Saturday, May 01, 2010

NPI’s and Influenza



# 4539



NPIs are Non-Pharmaceutical Interventions – ways to reduce the spread of a disease - and have been a frequent topic in this blog over the years.   


NPI’s can be as simple as hand hygiene, covering your coughs, and avoiding crowds, or can involve the use of personal protective barriers like N95 or surgical masks, latex or vinyl gloves, and eye protection.


School closures, public education, staying home when sick, and engineered barriers to avoid exposure are also examples of NPIs.


And the evidence to date is these steps, if widely implemented, can make a real difference in the spread of an epidemic like Influenza.

Pharmaceutical solutions, most notably vaccines, take months to develop and deploy.  The next pandemic flu to erupt may not be nearly as mild as the 2009 strain, and may hit far more suddenly. 


The goal, in those early months before a vaccine becomes available, is to reduce the spread of the virus as much as possible.  In this way, the burden on health care facilities, and toll of absenteeism and on the lives of those effected can be reduced.





NPI’s have been described as being like slices of Swiss cheese, with each containing large holes through which the virus can pass, but when stacked on top of each other, can provide an effective barrier.


While it is known that these measures can help reduce influenza transmission, there are many open questions regarding their relative merits, cost effectiveness, and optimum combination.  


Unknown too, is exactly how influenza is transmitted.   

Large droplet spread, via coughing and sneezing, is assumed to be the primary mode of transmission, but the exact role of fomites (contaminated inanimate objects we may touch), and the role of fine aerosolized particles are only beginning to be understood.


Allison E. Aiello of the University of Michigan is one of the researchers that has been looking for answers to these questions, and I’ve featured her team’s work a number of times.


Michigan NPI Study: A Closer Look
Study: Effectiveness of NPIs Against ILI's
Study: NPI's Can Help Prevent Spread Of Flu-Like Illnesses


Aiello’s team has recently published their findings in the May issue of the American Journal of Infection Control.   The abstract is available, but it requires a subscription to access the main article.


Luckily we’ve a pretty good summary available from MedPage Today. First the abstract, then the link to the MedPage article.


Research findings from nonpharmaceutical intervention studies for pandemic influenza and current gaps in the research

Allison E. Aiello, et al.

AJIC: American Journal of Infection Control - May 2010 (Vol. 38, Issue 4, Pages 251-258, DOI: 10.1016/j.ajic.2009.12.007)

In June 2006, the Centers for Disease Control and Prevention released a request for applications to identify, improve, and evaluate the effectiveness of nonpharmaceutical interventions (NPIs)—strategies other than vaccines and antiviral medications—to mitigate the spread of pandemic influenza within communities and across international borders (RFA-CI06-010).

These studies have provided major contributions to seasonal and pandemic influenza knowledge. Nonetheless, key concerns were identified related to the acceptability and protective efficacy of NPIs. Large-scale intervention studies conducted over multiple influenza epidemics, as well as smaller studies in controlled laboratory settings, are needed to address the gaps in the research on transmission and mitigation of influenza in the community setting. The current novel influenza A (H1N1) pandemic underscores the importance of influenza research.




Non-Drug Approach Can Slow Spread of Pandemic Flu

By Michael Smith, North American Correspondent, MedPage Today

Published: April 30, 2010

Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner

Nonpharmaceutical interventions, such as handwashing campaigns, can have a significant impact on the spread of the pandemic H1N1 flu, researchers said.


But an analysis of 11 CDC-supported studies reveals key gaps in the research, according to Allison Aiello, PhD, of the University of Michigan Ann Arbor, and colleagues.


The researchers, writing in the May issue of the American Journal of Infection Control, called for large intervention studies, conducted over multiple flu seasons, to assess the impacts of such things as handwashing, cough etiquette, and mask wearing.


Research is also needed into the psychosocial and cultural barriers that make some groups reluctant to accept such measures, Aiello and colleagues said, as well as lab studies to pin down how the flu is transmitted.

(Continue . . .)

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