Thursday, August 26, 2021

Empirical effectiveness research prior to politicization of public health

I have alluded a number of times to the fact that pre-Covid-19 hysteria, the de facto protocols for dealing with respiratory disease spread did not include masking, general lockdowns, prolonged school closures, etc.  Each of these can be pertinent for short durations under very particular circumstances but are not recommended as a general response.

What I have not done is to go and find some of those research examples.  So here is one which just floated across my virtual desk.  Disease Mitigation Measures in the Control of Pandemic Influenza by Thomas V. Inglesby, Jennifer B. Nuzzo, Tara O'Toole and D.a. Henderson.  It is from 2006.

The threat of an influenza pandemic has alarmed countries around the globe and given rise to an intense interest in disease mitigation measures. This article reviews what is known about the effectiveness and practical feasibility of a range of actions that might be taken in attempts to lessen the number of cases and deaths resulting from an influenza pandemic. The article also discusses potential adverse second- and third-order effects of mitigation actions that decision makers must take into account. Finally, the article summarizes the authors’ judgments of the likely effectiveness and likely adverse consequences of the range of disease mitigation measures and suggests priorities and practical actions to be taken.

So what does their research reveal in terms of effective and ineffective approaches.

There is no question but that another influenza pandemic will occur and that every community needs to be prepared for that eventuality. Influenza is unlike any other disease epidemic in the rapidity with which it spreads and, as it emerges, the number of illnesses that it can cause over a period of a few months. It is unpredictable as to when a pandemic might begin. It could be next autumn or it may not be for a number of years. The world has weathered three pandemics during the past century and will certainly surmount the next one. How much damage the pandemic will cause depends to a large extent on the state of readiness of each community and each metropolitan region and the efficacy and reasonableness of its response. The following is a synopsis of the authors’ judgments regarding possible disease mitigation measures.

Vaccination. Vaccination is, by far, the most important preventive measure, but pandemic strain vaccine will not be available for at least the next season. Meanwhile, communitywide use of the seasonal influenza vaccine is desirable, as it is likely that outbreaks of seasonal flu will occur even if there is pandemic influenza.

Provision for isolation and medical care of influenza patients. A Regional Health Care Operations Committee is a priority need to assure collaboration and cooperation across the community (hospitals, medical care providers, Red Cross, law enforcement, media, and others), both for advanced planning and during the epidemic to assure that the large numbers of flu-infected patients can be cared for in hospital, at home, or in special facilities. Special arrangements are needed for expanding surge capacity in hospitals, for support to permit home care of patients, and for the provision of additional volunteer healthcare staff.

A communication strategy and plans. Open and frequent communications with the public are essential. This involves regular press conferences, hot lines, and provision of information through civic leaders, churches, schools, and businesses. An important message is to request that all who are ill remain isolated at home or in the hospital but to encourage others to continue to come to work so that essential services can be sustained.

Closure of schools. It has been the practice in many communities to close the schools for 10–14 days at the beginning of an epidemic of seasonal flu, primarily because of the number of both teachers and pupils who are absent. This is a reasonable initiative, often expected in many communities, that also serves to demonstrate action on the part of officials. Closing schools for longer periods in hopes of mitigating the epidemic by decreasing contacts among students is not warranted unless all other likely points of assembly are closed (e.g., malls, fast-food restaurants, churches, recreation centers, etc.).  Such widespread closures, sustained throughout the pandemic, would almost certainly have serious adverse social and economic effects. 

Hand-washing and respiratory hygiene. Everyone should be encouraged to wash their hands after coming in contact with people who are ill and to cover their mouths when coughing or sneezing.

Cancelling or postponing meetings or events involving large numbers of people. Intuitively, this would appear to be a helpful adjunct to reduce contacts among people and so mitigate the effects of the epidemic. However, individuals normally have a great many contacts throughout the community on a daily basis: shopping in stores, attending church, traveling on public transport, and so on.  Recognizing that the spread of influenza is primarily by person-to-person contact, any one individual, even in a large gathering, would have only a limited number of such close encounters with infected people. Thus, cancelling or postponing large meetings would not be likely to have any significant effect on the development of the epidemic. While local concerns may result in the closure of particular events for logical reasons, a policy directing communitywide closure of public events seems inadvisable.

Quarantine. As experience shows, there is no basis for recommending quarantine either of groups or individuals. The problems in implementing such measures are formidable, and secondary effects of absenteeism and community disruption as well as possible adverse consequences, such as loss of public trust in government and stigmatization of quarantined people and groups, are likely to be considerable.

Screening passengers at borders or closing air or rail hubs. Experience has shown that these actions are not effective and could have serious adverse consequences; thus, they are not recommended.

An overriding principle. Experience has shown that communities faced with epidemics or other adverse events respond best and with the least anxiety when the normal social functioning of the community is least disrupted. Strong political and public health leadership to provide reassurance and to ensure that needed medical care services are provided are critical elements. If either is seen to be less than optimal, a manageable epidemic could move toward catastrophe. 

They do not include it in the summary but with regards to masking:

Use of Masks and Personal Protective Equipment

Masks and other personal protective equipment (PPE) are essential for controlling transmission of influenza in hospitals. For people who work in hospitals, current CDC guidelines for influenza infection control recommend droplet precautions, including the use of surgical masks.  But HHS planning guidelines also rightly acknowledge that the uncertainties regarding the potential of virus transmission at the start of a new pandemic would recommend that airborne precautions be used in hospitals—that is, N95 masks (already in short supply) or powered air purifying respirators (PAPRs).  Patients would be advised to wear surgical masks to diminish the number of infectious respiratory particles being dispersed into the air, thereby diminishing the likelihood of further spread.

In Asia during the SARS period, many people in the affected communities wore surgical masks when in public. But studies have shown that the ordinary surgical mask does little to prevent inhalation of small droplets bearing influenza virus.  The pores in the mask become blocked by moisture from breathing, and the air stream simply diverts around the mask. There are few data available to support the efficacy of N95 or surgical masks outside a healthcare setting. N95 masks need to be fit-tested to be efficacious and are uncomfortable to wear for more than an hour or two.  More important, the supplies of such masks are too limited to even ensure that hospitals will have necessary reserves. 

No to general lockdowns, to cancellation of events, to forced masking, to anything other than short duration school closures.  Answers known on 2006.  All of these conclusions are much more robustly demonstrated from the emerging data today when we walked away from known effective strategies and instead did performance public health, putting the importance of being seen to do something ahead of actually do things with some empirical grounding.

There was much other research, this study a mere drop in the bucket.  


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