An optimal control theory approach to non-pharmaceutical interventions

Lin, Feng; Muthuraman, Kumar; Lawley, Mark

Emerging influenza is threatening the world with the next pandemic [1] . The current swine flu caused by a novel H1N1 virus has infected a documented 182,166 humans, killing 1,799 from April 2009 to August 2009 [2] . The World Health Organization (WHO) declared the outbreak to be a pandemic because of growing worldwide cases [3] . Currently, the severity of the outbreak is moderate as most people recover from infection without the need for medical care [4] . However, if the virus mutates and achieves the ability to cause severe illness, it will kill more people and overwhelm the health system. Vaccination is the most effective means of pandemic mitigation. Vaccine production is a complex multi-step process which involves development, manufacturing, and delivery processes and current levels of vaccine production capacity are inadequate. Thus many uncertainties exist in every step and effective vaccines are typically available well after the viral strain has emerged [5] [6] [7] [8] . For instance, vaccines against the H1N1 strain are still under development and will remain in short supply by November 2009 [9] . Current stockpiling of antiviral drugs will also be in short supply and their efficiency will be limited once a pandemic occurs [7, 8] . Public health systems need to be prepared for cases when effective pharmaceutical interventions are unavailable. Non-pharmaceutical interventions (NPIs) are necessary to delay and dampen the pandemic before pharmaceuticals become available [7] . Recommended NPIs include: (1) social distancing: school closure, workplace distancing, restricted public gathering and travel;