氣候變遷對愛滋病毒反應的影響
www.thelancet.com/hiv Vol 11 February 2024
2023 年全球氣溫創下 10 萬年來最高紀錄,其中一些月份是有史以來最熱的月份。 儘管各國在 2015 年《巴黎協定》中承諾將全球氣溫上升限制在比工業化前氣溫高出 1·5°C 以內,但 2022 年溫室氣體排放量仍達到創紀錄水準。 據估計,除非兌現從化石燃料轉型的承諾,否則到 2100 年氣溫可能會上升 2·7°C。 全球暖化和人為氣候變遷不僅對地球的環境系統產生深遠影響,而且看似不可阻擋的氣溫上升也將對人類健康和福祉產生災難性影響,對受愛滋病毒影響的人群產生影響。
氣候變遷的後果——例如降水和氣溫增加、極端天氣事件、海平面上升和空氣污染——都對人類健康有直接影響。 根據《刺胳針》2023年健康與氣候變遷倒數計時報告報道,2022年歐洲創紀錄的炎熱夏季導致6.2萬人死亡,極端洪水影響了巴基斯坦和奈及利亞的數百萬人,非洲乾旱導致當地糧食不安全影響超過4,600 萬人。 根據世界衛生組織稱,2030年至2050年間,氣候變遷每年可能導致約25萬人因營養不良、瘧疾、腹瀉和熱壓力而額外死亡。 人類健康在氣候變遷討論中的重要性日益受到人們的認可,COP28是第一次將健康作為核心主題的COP會議。
36 億人生活在極易受氣候變遷影響的地區,其中許多人尤其受到愛滋病毒的影響。 最近的一份愛滋病前線報告討論了一個框架,該框架顯示了氣候變遷和愛滋病毒之間複雜的相互關聯性。 移民和人口流離失所的增加、糧食不安全、經濟壓力、衝突、傳染病和衛生基礎設施的侵蝕可能會增加愛滋病毒感染率,並惡化愛滋病毒感染者的健康和福祉。 對愛滋病毒計畫和愛滋病毒感染者的影響可能表現為獲得預防、檢測和治療服務的機會減少、治療依從性差、營養不良和免疫力下降。 其他影響可能會導致愛滋病毒風險增加(例如,由於食品的不安全性導致更多的性交易 www.thelancet.com/hiv Vol 11 February 2024)以及對受愛滋病毒影響最嚴重的人群的歧視增加。 這些影響因影響愛滋病毒感染者的現有脆弱性而放大。
人們對氣候變遷對愛滋病毒的直接和間接影響知之甚少,但研究已開始揭示氣候緊急情況對愛滋病毒應對措施的影響。 《愛滋病前線》報告重點介紹了撒哈拉以南非洲國家的模型數據,這些數據顯示,由於氣溫升高且碳排放量沒有減少,到 2050 年,愛滋病毒感染病例將增加 1,100 萬至 1,600 萬。 乾旱事件會影響愛滋病毒的流行,馬拉威的一項研究顯示,乾旱事件後愛滋病毒的盛行率增加了 15%。 對非洲報告的系統性審查顯示,在乾旱情況下,愛滋病毒治療依從性受到與糧食和水不安全有關的經濟和生計相關挑戰的影響最大,並有可能增加愛滋病毒傳播和抗藥性。
愛滋病毒的結果也可能受到媒介傳播病原體傳播疾病增加的影響。在2023 年IAS 會議上,Nathan Ford(世界衛生組織,瑞士日內瓦)討論了由於高緯度地區全球氣溫升高而導致真菌病原體地理範圍可能擴大,以及這如何導致愛滋病毒感染者疾病發病率和嚴重程度增加。 需要提高意識、監測、預防和治療來應對這些感染。
氣候變遷是一個生存威脅。 最容易受到氣候變遷最嚴重和最直接影響的人群與受愛滋病毒影響尤為嚴重的人群之間存在大量重疊。 儘管氣候變遷與愛滋病毒之間的相互作用很複雜且尚未完全闡明,但愛滋病毒感染者和處在愛滋感染風險者已經感受到了這種影響。 愛滋病毒計畫必須考慮並監測氣候變遷的潛在影響。 ■ 刺胳針愛滋病毒
Effect of climate change on the HIV response
2023 saw the highest global temperatures in over 100 000 years, with some of the hottest months on record. Greenhouse gas emissions reached record levels in 2022 despite commitments by countries in the 2015 Paris Agreement to limit the global temperature increase to less than 1·5°C above pre industrial temperatures. Estimates suggest a potential 2·7°C increase by 2100 unless commitments to transition from fossil fuels are met. Not only do global warming and anthropogenic climate change have profound effects on the planet’s environmental systems, but the seemingly inexorable temperature rise will also have catastrophic effects for human health and wellbeing, with implications for populations affected by HIV.
The consequences of climate change—such as increases in precipitation and temperature, extreme weather events, sea level rise, and air pollution—all have direct effects on human health. As reported in the 2023 report of the Lancet Countdown on health and climate change, record-breaking hot summers in Europe in 2022 caused 62 000 deaths, extreme flooding has affected millions living in Pakistan and Nigeria, and drought in Africa has caused local food insecurity affecting more than 46 million people. According to WHO, between 2030 and 2050, climate change could cause about 250 000 additional deaths per year, from poor nutrition, malaria, diarrhoea, and heat stress. The importance of human health in discussions on climate change is increasingly recognised, and COP 28 was the f irst COP meeting to feature health as a core theme.
3·6 billion people live in regions highly susceptible to climate change, and many of those populations are disproportionately affected by HIV. A recent Frontline AIDS report discusses a framework that shows the complex interconnectedness of climate change and HIV. Increased migration and population displacement, food insecurity, economic stress, conflict, communicable diseases, and the erosion of health infrastructure can increase the rates of HIV infection and worsen the health and wellbeing of people with HIV. Impacts on HIV programmes and people with HIV can manifest as reduced access to prevention, testing, and treatment services, poor adherence to treatment, poor nutrition, and reduced immunity. Other effects could see increases in HIV risk (eg, more transactional sex as a result of food www.thelancet.com/hiv Vol 11 February 2024 insecurity) and increased discrimination of populations most affected by HIV. These effects are amplified by pre existing vulnerabilities that affect people with HIV.
The direct and indirect effects of climate change on HIV are poorly understood, but research is beginning to shed light on the consequences of the climate emergency for the HIV response. The Frontline AIDS report highlights modelling data from countries in sub-Saharan Africa that showed a increase of between 11 million and 16 million HIV cases by 2050 as a result of increasing temperatures and no reduction in carbon emissions. Episodes of drought affect the prevalence of HIV, with a study in Malawi revealing a 15% increase in HIV prevalence after a drought event. A systematic review of reports from Africa has shown that, in situations of drought, HIV treatment adherence is most affected by economic and livelihood-related challenges linked to food and water insecurity, with the potential for increased HIV transmission and drug resistance.
HIV outcomes may also be affected by the increased spread of vector-borne pathogens. Changes in the geographical range of malaria in response to climate change are known, but less well understood is the potential for the spread of invasive fungal pathogens responsible for cryptococcal disease, histoplasmosis, and talaromycosis, all of which are serious infections in people with advanced HIV disease. At an IAS 2023 session, Nathan Ford (WHO, Geneva, Switzerland) discussed the potential increased geographical range of fungal pathogens as a result of increased global temperatures at higher latitudes and how this could result in increased disease incidence and severity among people with HIV. Improved awareness, surveillance, prevention, and treatments are needed to tackle these infections.
Climate change is an existential threat. Substantial overlap exists between populations most vulnerable to the worst and most immediate effects of climate change and populations disproportionately affected by HIV. Although the interactions between climate change and HIV are complex and not fully elucidated, people at risk of and living with HIV are already experiencing the effects. It is essential that HIV programmes consider and monitor the potential effects of climate change. ■ The Lancet HIV