Hobday Richard, Collignon Peter
Public Health, Hobday Research, Cwmbran, GBR.
Microbiology, Canberra Hospital, ACT Health, Canberra, AUS.
Cureus. 2022 Jun 20;14(6):e26133. doi: 10.7759/cureus.26133. eCollection 2022 Jun.
Outdoors, the risks of transmission of COVID-19 and many other respiratory infections are low. Several environmental factors are known to reduce the viability of viruses and other infectious pathogens in the air. They include variations in temperature, relative humidity, solar ultraviolet radiation, and dilution effects. But one agent that reduces the viability of both viruses and bacteria outdoors, the germicidal open-air factor (OAF), has not been properly recognized for decades. This is despite robust evidence that the OAF can influence both the survival of airborne pathogens and the course of infections. The germicidal effects of outdoor air were widely exploited during the late 19th and early 20th centuries. Firstly, in the treatment of tuberculosis patients who underwent 'open-air therapy' in sanatoria; and secondly by military surgeons during the First World War. They used the same open-air regimen in specially designed hospital wards to disinfect and heal severe wounds among injured soldiers. It was also used on influenza patients during the 1918-19 pandemic. Later, in the 1950s, open-air disinfection and treatment of burns were proposed in the event of nuclear warfare. During the 1960s, the OAF briefly returned to prominence when biodefence scientists conducted experiments proving that open air has a potent germicidal effect. When this work ended in the 1970s, interest in the OAF again fell away, and it remains largely ignored. The COVID-19 pandemic has revived interest in understanding the transmission dynamics and survival of viruses in the air. The pandemic has also stimulated research in the science and practice of improved ventilation to control respiratory infections. Such work is incomplete without an appreciation of the inactivation of viruses and other pathogens by the OAF, but this needs further investigation as a matter of urgency. Research to better understand the conditions under which the OAF can be preserved indoors is urgently needed. We need to review building design with better regard to infection control and patient recovery. But we need to act without delay, as there is already sufficient evidence to show that public health generally would improve if more emphasis was placed on increased exposure to outdoor air.
在户外，新冠病毒及许多其他呼吸道感染的传播风险较低。已知有几个环境因素会降低空气中病毒和其他传染性病原体的活力。这些因素包括温度变化、相对湿度、太阳紫外线辐射以及稀释效应。但是，有一种能降低户外病毒和细菌活力的因素——杀菌性露天因子（OAF），几十年来一直未得到应有的认可。尽管有充分证据表明OAF会影响空气传播病原体的存活及感染进程，但情况依然如此。在19世纪末和20世纪初，户外空气的杀菌作用得到了广泛应用。其一，用于在疗养院接受“露天疗法”的肺结核患者的治疗；其二，在第一次世界大战期间被军医所采用。他们在特别设计的医院病房中采用同样的露天疗法，对受伤士兵的严重伤口进行消毒和愈合处理。在1918 - 1919年流感大流行期间，该方法也被用于流感患者。后来，在20世纪50年代，有人提出在核战争情况下对烧伤进行露天消毒和治疗。在20世纪60年代，当生物防御科学家进行实验证明露天具有强大的杀菌作用时，OAF曾短暂地再度受到关注。当这项工作在20世纪70年代结束时，对OAF的兴趣再次消退，并且在很大程度上仍被忽视。新冠疫情重新唤起了人们对了解病毒在空气中的传播动态和存活情况的兴趣。这场疫情还推动了改善通风以控制呼吸道感染的科学与实践方面的研究。如果不了解OAF对病毒和其他病原体的灭活作用，此类工作是不完整的，但这一问题亟待进一步研究。迫切需要开展研究以更好地了解在何种条件下OAF能够在室内得以保留。我们需要在建筑设计中更多地考虑感染控制和患者康复。但我们需要立即行动，因为已经有足够的证据表明，如果更加强调增加户外空气暴露，总体公共卫生状况将会得到改善。
