Impact Of Non-pharmaceutical Interventions During A Severe Influenza Outbreak

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Main Category: Bird Flu / Avian Flu
Also Included In: Flu / Cold / SARS;  Respiratory / Asthma;  Public Health
Article Date: 07 Aug 2007 - 0:00 PDT

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Non-pharmaceutical interventions, such as closing schools and banning public gatherings, was probably effective in reducing US death rates during the 1918-1919 influenza pandemic, according to an analysis published in the August 8 issue of the Journal of the American Medical Association (JAMA). The article suggests that these non-pharmaceutical interventions should perhaps play a role in planning for future flu pandemics.

Approximately 40 million people died globally during the 1918-1919 flu pandemic, including more than half-a-million in the USA.

The authors write "The historical record demonstrates that when faced with a devastating pandemic, many nations, communities, and individuals adopt what they perceive to be effective social distancing measures or non-pharmaceutical interventions including isolation of those who are ill, quarantine of those suspected of having contact with those who are ill, school and selected business closure, and public gathering cancellations. One compelling question emerges: can lessons from the 1918-1919 pandemic be applied to contemporary pandemic planning efforts to maximize public health benefit while minimizing the disruptive social consequences of the pandemic as well as those accompanying public health response measures?"

Howard Markel, M.D., Ph.D., University of Michigan Medical School, Ann Arbor, and team assessed non-pharmaceutical interventions that took place in 43 cities in the continental USA, starting from September 1918 through to February 1919. They wanted to see whether variations in death rates were linked to timing and how long the interventions went on for. They grouped the non-pharmaceutical interventions into: 1. School closures. 2. Cancellation of public gatherings. 3. Isolation/quarantine.

During the 24 weeks that were analyzed, there were 115,340 excess pneumonia and flu deaths (EDR* of 500/100,000). Each city had adopted at least one of the three main non-pharmaceutical intervention categories.

* (EDR = Excess death rate)

79% of cities analyzed implemented both school closures and public gathering bans concurrently, for an average of four weeks. The implementation of these two interventions was linked to reductions in weekly EDR. Cities that had implemented these non-pharmaceutical interventions earlier took longer to reach peak rates of death, lower peak rates of death, and lower total number of deaths. The link to a lower total number of deaths in these cities was evident, say the authors.

The authors added "These findings contrast with the conventional wisdom that the 1918 pandemic rapidly spread through each community killing everyone in its path. Although these urban communities had neither effective vaccines nor antivirals, cities that were able to organize and execute a suite of classic public health interventions before the pandemic swept fully through the city appeared to have an associated mitigated epidemic experience. Our study suggests that nonpharmaceutical interventions can play a critical role in mitigating the consequences of future severe influenza pandemics and should be considered for inclusion in contemporary planning efforts as companion measures to developing effective vaccines and medications for prophylaxis and treatment. The history of U.S. epidemics also cautions that the public's acceptance of these health measures is enhanced when guided by ethical and humane principles."

JAMA. 2007;298(6):644-654.
www.jama.ama-assn.org

Written by: Christian Nordqvist
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