斯科特縣的事件不應再發生
資料來源：剌胳針愛滋病毒醫學期刊/www.thelancet.com/hiv Vol 5 October 2018/財團法人台灣紅絲帶基金會編譯
美國的阿片類藥物危機造成了巨大的痛苦和數十萬人之喪生，2017年在美國成為超過機動車事故死亡的另一死因。僅在2017年，因服用藥物過量導致死亡的人數估計有72,000人，其中超過63,000人是由於阿片類藥物，超過了美軍在越戰期間死亡人員的數量（約58,000人）。美國人藥物過量死亡人數最多的年齡層是在24-35歲之間。在2016年，這個重要年齡組中有五分之一的人死因涉及阿片類藥物。阿片類藥物危機已經產生了額外的公共衛生威脅，因為有些依賴阿片類藥物的人已轉變為注射阿片類藥物（包括海洛因），可預見的是C型肝炎病毒（HCV）和愛滋病毒和愛滋病的爆發將接踵而至。美國印第安那州斯科特縣，只是全美在2011-15年期間最不穩定的爆發愛滋病毒和C型肝炎病毒（HCV）流行地區當中之一，亦是被美國疾病控制和預防中心（CDC）視為這些傳染性感染之爆發流行係處於高風險的26個州中的220個縣之一。
而斯科特縣和其他許多其他類似的地方轄區，所背負的不僅只是阿片類藥物使用和依賴所導致的高負擔外，並且也有多重的限制，尤其主要是法律的和政治上的，讓對應於有物質濫用障礙的人其預防、治療和照護的反應變得遲鈍。聯邦政府長期地禁止資金提供於針頭和注射器交換計畫之禁令，當疫情爆發時仍持續在斯科特縣運作，而印第安納州限制性的法律進一步禁止這些服務提供，是促成斯科特縣爆發流行的一個成因，另外針對所有物質成癮尋求治療的人而其醫院和治療設施能力的不足則又是另一原因。更甚者，雖然「患者保護與平價醫療法」( Patient Protection and Affordable Care Act , ACA )為美國各州提供了慷慨的補貼，願意擴大醫療補助計劃以增加國家的藥物治療能力，但許多州拒絕接受這些資金。斯科特縣和美國其他類似的縣可以透過提前去提供這些基本服務以減少愛滋病毒（和C型肝炎病毒）爆發的程度嗎？
在剌胳針愛滋病毒醫學期刊中，Gregg S Gonsalves和Forrest W Crawford報告了一項模擬研究調查去探究在斯科特縣中由注射毒品的人傳播愛滋病毒導致爆發的動力學。使用疾病預防控制中心公開的爆發流行之可用數據和一項新的基於易感受情況移除的模型之估計方法，他們計算出未經確診的愛滋病毒感染之區間估計值、病例發現率和隨著時間的推移愛滋病毒感染病例數估計值的上下限。這些估計值可以去評估早期介入措施對疫情規模可能的預防影響。
Gonsalves和Crawford報導了在爆發流行過程中早期的介入措施，在減少愛滋病毒感染人數上可能會有很大的影響。在斯科特縣愛滋病毒感染的估計值為183-184例，作者發現，如果在2013年1月已有公共衛生措施實施，該疫情可能會在發生56次或更少的感染次數後停止，至少避免127例感染。如果介入措施業於2011年4月即開始實施，則感染的人數可以減少到為10人或更少，至少預防了173例個案。雖然此模型沒有考慮HCV傳播，但在爆發期間感染愛滋病毒的人中約有80％的人也被發現有HCV合併感染，強調了這些病原體在此類爆發中流行病學上緊密的連結，這些發現具有好幾個真實且重要性的含義。在注射藥癮者中有效的愛滋病預防措施以中斷傳播的爆發流行早已發展成熟。當面對美國阿片類藥物流行此種嚴重的公共衛生危機時，卻在實施這些公共衛生措施時遭遇法律和其他結構上的障礙是不能被接受的。印第安納州州長Mike Pence在斯科特縣爆發流行時，他在2015年表現出了相當的領導力。當爆發的規模導致了宣布為突發的公共衛生事件時，他反對共和黨大會並允許有限的減害服務措施。但是，正如Gonsalves和Crawford已經表明，這些介入措施對這個縣的很多人來說是來晚了。面對此巨大的流行我們迫切需要規模相稱的公共衛生介入措施，需要資源、策略、服務提供者之參與，以及來自地方和國家，州和聯邦當局積極的領導。對斯科特縣爆發流行延遲回應明顯地已經發生，而這些在美國大約還有220個有爆發流行類似風險的縣則不應該重複地被延誤。
No more Scott Counties
The opioid crisis in the USA has caused enormous suffering and the loss of hundreds of thousands of lives, and in 2017 surpassed motor vehicle accidents as a cause of death in the USA. In 2017 alone, of 72 000 estimated deaths resulting from overdose, more than 63 000 were due to opiates, exceeded the number of US military personnel who died during the Vietnam war (about 58 000 people). The greatest number of people who died of drug overdoses were Americans aged 24–35 years. In 2016, one in five deaths in this vital age group involved opioids. The opioid crisis has generated additional public health threats because some individuals who are dependent on opioids have transitioned to injecting use of opiates (including heroin), and outbreaks of HIV and hepatitis C virus (HCV) have predictably followed. Scott County, IN, USA, where one of the most volatile HIV and HCV outbreaks occurred in 2011–15, is just one of 220 US counties in 26 states deemed by the US Centers for Disease Control and Prevention (CDC) to be at high risk for outbreaks of these transmissible infections.
What Scott County and many of these other jurisdictions share is not only high burdens of opioid use and dependency, but also multiple, predominantly legal and political, restrictions that have blunted prevention, treatment, and care responses for people with substance
misuse disorders. The longstanding ban on federal funding for needle and syringe exchange programmes
operative in Scott County at the time of the outbreak, and restrictive Indiana state laws further prohibiting
these services, were one component that contributed to the Scott County outbreak, and inadequate hospital and treatment facility capacity for all those seeking treatment for drug addiction was another. Furthermore, although the Affordable Care Act offered generous subsidies to US states willing to expand Medicaid programmes to increase capacity for drug treatment, many states refused to accept these funds. Could earlier provision of these basic services have reduced the extent of the HIV (and HCV) outbreak in
Scott County, and other US counties like it?
In The Lancet HIV, Gregg S Gonsalves and Forrest W Crawford report a modelling study investigating the dynamics of the HIV outbreak as it spread through people who inject drugs in Scott County. Using publicly available data on the outbreak from the CDC, and a novel estimation approach based on the susceptible-infectious removed model, they generated interval estimates of undiagnosed HIV infections, case-finding rates, and upper and lower bounds of estimates of HIV infections over time. These estimates enabled assessment of possible preventive effects of earlier interventions on the scale of the outbreak.
Gonsalves and Crawford report that interventions earlier in the course of the outbreak could have substantially reduced the number of HIV infections. Of the estimated 183–184 HIV infections in the Scott County HIV outbreak, the authors found that if public health measures had been implemented in January, 2013, the epidemic might been halted after 56 or fewer infections, averting at least 127 cases. If interventions had begun in April, 2011, the number of infections could have been reduced to ten or fewer, preventing at least 173 cases. Although the model did not account for HCV transmissions, some 80% of people who acquired HIV during the outbreak were also found to be HCV co-infected, underscoring the tight epidemiological linkage of these pathogens in such outbreaks.
The implications of these findings are several and of real importance. Effective HIV prevention measures are well established for interruption of transmission in outbreaks among people who inject drugs. Legal and other structural barriers to the implementation of these public health measures are unacceptable in a public health crisis as severe as the US opioid epidemic. Mike Pence, the Governor of Indiana at the time of the Scott County outbreak, showed considerable leadership in 2015. He went against Republican party convention and allowed limited harmreduction services as the scale of the outbreak led to a declaration of a public health emergency. But, as Gonsalves and Crawford have shown, these interventions came too late for many people in the county. We urgently need public health interventions of commensurate scale for this enormous epidemic, which will require resources, strategy, provider engagement, and proactive leadership from local, country, state, and federal authorities. Delayed responses to the Scott County outbreak clearly occurred and, with about 220 US counties at risk of a similar outbreak, these delays should not be repeated.
www.thelancet.com/hiv Vol 5 October 2018