Croakey is introducing a new feature: reports from each week’s @WePublicHealth guest tweeter will be published here at the homepage.
In the past these summaries were published at the @WePublicHealth archives, where you can see the records for 2014-2019. We hope the new arrangement will be useful for readers, and also increase the visibility and impact of @WePublicHealth guest tweeters.
The article below is an edited summary of last week’s contributions from Professor Guy Marks, @Marks1Guy, Professor of Respiratory Medicine at UNSW, and President of the International Union Against Tuberculosis and Lung Disease, @TheUnion_TBLH.
Across issues ranging from the climate bushfire crisis to tuberculosis, air pollution and asthma, his underlying message was “we must do better”.
Guy Marks writes:
My perspective is a Sydney-based respiratory physician, formerly the head of respiratory medicine at Liverpool Hospital, and an epidemiological researcher working in air pollution, chronic respiratory disease (asthma and chronic obstructive pulmonary disease, or COPD) and tuberculosis (TB).
I am also passionate about global health. For the last 15 years I have been actively engaged in TB research in Vietnam. I am also a member, and currently President, of the International Union Against Tuberculosis and Lung Disease, which is a 100-year-old global public health organisation.
I’m excited to have been given this opportunity to engage with the Twitter-sphere about public health. This is a challenging and exciting time for public health in Australia. The issue that literally consumes us all right now is the bushfires.
The effects of the bushfires on health include breathing and heart problems, due to prolonged exposure to smoke, and anxiety and other mood disorders, related to the trauma and dislocation directly associated with the fires. It is likely that there will be other health effects.
In many cases, it is hard to draw a direct causal link to the fires but an excess of deaths and illnesses that is linked in time and place with the fires and smoke probably means that the fires are responsible (“where there is smoke, there is fire”, so to speak).
This disaster, like others, requires a complex and multi-layered response. The response begins with prevention. Like many health problems, the actions required for prevention lie outside the health domain. Doctors and health care workers deal with the consequences but must look to others for action on prevention.
In this case, global warming is the primary driver of the increased duration and intensity of the fire season. Global action to reduce global warming is urgent and Australia must take a leadership position.
Comprehensive responses needed
Given that global warming is now upon us, we also need to take additional actions, advised by experts in fire management, to mitigate the risk of fires and the risk that humans will be impacted by them.
Finally, once again advised by experts, we need to provide our fire services with all the resources they need to fight fires now, and in the future, bearing in mind that the resources required will be substantially more than was considered adequate in the past.
Assuming that, despite efforts at prevention, fires will continue to occur, we also need to do better in protecting people from the health effects of fire and smoke.
The role of masks, filters, air filtration devices and smoke refuges, together with the effect of certain behaviours, such as avoiding exercise and staying indoors, needs to be investigated so that health authorities can give better, evidence-based advice in future episodes.
Impacts on those who are vulnerable, such as those with pre-existing heart and lung disease, pregnant women, infants and the elderly needs to be considered. They may need special intervention.
The role of medicines in treating the consequences of smoke exposure needs to be elucidated.
We need better guidance about when to advise people to relocate. Finally, we need to consider interventions to promote resilience and capacity to recover, both in individuals and in affected communities.
Hence, there is an agenda for research and for action (see more about this in a previous Croakey article).
We must acknowledge the need for a complex and comprehensive response to the fires. It is not enough to simply rebuild and restore. We need to mitigate the risk, adapt and prepare for the future.
Focus on air pollution
The current bushfire crisis has focused the minds of many on the health effects of climate change and also the adverse impacts of air pollution.
Hopefully we can harness this energy and interest to advocate for real action to address the underlying causes: fossil fuel combustion for transport, electricity generation, heating, cooking and manufacturing.
We need to know more about the key sources of pollutants in various settings and to design the most effective policies to mitigate the exposures.
The problem is severe and obvious, but the solution is complex and requires ecological, agricultural, sociological, behavioural and economic analysis.
Of all the environmental causes of ill-health, air pollutants are, by far, the major contributor to deaths and burden of disease.
Air pollution is a particular problem for people in poor countries, where the capacity to abate the exposures and mitigate their effects is weakest.
Other sources of air pollution may also be important in low and middle income countries including: fossil fuel combustion for transport, electricity generation, heating, cooking and manufacturing. We need to know more about the key sources of pollutants in various settings and the design the most effective policies to mitigate the exposures.
Bushfires, deliberate burning of forests for land-clearing, biomass burning for agricultural purposes have all caused major public alarm recently. This is not a new phenomenon. The prolonged exposure to very high levels of particulate (PM2.5) pollution over very large, populated areas is unprecedented in Australia and in the developed (rich) world is NOT unprecedented globally.
People in south and south-east Asian countries commonly have prolonged exposure to very high pollution levels in their cities. This is often, at least in part, attributable to agricultural burning and the smoke is probably not that different to bushfire smoke.
Events at the Australian Open tennis in Melbourne, where players suffered coughing and distressing symptoms while playing in heavily smoke-polluted air, drew international focus to the issue of air pollution and health.
It seems faintly ironic to me that the impact on elite tennis players seems to be attracting a great deal more attention that the impact of people living and working in these cities in poor countries.
The International Union Against Tuberculosis and Lung Disease is currently publishing a series of articles on environmental health as a global health issue. Here is an article from The New England Journal of Medicine, ‘Sounding the Alarm on Climate Change, 1989 and 2019’.
Air pollution and climate change are first order issues for global health.
Of all the environmental causes of ill-health, air pollutants are, by far, the major contributor to deaths and burden of disease. Air pollution is a particular problem for people poor countries, where the capacity to abate the exposures and mitigate their effects is weakest.
A primer on health protection
Challenges such as the bushfire crisis, thunderstorm asthma epidemics in Melbourne, and recent outbreaks of viral pneumonia in China focus attention of the diverse nature of airborne threats to health.
Those who are committed to protecting human health need to have wide angle of view, a flexible and subtle approach to detecting hazards and effective systems for communicating information and implementing responses.
Health protection comprises:
1.Mitigating the effect of known adverse environmental exposures either by (A) removing the toxic exposure or (B) detecting the exposure and removing people from exposure
2.Building resistance/resilience.
3.Treating the adverse health effects.
The fields of infectious diseases, environmental epidemiology and toxicology have helped us to identify many environmental hazards to health including microbial pathogens that are communicable (such as tuberculosis, SARS, MERS CoV and influenza) and many others than are non-communicable (such as Legionella, house dust mites) and non-microbial pathogens such as nitrogen dioxide, particulates, smoke, heavy metals, nerve gas, pollens, salt, sugar and cigarette smoke.
This sample bag of harmful exposures gives some idea of the problems we face in protecting human health by controlling exposure to known adverse environmental exposures:
1.The list is very extensive and substantial resources are required to monitor all these exposures.
2.The list of known adverse exposures is incomplete. There are almost certainly many to be discovered.
3.Many exposures are only adverse when exposure is above a certain threshold, or alternatively, the risk is related to the dose.
4.Some hazardous exposures cannot be measured.
Other options
We need to continue to pursue this approach to protecting human health through environmental monitoring and controls, treatment and isolation of patients and animals with certain infectious diseases and security. However, it cannot be the only approach to protecting human health.
The second element of protecting the population, building resistance to the adverse effects of toxic exposures in populations, has traditionally focused on immunisation against infectious diseases. However, this is a very limited lens through which to view this.
For example, there is good evidence that regular use of low-dose inhaled corticosteroids by people with asthma reduces their risk of death by 85 percent. There is some evidence that those who were using them prior to the onset of the thunderstorm epidemic in Wagga in 1997 were protected.
This was the basis of a public health campaign promoting the use of inhaled steroids among those at risk in the southern NSW area every spring. We need to consider other strategies for building resistance. This may be relevant to protection against the effects of pollution.
While some of the syndromes we seek to protect against (such as tuberculosis) are well-defined, readily identifiable and clearly linked to action, many others, such as outbreaks of acute gastrointestinal or respiratory illness, are not, and can only be suspected as being due to a hazardous exposure due to clustering in time, space or person.
Many of the challenges we now face, and will face in the future, including bioterrorism threats, outbreaks of novel respiratory viral illnesses and weather-related hazards, are unexpected, unpredictable and not previously known.
Their cause can only be identified by investigation after the cluster (or epidemic) is recognised. We need to expand our capacity to use diverse sources of information and methods of analysis to identify, in a timely manner, when unexpected clusters of events have occurred and to ascertain as much information as possible about the nature of these clusters. The first of these raises the alert and the second directs the response.
It becomes feasible to direct two forms of action: investigation to identify causative factors, for example, using case control studies, leading to the implementation of environmental controls; and action to mobilise additional health care interventions for the affected individuals.
We need a systematic and national response to the airborne threats to health. The current fragmented approach does not serve us well. We can do better. We must do better.
Managing asthma
Asthma is a global health problem. My research career started in asthma over 30 years ago, working with the late Professor Ann Woolcock.
Many people think of asthma as first-world disease affecting rich people.
In fact, most deaths due to asthma are in India and other countries of the “global South”. The Global Asthma Report provides an excellent overview of the problem of asthma, including the number of people affected, the deaths, the problems with treatment and what we know about causes.
At one level the problem of asthma is complex (a “wicked” problem). It is a heterogeneous poorly defined disease entity. In other words, not everyone with asthma is the same. In most cases we do not know what causes asthma.
Personally, this is a great frustration to me, as I have spent a large part of my working life investigating the causes of asthma.
Not knowing the cause, we do not know how to prevent the disease. We also do not know how to cure the disease. We cannot permanently “switch off” asthma with any known treatment.
So, if we can’t prevent it and we can’t cure it, what can we do about asthma? One of the major problems for people with asthma is “attacks”, episodes of worsening symptoms, lasting hours to days, that are distressing, disabling and, in some cases, dangerous and life-threatening.
We do have good ways of preventing attacks. For most people with asthma, inhaled corticosteroids (ICS) are the most effective treatment for prevention of attacks.
Unfortunately, many people with asthma do not have access to this class of medicine: either because they are not available, they are not prescribed, they are too expensive or they are not used effectively. This is particularly a problem in poor countries, where the ICS are difficult to obtain.
In the absence of this class of medicine many people with asthma use short-acting reliever type medications (“Ventolin” and similar blue inhalers), oral steroids (prednisone), or other oral medicines (e.g. theophylline, antibiotics, etc). These are cheap and available but either ineffective or hazardous when used inappropriately.
A recent series of studies published in the NEJM points towards a new treatment paradigm, using a combination inhaler (formoterol combined with an inhaled steroid), taken as required for symptoms. This was effective in reducing the risk of attacks in people with asthma.
Globally, there are about 1,000 deaths per day due to asthma. This shocking toll could be substantially reduced if there was better access to effective treatments for asthma: inhaled corticosteroids (preferably in the form of combination inhalers with formoterol).
We need to do more to ensure that effective treatments for chronic diseases, such asthma, are available to those who need them. This is an important part of the Universal Health Coverage agenda that is generally ignored by those pursuing it.
We can do better. We must do better.
The TB scandal
Every year more people die due to TB (over two million) than any other infectious disease.
This is in spite of the fact that we have had tests to diagnose TB disease and infection (chest radiograph, sputum microscopy and culture, and Mantoux test) for more than a century, as well as effective anti-TB drugs for more than half a century.
Effective use of these tools has led to #EndTB in many countries, including Australia, most European countries and north America. However, globally, with over 10 million cases of #tuberculosis occurring every year, we have a massive fail.
Why is this so?
The reasons are complex and probably include factors related to the risk of transmission of TB, such as crowding and poor living conditions, and poor access to health services. However, in my view this is not enough to explain the global failure to eliminate TB.
My hypothesis is that the effectiveness of the National Tuberculosis Campaign that ran in Australia from 1945 rested on two key elements: universal regular screening for TB and payment of a tuberculosis pension to all people receiving treatment for TB.
The first of these was an essential public health intervention to find all infectious cases in the community and prevent them from infecting others (thereby interrupting the epidemic) and the second reduced stigma and financial disadvantage for people with TB and encouraged completion of treatment.
The 1950s to 1960s saw a dramatic decline the new cases of TB in Australia. The effect was so dramatic that by the mid-1970s the campaign was terminated and other, less costly interventions (directly observed therapy, contact investigations) have been
We have recently completed and published a study in Vietnam to test part of this hypothesis: that regular screening of the entire population could interrupt transmission and rapidly reduce the number of cases of TB.
Vietnam has a high burden of tuberculosis: about 15 people in every 1000 in the general adult population have active infectious tuberculosis. In our study, conducted in a province in the far south of Vietnam, we found that screening reduced the prevalence of TB by nearly 50 percent.
Furthermore, although screening only took place in adults, we found that the number of children with TB infection was reduced by 50 percent in the screened villages. This is particularly encouraging. It shows that screening adults for TB actually prevents TB infection – the precursor of TB disease.
In my view, this proof-of-concept study is very encouraging evidence to support the value of population-wide screening for TB for TB elimination.
I think we need to go “back to future” to #ENDTB. We need to rediscover the lessons of the past: the value of mass screening for TB and the value of financial support (in the form of a pension) for people suffering from TB.
I believe these two interventions hold the key to TB elimination. We need to do further work to test this hypothesis and work out how to implement it effectively and efficiently. If we do this, I believe we truly can end the global scourge of TB, once and for all. Ten million cases and two millions deaths due to TB is a scandal in the modern age.
We can do better. We must do better.
• This week, Croakey editor Dr Ruth Armstrong is guest tweeting for @WePublicHealth while on the road in the United States. Follow the discussions and travel photos at @WePublicHealth.
