase, WHO library, International Clinical Trials Registry Platform, PsycINFO, and CINAHL for randomised controlled trials and controlled non-randomised studies that examined operational interventions along the chronic viral hepatitis care continuum, published in English up to Dec 31, 2014. We included non-pharmaceutical intervention studies with primary or secondary outcomes of testing, linkage to care, treatment uptake, treatment adherence, treatment completion, treatment outcome, or viral endpoints. We excluded dissertations and studies of children only. Data were extracted by two independent reviewers, with disagreements resolved by a third reviewer. Studies were assessed for bias. Data from similar interventions were pooled and quality of evidence was assessed using GRADE. This study was registered in PROSPERO (42014015094).

FINDINGS

We identified 7583 unduplicated studies, and included 56 studies that reported outcomes along the care continuum (41 for HCV and 18 for HBV). All studies except one were from high-income countries. Lay health worker HBV test promotion interventions increased HBV testing rates (relative risk [RR] 2·68, 95% CI 1·82-3·93). Clinician reminders to prompt HCV testing during clinical visits increased HCV testing rates (3·70, 1·81-7·57). Nurse-led educational interventions improved HCV treatment completion (1·14, 1·05-1·23) and cure (odds ratio [OR] 1·93, 95% CI 1·44-2·59). Coordinated mental health, substance misuse, and hepatitis treatment services increased HCV treatment uptake (OR 3·03, 1·24-7·37), adherence (RR 1·22, 1·05-1·41), and cure (RR 1·21, 1·07-1·38) compared with usual care.

INTERPRETATION

Several simple, inexpensive operational interventions can substantially improve engagement and retention along the chronic viral hepatitis care continuum. Further operational research to inform scale-up of hepatitis services is needed in low-income and middle-income countries.

FUNDING

World Health Organization and US Fulbright Program.

International AIDS Society global scientific strategy: towards an HIV cure 2016

Antiretroviral therapy is not curative. Given the challenges in providing lifelong therapy to a global population of more than 35 million people living with HIV, there is intense interest in developing a cure for HIV infection. The International AIDS Society convened a group of international experts to develop a scientific strategy for research towards an HIV cure. This Perspective summarizes the group's strategy.

Implications of prioritizing HIV cure: new momentum to overcome old challenges in HIV

Background

Curing HIV is a new strategic priority for several major AIDS organizations. In step with this new priority, HIV cure research and related programs are advancing in low, middle, and high-income country settings. This HIV cure momentum may influence existing HIV programs and research priorities.

Discussion

Despite the early stage of ongoing HIV cure efforts, these changes have directly influenced HIV research funding priorities, pilot programs, and HIV messaging. The building momentum to cure HIV infection may synergize with strategic priorities to better identify adults and infants with very early HIV infection. Although HIV cure represents a new goal, many existing programs and research techniques can be repurposed towards an HIV cure. HIV messages focused on engaging communities towards an HIV cure need to be careful to promote ARV adherence and retention within the HIV continuum of care.

Summary

An increased emphasis within the AIDS field on finding an HIV cure has several important implications. Strengthening connections between HIV cure research and other areas of HIV research may help to catalyze research and facilitate implementation in the future.

HIV Epidemic in Asia: Implications for HIV Vaccine and Other Prevention Trials

An overall decrease of HIV prevalence is now observed in several key Asian countries due to effective prevention programs. The decrease in HIV prevalence and incidence may further improve with the scale-up of combination prevention interventions. The implementation of future prevention trials then faces important challenges. The opportunity to identify heterosexual populations at high risk such as female sex workers may rapidly wane. With unabating HIV epidemics among men who have sex with men (MSM) and transgender (TG) populations, an effective vaccine would likely be the only option to turn the epidemic. It is more likely that efficacy trials will occur among MSM and TG because their higher HIV incidence permits smaller and less costly trials. The constantly evolving patterns of HIV-1 diversity in the region suggest close monitoring of the molecular HIV epidemic in potential target populations for HIV vaccine efficacy trials. CRF01_AE remains predominant in southeast Asian countries and MSM populations in China. This relatively steady pattern is conducive to regional efficacy trials, and as efficacy warrants, to regional licensure. While vaccines inducing nonneutralizing antibodies have promise against HIV acquisition, vaccines designed to induce broadly neutralizing antibodies and cell-mediated immune responses of greater breadth and depth in the mucosal compartments should be considered for testing in MSM and TG. The rationale and design of efficacy trials of combination prevention modalities such as HIV vaccine and preexposure prophylaxis (PrEP) remain hypothetical, require high adherence to PrEP, are more costly, and present new regulatory challenges. The prioritization of prevention interventions should be driven by the HIV epidemic and decided by the country-specific health and regulatory authorities. Modeling the impact and cost-benefit may help this decision process.

The hepatitis C treatment revolution: how to avoid Asia missing out

The Asia-Pacific region bears a high burden of hepatitis C virus (HCV) infections and the largest number of global deaths. Populations most at risk of infection and disease progression include people who inject drugs and those living with HIV. HCV treatment options have rapidly expanded in the past few years through the development of direct-acting antiviral (DAA) medicines, which can cure HCV in over 95% of cases, but are prohibitively expensive. While price is the major barrier to treatment access, voluntary licensing has resulted in limited availability of one DAA (sofosbuvir) through generic manufacturers in India. Regulatory barriers, such as the need for domestic clinical trials, cause further delays in local medicines approvals and access. Intensive advocacy by civil society in combination with mobilisation of global resources for HIV treatment were critical to achieving price reductions in HIV medicines in the early 2000s. While the current global economic situation is less conducive to substantial funding support for HCV treatment, community advocates are building awareness of the growing opportunities for HCV cure. Key immediate steps include the inclusion of DAAs in domestic essential medicines lists, as the World Health Organization has already done for globally, and fast-tracking domestic drug approvals to facilitate government-level price negotiations with originator and generic pharmaceutical companies. Urgent action by a broad range of stakeholders is needed to facilitate access to HCV treatment in order to ensure that the millions of people living with hepatitis C in the Asia-Pacific will not miss out on these life-saving treatments.

Enhancing the benefits of antiretroviral therapy in Vietnam: towards ending AIDS

Vietnam has a concentrated HIV epidemic, with the highest HIV prevalence being observed among people who inject drugs (PWID). Based on its experience scaling-up robust HIV interventions, Vietnam aims to further strengthen its response by harnessing the preventive benefits of antiretroviral therapy (ART). Mathematical modelling suggests that prioritizing key populations for earlier access to ART, combined with other prevention interventions, may have significant impact on the epidemic, cost-effectively reducing new HIV infections and deaths. Pilot studies are being conducted to assess feasibility and acceptability of expansion of HIV testing and counselling (HTC) and early ART among key populations and to demonstrate innovative service delivery models to address challenges in uptake of services across the care cascade. Earlier access of key populations to combination prevention interventions, combined with sustained political commitment and supportive environment for key populations, are essential for maximum impact of ART on the HIV epidemic in Vietnam.

Stakeholder Engagement in HIV Cure Research: Lessons Learned from Other HIV Interventions and the Way Forward

Clinical and basic science advances have raised considerable hope for achieving an HIV cure by accelerating research. This research is dominated primarily by issues about the nature and design of current and future clinical trials. Stakeholder engagement for HIV cure remains in its early stages. Our analysis examines timing and mechanisms of historical stakeholder engagement in other HIV research areas for HIV-uninfected individuals [vaccine development and pre-exposure prophylaxis (PrEP)], and HIV-infected individuals (treatment as prevention, prevention of mother-to-child transmission, and treatment of acute HIV infection) and articulate a plan for HIV cure stakeholder engagement. The experience from HIV vaccine development shows that early engagement of stakeholders helped manage expectations, mitigating the failure of several vaccine trials, while paving the way for subsequent trials. The relatively late engagement of HIV stakeholders in PrEP research may partly explain some of the implementation challenges. The treatment-related stakeholder engagement was strong and community-led from the onset and helped translation from research to implementation. We outline five steps to initiate and sustain stakeholder engagement in HIV cure research and conclude that stakeholder engagement represents a key investment in which stakeholders mutually agree to share knowledge, benefits, and risk of failure. Effective stakeholder engagement prevents misconceptions. As HIV cure research advances from early trials involving subjects with generally favorable prognosis to studies involving greater risk and uncertainty, success may depend on early and deliberate engagement of stakeholders.

Prevention of mother-to-child HIV transmission cascade in China: a systematic review and meta-analysis

INTRODUCTION

The Chinese government has invested US$140 million annually on prevention of mother-to-child transmission (PMTCT) of HIV. This study evaluates the programme by examining the improvements in programme coverage HIV testing and provision of antiviral drugs along the PMTCT cascade.

METHODS

Data for PMTCT cascade indicators were collected through a comprehensive systematic review of published peer-reviewed English and Chinese literature during 2003-2011. Meta-analysis was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

This study included 113 publications. HIV prevalence among pregnant women in China who accessed antenatal care (ANC) remained below 0.1% during the past decade. HIV testing coverage in pregnant women attending ANC and in HIV-exposed infants at 18 months significantly increased from 62.4% (95% CI 4.7% to 98.2%) and 22.1% (16.3% to 32.3%) in 2003 to 90.3% (88.4% to 91.8%) and 82.8% (66.9% to 99.5%) in 2011 respectively, whereas antiretroviral (ARV) prophylaxis uptake increased from 35.2% (12.2% to 47.3%) and 26.9% (24.3% to 28.9%) to 86.2% (53.2% to 97.2%) and 90.3% (85.5% to 93.7%). HIV vertical transmission rate substantially decreased from 31.8% (25.7% to 38.6%) prior to the programme to 2.3% (1.4% to 3.8%) in 2011. During 2003-2011, among 25,312 (23,995-26,644) infants born to HIV-positive mothers who received ARV prophylaxis, 975 (564-1395) were diagnosed with HIV, corresponding to an average transmission rate of 3.9% (3.2% to 4.6%). However, while including transmissions among HIV-positive pregnant women who were lost along the cascade, the average transmission rate during 2003-2011 was 17.4% (15.8% to 19.0%).

CONCLUSIONS

PMTCT programmes have reduced HIV mother-to-child transmission in China. Further improvements in the continuum of care remain essential in realising the full potential of the programme.

HIV self-testing among key populations: an implementation science approach to evaluating self-testing

OBJECTIVES

To review methods for measuring HIV self-testing (HIVST) among key populations, including both conventional approaches and implementation science approaches.

METHODS

We reviewed the literature on evaluating HIVST among key populations.

RESULTS

Simple HIV self-tests have already entered markets in several regions, but metrics required to demonstrate the benefits and costs of HIVST remain simplistic. Conventional measurements of sensitivity, specificity, acceptability, and behavioural preferences must be supplemented with richer implementation science measurement tools and innovative research designs in order to capture data on the following components: how self-testing affects subsequent linkage to confirmatory testing, preventive services and onward steps in the HIV continuum of care; how self-testing can be marketed to reach untested subpopulations; and how self-testing can be sustained based on overarching organisational and financial models. We outline an implementation science research agenda that incorporates these components, drawing from evaluation study designs focused on HIVST and testing in general.

CONCLUSION

HIVST holds great promise for key populations, but must be guided by implementation research to inform programmes and scale up.

Effects of HIV antiretroviral therapy on sexual and injecting risk-taking behavior: a systematic review and meta-analysis

BACKGROUND

Increased global access and use of antiretroviral therapy (ART) for human immunodeficiency virus (HIV) has been postulated to undermine HIV prevention efforts by changing individual risk-taking behavior. This review aims to determine whether ART use is associated with changes in sexual or injecting risk-taking behavior or diagnosis of sexually transmitted infections (STIs).

METHODS

A systematic review and meta-analysis was conducted of HIV-seropositive participants receiving ART compared with no ART use in experimental or observational studies. Primary outcomes included (1) any unprotected sexual intercourse, (2) STI diagnoses, and (3) any unsafe injecting behavior.

RESULTS

Fifty-eight studies met the selection criteria. Fifty-six studies containing 32 857 participants reported unprotected sex; 11 studies containing 16 138 participants reported STI diagnoses; and 4 studies containing 1600 participants reported unsafe injecting behavior. All included studies were observational. Unprotected sex was lower in participants receiving ART than in those not receiving ART (odds ratio [OR], 0.73; 95% confidence interval [CI], .64-.83; P < .001; heterogeneity I(2) = 79%) in both high-income (n = 38) and low-/middle-income country (n = 18) settings, without any evidence of publication bias. STI diagnoses were also lower among individuals on ART (OR, 0.58; 95% CI, .33-1.01; P = .053; I(2) = 92%); however, there was no difference in injecting risk-taking behavior with antiretroviral use (OR, 0.90; 95% CI, .60-1.35; P = .6; I(2) = 0%).

CONCLUSIONS

Despite concerns that use of ART might increase sexual or injecting risk-taking, available research suggests that unprotected sex is reduced among HIV-infected individuals on treatment. The reasons for this are not yet clear, although self-selection and mutually reinforcing effects of HIV treatment and prevention messages among people on ART are likely.

Halting and reversing HIV epidemics in Asia by interrupting transmission in sex work: experience and outcomes from ten countries

HIV epidemics spread rapidly through Asian sex work networks two decades ago under conditions of high vulnerability, low condom use, intact male foreskins and ulcerative STIs. Experiences implementing interventions to prevent transmission in sex work in ten Asian countries were reviewed. All report increasing condom use trends in sex work. In the seven countries where condom use exceeds 80%, surveillance and other data indicate declining HIV trends or low and stable HIV prevalence with declining STI trends. All four countries with national-level HIV declines among sex workers have also documented significant HIV declines in the general population. While all interventions in sex work included outreach, condom programing and STI services, the largest declines were found in countries that implemented structural interventions on a large scale. Thailand and Cambodia, having controlled transmission early, are closest to providing universal access to HIV care, support and treatment and are exploring HIV elimination strategies.

Gonococcal antimicrobial resistance in the Western Pacific Region

OBJECTIVE

To outline the current situation of gonococcal antimicrobial resistance (AMR) in the Western Pacific region and factors that impact on this.

BACKGROUND

The Western Pacific region is densely populated with many living in poverty. There are high rates of infectious diseases, and a disproportionate burden of gonococcal disease. In many countries there is uncontrolled antimicrobial use: these are ideal conditions for the emergence of AMR.

METHODS

Gonococcal AMR in this region has been monitored for more than 20 years. Clinical isolates, predominantly from unselected patients attending sexually transmitted diseases clinics, are tested against a panel of antibiotics. Quality assurance and control strategies are in place.

RESULTS

There is widespread, high level resistance to penicillin and ciprofloxacin. Decreased susceptibility to ceftriaxone (MIC ≥ 0.06 mg/L) is reported in high levels from some countries in the region. Low numbers of isolates tested in some countries reflect capacity for testing, and are suboptimal for surveillance.

CONCLUSION

The raised MIC values to ceftriaxone, and the emergence and spread of ceftriaxone resistant strains regionally is alarming. Sustaining and enhancing surveillance is critical; however obtaining an adequate sample size is a long-standing issue. The implementation of molecular surveillance strategies could provide broader information on the spread and threat of AMR.

Challenges and potential barriers to the uptake of antiretroviral-based prevention in Asia and the Pacific region

Evidence has emerged over the past few years on the effectiveness of antiretroviral-based prevention technologies to prevent (i) HIV transmission while decreasing morbidity and mortality in HIV-infected persons, and (ii) HIV acquisition in HIV-uninfected individuals through pre-exposure prophylaxis (PrEP). Only few of the planned studies on treatment as prevention (TasP) are conducted in Asia. TasP might be more feasible and effective in concentrated rather than in generalised epidemics, as resources for HIV testing and antiretroviral treatment could focus on confined and much smaller populations than in the generalised epidemics observed in sub-Saharan Africa. Several countries such as Cambodia, China, Thailand and Vietnam, are now paving the way to success. Similar challenges arise for both TasP and PrEP. However, the operational issues for PrEP are amplified by the need for frequent retesting and ensuring adherence. This paper describes challenges for the implementation of antiretroviral-based prevention and makes the case that TasP and PrEP implementation research in Asia is much needed to provide insights into the feasibility of these interventions in populations where firm evidence of ‘real world’ effectiveness is still lacking.

Maximizing the impact of HIV prevention efforts: interventions for couples

Despite efforts to increase access to HIV testing and counseling services, population coverage remains low. As a result, many people in sub-Saharan Africa do not know their own HIV status or the status of their sex partner(s). Recent evidence, however, indicates that as many as half of HIV-positive individuals in ongoing sexual relationships have an HIV-negative partner and that a significant proportion of new HIV infections in generalized epidemics occur within serodiscordant couples. Integrating couples HIV testing and counseling (CHTC) into routine clinic- and community-based services can significantly increase the number of couples where the status of both partners is known. Offering couples a set of evidence-based interventions once their HIV status has been determined can significantly reduce HIV incidence within couples and if implemented with sufficient scale and coverage, potentially reduce population-level HIV incidence as well. This article describes these interventions and their potential benefits.

Impact of high-risk sex and focused interventions in heterosexual HIV epidemics: a systematic review of mathematical models

Background

The core-group theory of sexually transmitted infections suggests that targeting prevention to high-risk groups (HRG) could be very effective. We aimed to quantify the contribution of heterosexual HRGs and the potential impact of focused interventions to HIV transmission in the wider community.

Methods

We systematically identified studies published between 1980 and 2011. Studies were included if they used dynamical models of heterosexual HIV transmission, incorporated behavioural heterogeneity in risk, and provided at least one of the following primary estimates in the wider community (a) the population attributable fraction (PAF) of HIV infections due to HRGs, or (b) the number per capita or fraction of HIV infections averted, or change in HIV prevalence/incidence due to focused interventions.

Findings

Of 267 selected articles, 22 were included. Four studies measured the PAF, and 20 studies measured intervention impact across 265 scenarios. In low-prevalence epidemics (≤5% HIV prevalence), the estimated impact of sex-worker interventions in the absence of risk compensation included: 6–100% infections averted; 0.9–6.2 HIV infections averted per 100,000 adults; 11–94% and 4–47% relative reduction in prevalence and incidence respectively. In high-prevalence epidemics (>5% HIV prevalence), sex-worker interventions were estimated to avert 6.8–40% of HIV infections and up to 564 HIV infections per 100,000 adults, and reduce HIV prevalence and incidence by 13–27% and 2–14% respectively. In both types of epidemics, greater heterogeneity in HIV risk was associated with a larger impact on the fraction of HIV infections averted and relative reduction in HIV incidence.

Conclusion

Focused interventions, as estimated by mathematical models, have the potential to reduce HIV transmission in the wider community across low- and high-prevalence regions. However, considerable variability exists in estimated impact, suggesting that a targeted approach to HIV prevention should be tailored to local epidemiological context.

Using GRADE methodology for the development of public health guidelines for the prevention and treatment of HIV and other STIs among men who have sex with men and transgender people

BACKGROUND

The World Health Organization (WHO) Department of HIV/AIDS led the development of public health guidelines for delivering an evidence-based, essential package of interventions for the prevention and treatment of HIV and other sexually transmitted infections (STIs) among men who have sex with men (MSM) and transgender people in the health sector in low- and middle-income countries. The objective of this paper is to review the methodological challenges faced and solutions applied during the development of the guidelines.

METHODS

The development of the guidelines followed the WHO guideline development process, which utilizes the GRADE approach. We identified, categorized and labeled the challenges identified in the guidelines development process and described the solutions through an interactive process of in-person and electronic communication.

RESULTS

We describe how we dealt with the following challenges: (1) heterogeneous and complex interventions; (2) paucity of trial data; (3) selecting outcomes of interest; (4) using indirect evidence; (5) integrating values and preferences; (6) considering resource use; (7) addressing social and legal barriers; (8) wording of recommendations; and (9) developing global guidelines.

CONCLUSION

We were able to successfully apply the GRADE approach for developing recommendations for public health interventions. Applying the general principles of the approach while carefully considering specific challenges can enhance both the process and the outcome of guideline development.

Socio-demographic characteristics and behavioral risk factors of female sex workers in sub-saharan Africa: a systematic review

Sex work remains an important contributor to HIV transmission within early, advanced and regressing epidemics in sub-Saharan Africa, but its social and behavioral underpinnings remain poorly understood, limiting the impact of HIV prevention initiatives. This article systematically reviews the socio-demographics of female sex workers (FSW) in this region, their occupational contexts and key behavioral risk factors for HIV. In total 128 relevant articles were reviewed following a search of Medline, Web of Science and Anthropological Index. FSW commonly have limited economic options, many dependents, marital disruption, and low education. Their vulnerability to HIV, heightened among young women, is inextricably linked to the occupational contexts of their work, characterized most commonly by poverty, endemic violence, criminalization, high mobility and hazardous alcohol use. These, in turn, predict behaviors such as low condom use, anal sex and co-infection with other sexually transmitted infections. Sex work in Africa cannot be viewed in isolation from other HIV-risk behaviors such as multiple concurrent partnerships-there is often much overlap between sexual networks. High turn-over of FSW, with sex work duration typically around 3 years, further heightens risk of HIV acquisition and transmission. Targeted services at sufficiently high coverage, taking into account the behavioral and social vulnerabilities described here, are urgently required to address the disproportionate burden of HIV carried by FSW on the continent.

Harnessing the prevention benefits of antiretroviral therapy to address HIV and tuberculosis

After 30 years we are still struggling to address a devastating HIV pandemic in which over 25 million people have died. In 2010, an estimated 34 million people were living with HIV, around 70% of whom live in sub-Saharan Africa. Furthermore, in 2009 there were an estimated 1.2 million new HIV-associated TB cases, and tuberculosis (TB) accounted for 24% of HIV-related deaths. By the end of 2010, 6.6 million people were taking antiretroviral therapy (ART), around 42% of those in need as defined by the 2010 World Health Organization (WHO) guidelines. Despite this achievement, around 9 million people were eligible and still in need of treatment, and new infections (approximately 2.6 million in 2010 alone) continue to add to the future caseload. This combined with the international fiscal crisis has led to a growing concern regarding weakening of the international commitment to universal access and delivery of the Millennium Development Goals by 2015. The recently launched UNAIDS/WHO Treatment 2.0 platform calls for accelerated simplification of ART, in line with a public health approach, to achieve and sustain universal access to ART, including maximizing the HIV and TB preventive benefit of ART by treating people earlier, in line with WHO 2010 normative guidance. The potential individual and public health prevention benefits of using treatment in the prevention of HIV and TB enhance the value of the universal access pledge from a life-saving initiative, to a strategic investment aimed at ending the HIV epidemic. This review analyzes the gaps and summarizes the evidence regarding ART in the prevention of HIV and TB.

Antiretroviral therapy in prevention of HIV and TB: update on current research efforts

There is considerable scientific evidence supporting the use of antiretroviral therapy (ART) in prevention of human immunodeficiency virus (HIV) and tuberculosis (TB) infections. The complex nature of the HIV and TB prevention responses, resource constraints, remaining questions about cost and feasibility, and the need to use a solid evidence base to make policy decisions, and the implementation challenges to translating trial data to operational settings require a well-organised and coordinated response to research in this area. To this end, we aimed to catalogue the ongoing and planned research activities that evaluate the impact of ART plus other interventions on HIV- and/or TB-related morbidity, mortality, risk behaviour, HIV incidence and transmission. Using a limited search methodology, 50 projects were identified examining ART as prevention, representing 5 regions and 52 countries with a global distribution. There are 24 randomised controlled clinical trials with at least 12 large randomised individual or community cluster trials in resource-constrained settings that are in the planning or early implementation stages. There is considerable heterogeneity between studies in terms of methodology, interventions and geographical location. While the identified studies will undoubtedly advance our understanding of the efficacy and effectiveness of ART for prevention, some key questions may remain unanswered or only partially answered. The large number and wide variety of research projects emphasise the importance of this research issue and clearly demonstrate the potential for synergies, partnerships and coordination across funding agencies.

Male circumcision for prevention of homosexual acquisition of HIV in men

BACKGROUND

Previous systematic reviews found inconsistent effects of male circumcision on HIV acquisition in men who have sex with men (MSM). However, a number of new studies have become available in the three years since the last systematic review.

OBJECTIVES

To assess the effects of male circumcision for preventing HIV acquisition by men through sex with men.

SEARCH STRATEGY

In June 2010 we electronically searched the Cochrane Central Register of Controlled Trials, PubMed, EMBASE, AIDS Education Global Information System, ClinicalTrials.gov, and WHO International Clinical Trials Registry Platform; hand-searched reference lists of relevant articles; and contacted relevant organisations and experts. We updated the search in March 2011.

SELECTION CRITERIA

We looked for randomised controlled trials (RCTs) and observational studies that assessed the effects of male circumcision on HIV acquisition in MSM.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study eligibility and methodological quality, and extracted data. We expressed study results as odds ratios (OR) with 95% confidence intervals (CI), and conducted random-effects meta-analysis.

MAIN RESULTS

We found no completed RCT and included 21 observational studies with 71,693 participants. The only eligible RCT is currently ongoing among MSM in China. The pooled effect estimate for HIV acquisition was not statistically significant (20 studies; 65,784 participants; OR 0.86, 95% CI 0.70 to 1.06) and showed significant heterogeneity (I²=53%). In a subgroup analysis, the results were statistically significant in studies of men reporting an insertive role (7 studies, 3465 participants; OR 0.27, 95% CI 0.17 to 0.44; I²=0%) but not in studies of men reporting a receptive role (3 studies, 1792 participants; OR 1.20, 95% CI 0.63 to 2.29; I² = 0%). There was no significant association between male circumcision and syphilis (8 studies; 34,999 participants: OR 0.96, 95% CI 0.82 to 1.13; I² = 0%), herpes simplex virus 1 (2 studies, 2740 participants; OR 0.90, 95% CI 0.53 to 1.52; I²=0%), or herpes simplex virus 2 (5 studies;10,285 participants; OR 0.86, 95% CI 0.62 to 1.21; I²=0%). The overall GRADE quality of evidence was low. None of the included studies assessed adverse effects associated with male circumcision.

AUTHORS' CONCLUSIONS

Current evidence suggests that male circumcision may be protective among MSM who practice primarily insertive anal sex, but the role of male circumcision overall in the prevention of HIV and other sexually transmitted infections among MSM remains to be determined. Therefore, there is not enough evidence to recommend male circumcision for HIV prevention among MSM at present. Further research should be of high quality and further explore interaction with the predominant sexual role.

Planning for pre-exposure prophylaxis to prevent HIV transmission: challenges and opportunities

There are currently several ongoing or planned trials evaluating the efficacy of pre-exposure prophylaxis (PrEP) as a preventative approach to reducing the transmission of HIV. PrEP may prove ineffective, demonstrate partial efficacy, or show high efficacy and have the potential to reduce HIV infection in a significant way. However, in addition to the trial results, it is important that issues related to delivery, implementation and further research are also discussed. As a part of the ongoing discussion, in June 2009, the Bill & Melinda Gates Foundation sponsored a Planning for PrEP conference with stakeholders to review expected trial results, outline responsible educational approaches, and develop potential delivery and implementation strategies. The conference reinforced the need for continued and sustained dialogue to identify where PrEP implementation may fit best within an integrated HIV prevention package. This paper identifies the key action points that emerged from the Planning for PrEP meeting.

Highly active antiretroviral treatment as prevention of HIV transmission: review of scientific evidence and update

PURPOSE OF REVIEW

An estimated 33 million people are living with HIV and universal access remains a dream for millions of people. By the end of year 2008, four million people were on treatment; however, over five million needed treatment, and in 2007, there were 2.7 million new infections. Without significant improvement in prevention, we are unlikely to meet universal access targets including the growing demand for highly active antiretroviral treatment (HAART). This review examines HAART as a potential tool for preventing HIV transmission.

RECENT FINDINGS

We discuss recent scientific evidence regarding the treatment and prevention gap, importance viral load and HIV transmission, HAART and HIV transmission, when to start, HIV counseling and testing, modeling results and next steps.

SUMMARY

HAART has considerable treatment and prevention benefits and it needs to be considered as a key element of combination prevention. To explore HAART as an effective prevention strategy, we recommend further evaluation of human rights and ethical considerations, clarification of research priorities and exploration of feasibility and acceptability issues.

Highly active antiretroviral treatment for the prevention of HIV transmission

In 2007 an estimated 33 million people were living with HIV; 67% resided in sub-Saharan Africa, with 35% in eight countries alone. In 2007, there were about 1.4 million HIV-positive tuberculosis cases. Globally, approximately 4 million people had been given highly active antiretroviral therapy (HAART) by the end of 2008, but in 2007, an estimated 6.7 million were still in need of HAART and 2.7 million more became infected with HIV.

Although there has been unprecedented investment in confronting HIV/AIDS - the Joint United Nations Programme on HIV/AIDS estimates $13.8 billion was spent in 2008 - a key challenge is how to address the HIV/AIDS epidemic given limited and potentially shrinking resources. Economic disparities may further exacerbate human rights issues and widen the increasingly divergent approaches to HIV prevention, care and treatment.

HIV transmission only occurs from people with HIV, and viral load is the single greatest risk factor for all modes of transmission. HAART can lower viral load to nearly undetectable levels. Prevention of mother to child transmission offers proof of the concept of HAART interrupting transmission, and observational studies and previous modelling work support using HAART for prevention. Although knowing one's HIV status is key for prevention efforts, it is not known with certainty when to start HAART.

Building on previous modelling work, we used an HIV/AIDS epidemic of South African intensity to explore the impact of testing all adults annually and starting persons on HAART immediately after they are diagnosed as HIV positive. This theoretical strategy would reduce annual HIV incidence and mortality to less than one case per 1000 people within 10 years and it would reduce the prevalence of HIV to less than 1% within 50 years. To explore HAART as a prevention strategy, we recommend further discussions to explore human rights and ethical considerations, clarify research priorities and review feasibility and acceptability issues.

Epidemiology of HIV-TB in Asia

Tuberculosis (TB) has, for centuries, continued to remain a public health problem of enormous importance, particularly in the developing world, taking a heavy toll of those at their prime of life. The emergence of human immunodeficiency virus (HIV infection) and its close association with TB poses an even greater challenge to the health systems in general and TB programmes in particular, in African and Asian countries. HIV is considered to be the most potent risk factor for progression to active TB among those infected both with TB and HIV; as a result, TB is the most common life threatening opportunistic infection associated with HIV, and biggest cause of death among patients with acquired immunodeficiency syndrome (AIDS). In areas hard-hit by HIV, TB is increasing, leading to greater case load, thereby overstretching the already fragile health infrastructure. The deadly relationship between HIV and TB, each potentiating the effect of the other, requires a clearly defined strategy taking into consideration the natural history of the co-infection and its progression to clinical TB (and AIDS). It is clear that the only way to fight this is by bringing the two programmes to join forces and work creatively and innovatively. The strategy should include not only preventing HIV through community-based behavioural interventions and limiting progression to clinical TB through the use of isoniazid preventive therapy, but also early diagnosis and treatment of HIV-associated TB and AIDS using DOTS strategy and combination antiretroviral therapy respectively. The strategy probably would not succeed unless both the programmes are first strengthened before attempting to forge collaboration based on mutual strengths and comparative advantages. In addition, mobilizing national and international response, building partnerships and mobilizing resources will help a great deal in mounting an appropriate and effective response to HIV/TB in the Asian context.

Exploring the recognized bio-mimicry materials for gas sensing

This study was undertaken to synthesize peptides that are partially similar to the binding sites of human olfactory receptor protein. First, a putative 3-D model structure of human olfactory receptor protein (P30953) was modeled using a molecular simulation method. The computer docking simulation was then performed to determine the most plausible binding sites between the model structure and target gases, trimethylamine, ammonia, acetic acid, and o-xylene. According to the simulation result, a series of polypeptide sequences, horp61 for TMA, horp103 for o-xylene, horp109 for ammonia, and horp193 for acetic acid as recognized molecules were designed for gas sensing purposes. Preparing these peptides as corresponding gas sensing probes, the results showed a high relative sensitivity response of 6.7 for TMA (probe horp61), 5.1 for o-xylene (probe horp103), 11 for ammonia (probe horp109), and 28 for acetic acid (probe horp193), respectively. These results indicate that peptide mimicking of binding domain on olfactory receptor opens a new window and offers a novel strategy for the further development of recognized materials for gas sensing.

Synthetic peptide mimicking of binding sites on olfactory receptor protein for use in 'electronic nose'

A putative tertiary structure model of the dog's olfactory receptor (olfd canfa) is established in this study. By using a target odorous compound (trimethylamine), it is possible to locate the most plausible binding sites between the receptor model structure and the target odorous molecules through computer docking simulations. The two short oligo-peptide sequences (orp61 and orp188) for trimethylamine sensing were identified, synthesized, purified and coated onto the surface of the separate piezoelectric gold electrodes. These two peptides show a high binding capability for trimethylamine. To further enhance the sensitivity of the polypeptides towards the target compound, the polarity and the degree of docking were changed by a site-specific modification technique. The orp61 sequence was modified by substituting two amino acids in the binding pocket resulting in 33% increase in sensitivity towards trimethylamine and reduced noises from other non-target chemicals. The techniques used in the present study offer a unique approach for synthesizing peptides in mimicking binding domain of olfactory receptors. The approach can be easily applied to further development of recognized molecules for gas sensing, especially for use in 'electronic noses'.

Structural factors affect the interactions of anticardiotoxin antibodies and cobra venom cardiotoxins

Two antibody preparations against cardiotoxins were raised by immunizing rabbits with cardiotoxin 1 and cardiotoxin 3, respectively. The two antibody preparations showed precipitin reactions with cardiotoxins 1, 2, 3 and 5, respectively. However, the results of competitive enzyme-linked immunoassay revealed that the respective cardiotoxin molecules exhibited different reactivity toward anticardiotoxin antibodies. Moreover, the order of reactivity with antibodies was not in line with the degree of their sequence identity. This suggest that the anticardiotoxin antibodies may recognize conformational epitopes rather than sequential ones in the toxin molecules. Alternatively, the four cardiotoxins reacted well with the antibodies in the absence of competitor, suggesting that sequence variations with cardiotoxin molecules may not exclusively influence the potential use of the anticardiotoxin antibodies for the neutralization of the activity of cardiotoxin variants.