To the Editors:
Among the 22 Pacific Island states and territories, Papua New Guinea stands out as having the largest population (6.9 million out of the total of 10 million1) but also a disproportionately large burden of HIV as follows: 19 of every 20 HIV cases reported in the Pacific between 1984 and 2007 were Papua New Guineans.2 The media over many years have spoken of an impending “catastrophe”,3 and the medical literature reported “an unfolding disaster”.4 Some research projected adult prevalence to be as high as 18% by 2010.5,6 Few claims were based on comprehensive or representative data. We present the latest data from the National Department of Health 2009 annual surveillance report (August 27, 2010),7 which depicts a different evolution of the epidemic.
The annual number of new HIV infections detected throughout Papua New Guinea (PNG) has decreased from a peak of more than 5000 cases in 2007 and 2008 to 3711 reported in 2009. This is the first decline in annual HIV infections since 1987 when the first case was identified.8 Importantly, these findings come after a 4-fold increase in both the number of people tested and the number of sites offering testing since 2007.
National adult HIV prevalence estimates are predominantly based on the prevalence among pregnant women. Up until 2007, projections of HIV prevalence using the UNAIDS Estimation and Projection Package9 forecast ongoing increases: by 2009, 1.5% of urban pregnant women were expected to be HIV positive and 2.8% of rural women.10 The trend has actually been downward in urban areas since 2004 and in rural areas since 2006 (Fig. 1), though there were concerns that the combined HIV prevalence of a small number of antenatal clinics was not accurately reflecting HIV prevalence among women overall. The latest (2009) figures come from 116 rural and 61 urban clinics distributed throughout the country (The percentage of the national population from the 2000 National Census report (http://www.nso.gov.pg/census-a-surveys/census-2000) compared with the proportion of 177 antenatal clinics reporting HIV prevalence data in each region is as follows: Southern region—20% of the national population and 27% of the clinics reporting HIV prevalence; Highlands region—38% and 37%; Momase region—28% and 16%; Islands region—14% and 20%. The National Capital District encompassing Port Moresby and surrounding areas is located in Southern Region. It has 4.9% of the national population and 6.8% of reporting antenatal clinics). With 4 of 5 pregnant women attending antenatal clinics,11 these new data suggest adult HIV prevalence is well below earlier predictions: 0.5% of all attendees to rural clinics were HIV positive and 0.8% of attendees to urban clinics.
Fear that the epidemic was generalized throughout PNG has also lessened with data showing a geographic focus in the 5 Highlands provinces, home to around 40% of the population but reporting 60% of the total number of HIV cases in 2009. In addition, almost 75% of all HIV diagnoses in 2009 were among people recorded as being Highlanders, a figure that reflects the ongoing movement of people between provinces in PNG. Another 23% of all cases were detected in the National Capital District, which has just 5% of the national population and includes Port Moresby. These areas are viewed locally as “high-risk settings” for transmission of HIV—the Highlands highway connects the resource rich mountains to the coast with transactional sex common along its length, whereas Port Moresby is PNG's largest urban centre. The rest of PNG is relatively isolated with limited, poorly linked ground access. Behavioral surveillance surveys12 in these high-risk sites found that sex workers (and their clients) reported higher levels of condom use than young urban women who occasionally exchanged sex for money. Importantly, for transmission dynamics, however, only 43% of female sex workers always used condoms. A 2010 study of male, female, and transgender transactional sex workers in Port Moresby found consistent condom use varied from 30% for anal sex, with clients of the opposite sex, to 37% for vaginal sex and 46% for anal sex with same sex clients.13 Although the safe sex message is better known among sex workers in the “hottest-spots” for transmission than among people in lower risk settings, it is being inconsistently applied and especially for the highest risk sex acts.
PNG's HIV epidemic seems to be tracking a different course to the explosive outbreaks in South East Asia in the late 1980s and early 1990s. For example, Thai brothel-based sex workers in that period had on average four partners per day and non-brothel-based sex workers had 1 partner per day.14 By contrast, the behavioral surveillance surveys found that sex workers along the Highlands Highway in PNG had a median of 2-4 clients per week, and young urban women who reported having sold sex did so on average twice a year. Although the intensity of sex trade may be lower in PNG now than in Thailand in the 1990s, the Port Moresby sex worker study still found that 17.6% of those sampled were infected with HIV. Although the intensity of sex trade may be lower in PNG now than in Thailand in the 1990s, the Port Moresby sex worker study still found that 17.6% of those sampled were infected with HIV. This study was not representative of all sex workers in Port Moresby, but it has raised concerns that HIV may have spread more extensively among some high-risk groups than has been previously been documented.
On the other hand, community surveys of the prevalence of sexually transmitted infections have found higher levels than most other countries in Asia-Pacific,15 suggesting risk behaviors are widespread (this led prevention programs to focus on high-risk settings rather than high-risk populations). In combination with the early increases in reported HIV cases and the equal numbers of male and female diagnoses, this high burden of sexually transmitted infections fuelled claims that PNG was experiencing or about to experience an “African epidemic”. HIV epidemics vary from country to country within Africa, but it is it is clear that the PNG situation is nowhere near the extremes of epidemics observed in southern African states. For instance, between 1990 and 2005, HIV prevalence among pregnant women in urban South Africa rose from 0.8% to 30.2%16; over a similar period, HIV prevalence at Port Moresby General Hospital, PNG's largest urban obstetric centre, went from 0% in 1992 when surveillance was established to 1.3% in 2005.
There are a number of ways to interpret the recent epidemiology of HIV in PNG, and these interpretations are not necessarily mutually exclusive. First, the decline in the proportion of people attending voluntary counselling and testing services who test positive for HIV might suggest that the greatly expanded surveillance system now includes more “low-risk” individuals with HIV prevalence figures more accurately reflecting the true community prevalence. This is the most likely explanation.
Second, the trend may represent a real reduction in new cases of HIV due to an effective national response generously supported by international donors. This response includes the formation of the National AIDS Council under the Prime Minister's Department; the prohibition of discrimination on the basis of HIV infection via the HIV/AIDS Management and Prevention Act; the development of a national strategic plan with an AIDS control committee in every province; a focus on high risk settings and the promotion of a “condom culture”; a multisectoral response including strong participation by churches; and the rapid scaling-up of voluntary counselling and testing, surveillance, and antiretroviral therapy. At antenatal sites that offered testing in 2008 and 2009, there was either no change or a decrease in HIV prevalence between the 2 years for 83% of rural sites and 58% of urban sites.
A review of the HIV epidemic decline in Zimbabwe proposed that a reduction in transactional and concurrent sex partners was driven by people's personal experience of family and friends dying of AIDS and that this played a major role in reducing new infections.17 PNG has not experienced AIDS mortality on anything like the scale of Zimbabwe, and although proximate causes of HIV transmission such as partner numbers, condom use in nonmarital partnerships, the prevalence of sexually transmitted infections, or male circumcision may have changed, there are no serial biobehavioural data available to track these changes and their contribution to the HIV epidemic in PNG.
The third way to interpret the changing epidemiology of HIV in PNG is that HIV prevalence can drop when the number of deaths of people with HIV exceeds the number of new people infected. The expansion of HIV treatment services may suggest that this interpretation is less relevant.
PNG is planning a nationally representative HIV prevalence survey this year in part to determine if lower HIV prevalence figures recently observed among pregnant women from numerous sites accurately capture HIV prevalence among the adult population. Although there is now cautious optimism, the risk of an upturn in transmission remains with widespread high-risk behaviors, a prevalence of sexually transmitted infections that is among the highest in the region and possible pockets of higher HIV prevalence such as seen in the Port Moresby survey of sex workers. HIV incidence studies and additional behavioral surveys would be useful to further focus and refine the national response. Successfully addressing HIV in PNG means evaluating the epidemic on its own terms, devising local solutions, and maintaining the remarkable commitment shown by all involved in the response to date.
Ben Coghlan, MBBS, MPH&TM, MAppEpi, FAFPHM*
John Millan, MBBS†
Clement Malau, MBBS, MMed (ComMed), MPH, DTM&H‡
John Kaldor, PhD§
Mike Toole, MBBS DTM&H*
*Centre for International Health, Burnet Institute, Melbourne, Australia
†Capacity Building Service Centre, Port Moresby, Papua New Guinea
‡Secretary of Health, National Department of Health, Port Moresby, Papua New Guinea
§Kirby Institute, University of New South Wales, Sydney, Australia
2. Coghlan B, Gouillou M, van Germert C, et al. HIV in the Pacific
. Melbourne, Australia: Burnet Institute; commissioned by UNAIDS; 2009.
4. Caldwell J, Isaac-Toua G. AIDS in Papua New Guinea: situation in the Pacific. J Health Popul Nutr
6. Kaldor JM, Law M, Henderson K, et al. Impacts of HIV/AIDS 2005-2025 in Papua New Guinea, Indonesia and East Timor: Final Report of HIV Epidemiological Modelling and Impact Study
. Canberra, Australia: AusAID; February 2006.
7. STI, HIV and AIDS Surveillance Unit. 2009 STI, HIV and AIDS Annual Surveillance Report
. Port Moresby, Papua New Guinea: PNG National Department of Health; July 2010.
8. Currie B, Malau C, Naraqi S, et al. Human immunodeficiency virus infection in Papua New Guinea. Med J Aust
10. National AIDS Council Secretariat and the National Department of Health. 2007 Estimation Report
. Port Moresby, PNG: National AIDS Council Secretariat and the National Department of Health; 2008.
12. National AIDS Council Secretariat and National HIV/AIDS Support Project. HIV/AIDS Behavioural Surveillance Survey Within High Risk Settings. Papua New Guinea. 2006
. Port Moresby, PNG: BSS Round 1; 2006.
13. Kelly A, Kupul M, Man WYN, et al. Askim na save (Ask and understand): People Who Sell and/or Exchange Sex in Port Moresby. Key Quantitative Findings
. Sydney, Australia: Papua New Guinea Institute of Medical Research and the University of New South Wales; 2011.
14. United Nations Development Programme. Thailand's Response to HIV/AIDS. Progress and Challenges
. Bangkok, Thailand: UNDP; 2004: 21.
15. Vallely A, Page A, Dias S, et al. The prevalence of sexually transmitted infections in Papua New Guinea: a systematic review and meta-analysis. PLoS ONE
. 2010;5(12):e15586. doi:10.1371/journal.pone.0015586.
17. Halperin DT, Mugurungi O, Hallett TB, et al. A surprising prevention success: why did the HIV epidemic decline in Zimbabwe? PLoS Med
. 2011;82):e1000414. doi:10.1371/journal.pmed.1000414.