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“Catch-up” and incomplete HPV vaccination better than nothing

26 Aug, 14 | by Leslie Goode, Blogmaster

Quadrivalent HPV vaccine (HPV4) has been shown to protect against HPV types 16 & 18, which cause 70% of cervical cancers, and HPV types 6 & 11, which cause 90% of genital warts.  Health authorities in the US and elsewhere have therefore recommended routine vaccination of girls (and more recently boys) at ages 11 & 12, and “catch-up” vaccination for women aged 13 to 26. Vaccination programmes in New Zealand (STIs/Read & Fairley) and Australia (STIs/Fairley and Bradshaw) have indicated what can be achieved, given adequate coverage.

For the US and elsewhere there remains a problem of ensuring coverage.  Recent figures from the US Centers for Disease Control and Prevention National Immunization Survey-Teen (NIS-Teen) for 13-17 year-olds ≥1 dose quadrivalent or bivalent vaccine, CDC/MMWR 25.7.14, show levels that remain obstinately low despite year on year improvement, rising from 53.8% to 57.3% (girls), and from 20.8% to 34.6% (boys) between 2012 and 2013.  By comparison, UK uptake on the first 3 years of its programme was 66% (STIs/Sacks & Robinson).  The low US rate is of particular concern because there is considerable evidence from the US and UK that it is often those who are most at risk, such as racial and ethnic minorities, who are most likely to miss out on vaccination (STIs/Niccola & Hadler; STIs/Sacks & Robinson; STIs/Liddon & Hadler).  Tantalizingly, the Report estimates at 91.3% the coverage for ≥1 dose by age 13, if HPV vaccine had been administered to adolescent girls born in 2000 during health care visits when they received another vaccine.

This, of course, raises the question why this opportunity is being missed.  The authors cite the disquieting datum that, when NIS-Teen asked parents to identify reasons for non-vaccination, one third of parents of girls and over half of parents of boys reported that their child’s clinician had not recommended  that their child receive an HPV vaccination.  They therefore point to the need to address gaps in clinician knowledge and communication skills as well as parental knowledge.  A discussion of apparent difficulty of ensuring the conformity of providers to HPV guidelines has already been discussed by STIs/Kepka & Seraya.

 

Given poor levels of uptake at age 11-12, especially among some of the needier populations, it becomes important to know the effectiveness of catch-up vaccination and incomplete vaccination.  This is made very evident in a recent US cross-sectional study, Brogly & Shi Yang (B&Y), of the relation of cervical abnormalities to HPV vaccination status amongst 235 minority women undergoing routine cervical cytology testing.  Only 54% of these had initiated, and only 33% completed, vaccination – and of those vaccinated, only 3% had received the vaccination before sexual debut.  Their results appear to show that even a tardy, and frequently incomplete, HPV vaccination confers significant benefits on individual women.  Abnormalities (ASCUS, LSIL or HSIL) proved to be considerably reduced amongst the vaccinated group, even where participants had not completed the full course of three injections – RR 0.35 for ≥1 dose as against no vaccination; RR 0.45 for 1-2 doses as against no vaccination; RR 0.26 for completed vaccine as against no vaccination.  If corroborated in further studies, these findings could reinforce argument in favour of the effectiveness of HPV catch-up against those have placed this in doubt (STs/Chesson & Markowitz).

The study also aimed to examine the relationship between vaccination status and HPV genotype, but the sample size was too small to establish anything very conclusive.  STIs/Nielsen & Kjaer claim to demonstrate, with a far larger Danish sample, that low-risk types are frequent in ASCUS lesions, but scarcely ever occur in isolation from high-risk HPV types, where the lesions are more severe.

UNAIDS Gap Report: “The beginning of the end of the AIDS epidemic

20 Aug, 14 | by Leslie Goode, Blogmaster

In advance of the 20th International AIDS Conference in Melbourne 20th-24th July, UNAIDS has published its Report entitled The Gap.  This offers a panoramic survey of progress and challenges to date, graphically presented.

The general sense of a tide having at last turned in the global battle against HIV is borne out by the Report’s account of the increased concentration of the epidemic on certain key fronts where the struggle will henceforth need to be carried on.  Overall, it points to a global decline – and a swiftly accelerating decline – in HIV incidence and AIDS related mortality globally.  New infections have fallen 38% from 2001, 13% over the last three years; mortality has declined 35% since 2005, 19% over the last three years.  The Middle East and North Africa (see STIs/blog;  STIs/Saba & Abu-Raddad; Abu-Raddad & Riedner), and Eastern Europe and Russia constitute the sole exceptions to this pattern (with increases in mortality of 66%, and 5% respectively).

The “flip-side” is an increasingly visible concentration of the epidemic.  Fifteen countries (with Nigeria and S. Africa generally topping the list) account for 75% of the global HIV burden, 76% of last year’s (2013) new infections, and 74% of last year’s AIDS-related mortality.  In view of this, it is no surprise that the major part of the Gap report consists in a series of profiles: first, of the principal world regions, and second key populations (prisoners, transgender etc.).  These recurrently pose the question: “Why am I being left behind?”

Three aspects of the situation as described by the report strike this reader as particularly telling:

-          the proportion of those living with HIV who are still not accessing ART: three in every five.  In Nigeria 80% have no access to treatment.

-          the vulnerability of adult women in sub-Saharan Africa, who alone account for 80% of the 16 million women aged 15 yrs and older who live with HIV.

-          the appallingly low proportion of children living with HIV who receive ART: a mere 24%.

Does risk compensation behaviour neutralize the benefits of voluntary medical male circumcision?

18 Aug, 14 | by Leslie Goode, Blogmaster

The effectiveness and feasibility of voluntary medical male circumcision (VMMC) as a preventative intervention against HIV has been demonstrated in a variety of non-circumcising African communities.  The WHO has designated 14 countries in southern and eastern Africa as priority areas for VMMC scale-up.  Attempts to model the progress of the epidemic have long sought to factor in the potential contribution of VMMC (STIs/Hallett & Abu-Raddad).  However, the possibility of risk-compensation remains an ongoing concern (i.e. that the known preventative effects of VMMC will lead to increased sexual risk-taking).  Current evidence has been largely limited to behavioural evaluations and extended follow-up in populations where RCTs of VMMC were being conducted (e.g. Rakai, Uganda; Orange Farm, South Africa; Kisumu, Kenya).  The evidence has been reassuring, by and large.  Yet it is also inconclusive – for two reasons: first, on account of the rigorous risk reduction counselling invariably provided by these trials, which is far in excess of what would be offered in operational settings; second, due to the lack of certainty as to the preventative effectiveness of VMMC that prevailed at the time when these RCTs were being conducted.  These are precisely the issues that bedevil studies seeking to evaluate risk compensation in the context of pre-exposure prophylaxis (PrEP): see STIs/blog/Marcus & Grant; STIs/blogs/Mugwanya & Baeten.

A recent prospective, longitudinal study conducted in Nyanza Province, Kenya (Westercamp & Bailey) claims to mark an important step forward towards understanding the relation between VMMC and sexual risk-taking in everyday operational settings.  Participants in the study were not exposed to unrealistic levels of risk reduction counselling, and the preventative efficacy of VMMC had already been well established prior to commencement of the study.  Participants were followed up, at six monthly intervals over a two year period, having assigned themselves either to a circumcision (1,5888) or a control (1,599) group, using (as far as possible) audio computer-assisted self-interview questionnaires to investigate sexual behaviour.

The result?  No risk-compensation, apparently.  In fact, the findings show an increase of 30%/6% in condom use at last sex (for the circumcised/control group), and a broadly comparable decline for both groups across a range of indicators, including transactional sex in the last six months (26-12%), most recent sex with a casual partner (20-12%), and having multiple partners in the last six months (26-16%).  The only adverse finding was an increase in sexual activity for both groups among the younger participants – but this seems to be largely explained by transition to married status.

The decline might be due to some limited exposure to HIV education through participation, or reflect “cognitive dissonance” – i.e. the re-evaluation of behaviours in the light of the personal investment involved in getting circumcised.  But there is evidence it might be part and parcel of a decrease in sexual risk-taking in the community at large due to the implementation of the VMMC programme over the period of the study 2008-2011.  A curious finding was the greatly reduced perception of high HIV risk among the “cross-over group” of those 20% of the control group who subsequently chose to be circumcised, as against the perceptions of those who initially assigned themselves to the circumcision group.  This, according to the authors, suggests that men motivated to early adoption of VMMC may represent a higher risk group.  When this finding is taken together with recent evidence of high (90%) acceptance of VTC services among men undergoing circumcision, the case stacks up for ensuring the provision of high-quality counselling as a priority throughout the commencement and rapid initial sale up of VMMC services.

Should bisexuals be considered a population with specific sexual health needs?

28 Jul, 14 | by Leslie Goode, Blogmaster

Across many cultural contexts, men who have sex with both men and women (MSMW) have levels of STIs/HIV comparable to those we find in men who have sex only with men (MSM); but MSMW have often proved particularly hard for health services to access.  Mercer & Cassell (M&C) (UK) and STIs/Beyrer & Baral (B&B) (South Africa) refer to poor rates of HIV testing as compared to MSM (RR 0.31 and 0.62 respectively). Both studies stress the need to find ways of targeting safe-sex messages for MSMW who do not identify as gay.

In an intriguingly entitled reivew of the literature on MSMW sexual health in the US 2008-2013 (“Beyond the bisexual bridge”)  Jeffries  corroborates this general picture of high STI risk and poor accessibility.  But he seeks to get beyond what he considers an obsession on the part of researchers with the role of MSMW as a “bridging” population with women.  He claims this “characterization” is not justified by the research – at least where the US is concerned (Chu & Curran; Satcher & Dean; Kahn & Catania).  He also views it as ultimately detrimental to the sexual health of MSMW, which needs to be founded on the “recognition of MSMW’s unique sexual and social experiences”.

The article reviews both the sexual health, and socio-cultural challenges to MSMW’s health.  Sexual health challenges include: levels of STIs other than HIV equalling and exceeding MSM levels, alongside levels of HIV lower than MSM, yet higher than MSW (as in the UK (see M&C)); also enormously higher levels of injection drug use, sex in exchange for money or drugs, and drug and alcohol use during sex than in MSM; also sex within female networks (as well as male) that imperil sexual health, with a high proportion of female partners having injected drugs, being under influence of drugs during sex, and having concurrent partners.  Socio-cultural challenges include biphobia in society at large, and fairly extreme socio-economic marginalization, as indicated by lack of education, poverty, homelessness and incarceration.

Some corroboration of the role that Jeffries attributes to settled identities in moderating at risk behaviour is provided by the success of a number of ongoing initiatives aimed at black or Latino MSMW.  These all appear to address MSMW’s masculinity concerns and heterosexual identities in a non-judgmental and culturally sensitive manner.  Men of African American Legacy Empowering Self (MAALES) has been evaluated in a RCT discussed in an earlier blog (STI/blog/Are bisexuals well served by interventions that assume gay identity?).  Jeffries also mentions: Hombres Sanos; the Bruthas Project; the Enhanced Sexual health Intervention for Men (ES-HIM).

A puzzle remains in the lower susceptibility of MSMW, as against MSM, to HIV – alongside equivalent or higher susceptibility to other STIs .  Jeffries discusses this, but offers no explanation.  Could the less than expected levels of HIV in MSMW be the result of an association between MSM identity and sexual networks that carry particular risk of HIV transmission?

HIV epidemic among heterosexual non-intravenous drug-users: could HSV-2 co-infection be the driver?

24 Jul, 14 | by Leslie Goode, Blogmaster

Why such high HIV prevalence reported for non-injecting drug users who are predominantly heterosexual?  This reaches 37% in Porto Alegre, Brazil; 43% in China; 13% in Canada; 20% in Florida; 19% in New York City; 24% in Portugal; 29% in Russia?  Possible factors include impaired decision making under the influence of drugs or the exchange of sex for drugs.  Studies published in STI Journal also propose high prevalence of, amonst other STI infections,  HSV-2 as a particular risk for HIV amongst non-injecting drug users (STIs/Plitt & Taha), and comparable groups, e.g. Tanzanian female bar-workers (STIs/Riedner & Hayes).  HSV increases susceptibility to HIV through disruption of the epithelial surface, as well as increasing transmissibility from persons co-infected with HSV and HIV through raising levels of plasma HIV-1 RNA.

A recent study of non-injecting drug users (NIDU)  (Jarlais & Cooper) attending a New York drug detoxification centre and a methadone maintenance programme – 785 over the period 1995-1999 and 1,764 over the period 2005-2011 – claims that HSV-2 co-infection is the principal driver of HIV transmission, especially amongst female NIDUs.  Over both periods that latter group shows: very high levels of HSV-2 mono-infection (78% and 86% respectively), high levels of HIV/HSV-2 co-infection (10% and 21%, and negligible HIV mono-infection.  The pattern is similar though less pronounced in the case of males.  As between the two periods (1995-1999 & 2005-2011) there is a doubling in the prevalence of HIV (from 7% to 13% overall) which is represented more or less uniformly across all ethic and behavioural groups.  Though the specific quantitative contribution of HSV-2 to the HIV infection cannot be determined by this type of study, these results suggest that the rise in HIV among NIDUs should be considered an epidemic of HSV-2/HIV co-infection, and that HSV-2 is likely to be the driver of the increased HIV incidence.

So what should be done to minimize HIV transmission among non-injecting drug users?  The obvious response would be suppressive HSV-2 therapy.  Unfortunately, however, trials have not as yet shown this to be effective in reducing HIV transmission (STIs/Mujugira & Wald; Barnabas & Celum).  The authors recommend further research into the effectiveness of higher dosages of HSV-2 suppressive therapy: also of HSV-2 suppressive therapy prior to ART or in combination with ART – since a recent study found evidence of HIV in the semen of men who had reached viral suppression on ART (Politch & Anderson).  At all events, HIV/HSV-2 co-infected NIDUs would appear to be a priority for ART as prevention, and the authors recommend providing ART to this group at all CD4 cell counts.  (New York introduced in 2011 a new policy of offering ART to all HIV sero-positive persons in the city regardless of CD4 count).

IDU and HIV in the Middle East: a brief window of opportunity?

22 Jul, 14 | by Leslie Goode, Blogmaster

There are regions of the world where intravenous drug use (IDU) is known to have a key role in evolving HIV epidemics.  Information about IDU populations, on the basis of which to motivate and inform public health interventions, can be scant and of poor quality (STI/Aceijas & Hickman).  This deficiency is particularly important to address, given the possibility in some contexts of these populations serving as a bridge into other populations (STI/Reza & Blanchard; STI/Decker & Beyrer), and the practicality and cost-effectiveness of interventions that could make a difference (e.g. needle/syringe exchange programmes) (STI/Demyanenko & Vagaitseva; STI/Boci & Hallkaj).

The Middle East and North Africa (MENA) is among the regions of the world in which IDU might be expected to be a key epidemiological factor – given the availability and cheapness of drugs (US$ 4 per gram of heroine, as against US$ 100 in Europe).  But, as recently as 2005, the region was characterized as “as real hole in terms of HIV/AIDS epidemiological data” – let alone in terms of IDU HIV data.  STI/Reza & Blanchard in an alarming study of epidemiological bridging in Pakistan do not include other MENA countries among the epidemiological parallels to which they refer – perhaps because of the lack of data.

A recent systematic review by Mumtaz & Abu-Raddad (M&R) may go some way to addressing this need, but points to the importance of further research.  M&R review and synthesize data from sources (e.g. international and regional databases, and country-level reports) relevant to actual and potential HIV risk for IDU populations across 23 nations in MENA.  They estimate average IDU over the region at 0.24 per 100 adults, and HIV prevalence in these populations averaging 10-15% (both figures comparable with what we find in other regions).  Among the 10 (23) nations for which good evidence is available, 6 show concentrated epidemics suddenly emerging over the last ten years (Iran, Pakistan, Afghanistan, Egypt, Morocco, Libya), at national (Iran, Pakistan) or local (Afghanistan, Egypt, Morocco, Libya) level; 4-5 others show low level epidemics.

This study delivers a strong message.  Data from countries for which there is evidence of low level IDU HIV epidemics suggests “moderate HIV potential” (i.e. high levels of unsafe practices reflected in prevalence of Hepatitis C and other STIs).  The same, for all anyone knows, may also be true for those 13 countries for which the evidence is not available.  Pakistan saw rocketing levels of HIV (from near 0% to 23% in six months) following introduction of the infection into IDU populations.  Low prevalence countries, including those about which we know little, may have only a brief “window of opportunity” before they experience a comparable explosion of HIV among their own IDU populations.  This, according to M&A makes it imperative to conduct studies in those 13 countries, and to implement further rounds of surveillance in those for which there is already evidence, with a view to making timely and effective interventions.  M&A cite, as evidence of the patchy coverage of IDU by existing prevention services over the region, the very small proportion of the IDU population reporting ever being tested for HIV as indicated by studies conducted in Morocco and Pakistan.

Cultural constraints on the uptake of voluntary medical male circumcision in Eastern and Southern Africa

23 Jun, 14 | by Leslie Goode, Blogmaster

My previous blog spoke of the recent PLoS-Medicine Collection on the progress of a UNAIDS initiative for a five-year scale-up of Voluntary Male Medical Circumcision (VMMC) for HIV prevention in 14 high priority Eastern and Southern African countries.  Among the papers, Ashengo & Njeuhmeli (A&N) and Macintyre & Bertrand (M&B) deal with what the authors of the Collection Review identify as one of the two major obstacles to deployment of the initiative: the insufficiency of demand, especially amongst older (aged 25+) men.  They consider the cultural and social constraints on demand, as these are reflected in the very different cultural contexts of Zimbabwe and Tanzania/Iringa Province (A&N) and Kenya/Turkana County (M&B).

In Tanzania, where circumcision as a cultural practice is widespread, A&N’s figures show a proportion of older men presenting for VMMC through to 2013 of c.6%.  Very few of these were reached through campaigns, as opposed to routine services.  In Zimbabwe, by contrast, where circumcision is not widely practised, the proportion of aged 25+ circumcised through the program was c.33%.  There was much less difference in the age profiles of those accessed by campaign and routine service modalities.  Whereas, in Tanzania there is a cultural perception “that male circumcision is most appropriate before or during puberty” (and older men do not come to VMMC services in a setting that includes mostly adolescent clients) – in Zimbabwe there is less difference between age groups, either in respect to numbers circumcised or preferred mode of access.  Intriguingly, this suggests that the existence of a cultural norm of circumcision may be more of an obstacle than an asset where older clients are concerned.  Of course, this contrast has to be set in the context of the overall advantage in terms of HIV/AIDS prevention conferred on countries like Tanzania by the existence of the cultural norm.  On difficulties of demand in Zimbabwe specifically, see STI/Kaufman & Ross.

A further insight into the potentially negative impact of existing cultural practice is cast by M&B.  Focus group discussions and in-depth interviews in the rural, traditionally non-circumcising area of Turkana County, Kenya, draw attention to perceptions of circumcision amongst older men that are not favourable to their widespread up-take, especially by the older age-group.  The first is the identification of circumcision with the cultural values of other (potentially hostile) groups.  Interestingly, the negative impact of the perception of the practice as imposed from outside, or else non-traditional, has been demonstrated in other non-circumcising cultures (STI/David; STI/Madhivanan & Klausner). The second is the understandable perception that HIV/AIDS is a “new” problem among young urban dwellers (most Turkana sufferers belong in this category) and that circumcision, as a response to this “new” problem, is appropriate for the young, not for older, rural people (see also responses in a study on the acceptability of VMMC in Rwanda: STI/Mbabazi).

The impression that emerges from both studies is that the existence of a cultural practice of circumcision amongst certain groups in a region does not always confer an advantage where potential clients for VMMC are in the older age groups (25+).  In particular, good uptake of VMMC services by adolescents may actually prove an obstacle for older men, reinforcing the cultural perception of VMMC as primarily for younger men.  In this situation service providers may face a choice between strategies that yield the greatest number of circumcisions through an exclusive focus on the younger age-group, and strategies designed to attract a wider diversity of age-groups.

 

The roll-out of UNAIDS voluntary medical male circumcision programmes in sub-Saharan Africa: Is it working?

18 Jun, 14 | by Leslie Goode, Blogmaster

Voluntary medical male circumcision (VMMC) has been demonstrated to reduce HIV acquisition by 60% or more.  WHO and UNAIDS have recommended that VMMC form a part of comprehensive HIV prevention programming in regions of high prevalence, such as sub-Saharan Africa.  Mathematical modelling suggests that the achievement of 80% VMMC coverage within 5 years in 14 countries in Eastern and Southern Africa would avert 3.36m new HIV infections. In the light of this the UNAIDS Joint Strategic Action Framework (JSAF) has set out the goal of circumcising 20.2 million men in five years across these countries. The challenges this represents on both the supply and the demand side are comprehensively discussed by STI/Gray & Kigozi.

A recent PLoS – Medicine Collection considers the progress thus far, and through to 2016, of this initiative.  The Collection Review (Sgaier & Njeuhmeli (S&G)) offers a useful survey. The year preceding the JSAF and the first two years of the initiative have seen yearly VMMC of 0.88m, 1.7m, and 2.9m respectively. If we assume current rates of growth, this would give a cumulative total of 17.5m circumcisions by 2016 – about 3m short of the 20.2m target; if we assume no growth, the cumulative total for this period would be 13.7m.  The scale-up of VMMC over the last three years has been impressive. Still, rates of year-on-year growth have fallen from 109% (2011) to 72% (2013).  S&G identify two factors impeding the achievement of the JSAF goal: first, insufficient funding, largely as a result of the failure of international donors to step in alongside the US President’s Emergency Plan for AIDS Relief (PEPFAR) (which currently bears 80% of the cost); second, the lack of – or failure to create – sufficient demand for VMMC in the targeted countries, especially amongst the older element (i.e. aged 25+) of the population.

The 13 papers in the collection deal with issues around supply of VMMC – such as maintaining quality of service during scale-up (Jennings & Njeuhmeli; Rech & Bertrand; Rech & Njeuhmeli) and optimizing efficiency in service delivery (Rech & Njeuhmeli;  Mahvu & Bertrand; Perry & Bertrand).  But, more interestingly, they also deal with the problem that S&G identify as one of the two main obstacles to achieving the JSAF goal – that of creation of demand (Macintyre & Bertrand; Ashengo & Njeuhmeli).  This important issue will be covered in my next blog.

Gonorrhoea antimicrobial resistance: is UK antibiotic stewarding policy shows “some success”

14 May, 14 | by Leslie Goode, Blogmaster

A widely circulated press release from the Society of General Microbiology’s (SGM) Annual Conference 2014 (April 14th – 17th) reports that Health for England’s Gonorrhoea Resistance Action Plan, according to representative, Dr Catherine Ison, “has shown some success in delaying the onset of treatment failure to the oral antibiotic cefixime”.  At issue here is the policy of switching to intra-muscular ceftriaxone with azithromycin as the first line treatment for gonorrhoea in the face of alarming evidence of an increase in gonococcal resistance to oral cefixime – a policy that aims to delay the emergence of cefixime resistance, and so “steward” our last remaining antibiotic defences against the infection (STI/blogs/Ison & Lowndes).

So the reprieve continues, we are to assume – in the absence from the press-release of even a head-line figure in support of Ison’s bare claim to “some success”.  If we turn to the Gonococcal Resistance to Antimicrobials Surveillance Programme’s last report (GRASP 2012: published October 2013) we find that the prevalence of GUM isolates exhibiting decreased susceptibility to cefixime (MIC ≥0.125 mg/L) declined significantly in MSM from 17% in 2011 to 7% in 2012, and in females from 3% in 2011 to 1.6% in 2012 (though isolates from heterosexual men show little change in cefixime MICs), following alarming increases in resistance from 2007-2010. In June 2013, Ison & Lowndes (I&L) (STI/blogs/Ison & Lowndes) noted a “striking association” between this decline in resistance and the change in UK prescribing practice referred to above, though “causality cannot be attributed to this observation” (Ison: Doctor’s Channel).  (Any argument for causality would, as a minimum, require precise information regarding the timing of the policy change – which is conspicuously absent from the I&L paper).  The SGM press-release appears to indicate a continuation of the same downward trend, and presumably offers further endorsement for the policy adopted at some point in 2011.

The SGM devoted a Report to sexually transmitted infections in 2013 (SGM – 2013). Anti-microbial resistance (most urgently, at present, in gonorrhoea) heads the list of three research challenges.  Recommendations include investment in research to track the impact of new interventions (e.g. optimizing the use of existing antibiotics), and extending lessons learned on gonorrhoea to understand treatment failure in chlamydia and mycoplasma genitalium – as well, of course, as initiating a drug development strategy that addresses the current problems of market failure.  Interestingly, however, the second challenge, that of rapid diagnosis of bacterial STIs, is also highly relevant to the problem of stewarding antibiotic defences.  The future development of enhanced diagnostic point-of-care tests based on genomic rapid sequencing techniques could enable a more “tailored” response to infection, based on profiling antibiotic susceptibility in the individual case, which would facilitate switching back to “abandoned” antibiotics where the their resistance profile disappears from the local population.

Needless to say, the development of new antibiotics (potentially Cempra’s solithromycin or AstraZeneca’s AZD0914), and of rapid sequencing-based diagnostic techniques, are in the future.  Meantime, the reprieve achieved through stewarding of cephalosporins may, says Ison, be short-lived.

 

 

 

Responding appropriately to differentials in HIV care outcomes – are local answers needed?

12 May, 14 | by Leslie Goode, Blogmaster

The recent discovery of the preventative potential of anti-retroviral therapy (ART) (STIs/blog/modelling ART impact)  throws into sharp relief the challenge represented for the US by the very inadequate proportion of its 1.2 million HIV+ citizens (<30%) who are virally suppressed.  Nunn & Mayer  use new geographical mapping tools to bring home forcibly the epidemiological dimension of the problem by visualizing the association which HIV+ incidence/mortality show with social status and ethnicity as reflected in residence.  The picture that emerges is of an enormous concentration of the problem in certain very circumscribed neighbourhoods.  To give just one example of what is best conveyed in the diagrams (figures 1 & 2), age-adjusted death rates rise from <11.2 per 1000 people living with AIDS (PLWHA) to 19.4-32.5 per 1000 PLWHA as one passes from a predominantly white neighbourhood with large gay population and high rates of HIV/AIDS (≥2142 per 100,000 population) to the predominantly Afro-Caribbean neighbourhood of Harlem.

For Nunn & Mayer (N&M), these visualizations raise the question whether either (1.) the allocation of resources to metropolitan areas, or (2.) the nature of the strategies employed by public health interventions, reflects the very geographically focussed nature of the problem of HIV/AIDS incidence and mortality.  Their response to the epidemiological dimension of the problem revealed by their mapping tools is to urge the importance of implementation research as a vital component of HIV initiatives.

N&M’s emphasis on viraemia suppression, rather than just HIV incidence, accords well with their insistence of the epidemiological importance of the local dimension.  Retention in care is a factor that is presumably amenable to initiatives at local level – whereas HIV incidence may owe much to transmission through sexual contacts external to the community (STI/blog/Grabowski & Gray).

Their message is in line with increasing public health interest over recent years in “program impact evaluation methods that take account of the complex interactions among interventions and between intervention packages and the context into which they are introduced” (STIs/Aral & Blanchard).  There is surely a strong argument in favour of designing interventions to take place within an evaluative framework allowing a reflection on the kind of program mix likely to be most effective in a given context.  On the other hand, N&M may be in danger of undervaluing the potential of interventions of a non-localized character that act on the socio-economic determinants of the HIV problem, and especially non-retention in care – for example, the wider provision of medical insurance (STI/blogs/ObamaCare).  It would be interesting to see how far a geographical mapping of the incidence of other health problems in New York or Philadelpia coincided with N&M’s mapping of HIV/AIDS mortality.  How far is the effect of “micro-epidemics”, conjured up by epidemiological language, just a reflection of socio-economic determinants that produce identical results wherever they happen to be present?

 

 

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