Wednesday, November 28, 2007

Questions Over Quarantines In 1918

 

 

# 1296

 

 

The word for today is, apparently, NPI

 

Non-Pharmaceutical Interventions.

 

Basically, those steps we can take to mitigate a pandemic that don't involve the use of drugs.   

 

 

NPI's include social distancing, quarantine, isolation, handwashing, the closing of schools and other public venues, and the personal use of barriers such as masks, gloves, and gowns.

 

 

Given our inability to rapidly produce a targeted vaccine for any novel influenza outbreak until at least six months into a pandemic, the use of NPI's ranks very high in our public health strategy.   The goal of NPI's  is to reduce the mortality and impact of any pandemic by slowing the rate of transmission of the virus in the community.

 

 

Last February, the CDC released a document called : Interim Pre-Pandemic Planning Guidance:Community Strategy for Pandemic Influenza Mitigation in the United States. (PDF file), that outlines many of these steps.

 

 

All well and good, and most of the NPI's listed, at first glance at least, appear to make sense.  Unfortunately the science behind these recommendations is less authoritative than we'd like, and subject to debate.

 

 

Then in August of this year a study was released by Howard Markel and colleagues at the  University of Michigan that seemed to provide some scientific backup for the NPI strategy, citing evidence that early use of NPI's (particularly quarantines, isolation, and school closings) during the 1918 Spanish flu reduced morbidity and mortality rates.

 

 

Some of the data used in this study has been called into question by none other than John M. Barry, author of The Great Influenza: The Epic Story of the Deadliest Plague in History.

 

 

CIDRAP (Center for Infectious Disease Research and Policy) has an excellent commentary by John Barry on all of this, with a forward by Michael Osterholm.    It is an intriguing read.

 

It seems like a minor point. 

 

Did New York City impose quarantines during the 1918 pandemic?     The authors of the Markel study contend that they did, although John Barry's research raises real doubts.  

 

This isn't a trivial point.  The conclusions of this study, that early implementations of NPI's helped reduce morbidity and mortality, are based in part on the numbers from New York.   If the New York numbers are based on an erroneous assumption (that quarantines were enforced), then the entire study may be considered suspect.

 

This academic dust-up isn't over.  Markel  et Al.  are defending their methods and conclusions.    

 

This debate isn't over.  It's just begun.

 

Even if the Markel study should eventually be proved to be flawed, that won't negate the use of NPI's in a pandemic.   It will simply reduce the scientific evidence we have that they are effective. 

 

Hopefully, we'll keep better records during the next pandemic than they did in 1918, and those destined to go through the pandemic-after-next  will have a clearer understanding of what works, and what doesn't.

 

Until then, the search for the truth continues in academia.  It isn't always pretty, but it is essential.