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Optimal Eradication of Poliomyelitis. Ryan Hernandez May 1, 2003. Why Poliomyelitis?. characterized by fever, motor paralysis, and atrophy of skeletal muscles (acute flaccid paralysis, AFP)
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Optimal Eradication of Poliomyelitis Ryan Hernandez May 1, 2003
Why Poliomyelitis? • characterized by fever, motor paralysis, and atrophy of skeletal muscles (acute flaccid paralysis, AFP) • Deemed eradicated in the Americas since 1994, but still a problem in some countries (e.g. Afghanistan, Egypt, India, Niger, Nigeria, Pakistan and Somalia)
What can be done? • Vaccinations • OPV • does not require trained medical staff/sterile injection equipment, live virus could suffer from disease • IPV • Administered through injection only, dead virus, not completely effective
Questions • In the geographical areas where polio still exists, what steps need to be taken to ensure its eradication for each vaccine? • Can we eradicate polio optimally?
Addressing the Questions Eichner and Hadeler develop a deterministic system of differential equations for each vaccine, and perform equilibrium analysis on the system, but no simulations!!!
Critical Vaccination Level Rw = 12 Rv = 3 => p* = 0.6875
Basic Reproduction Numbers In our developing country, we have Rw = 12 and R1 = 1.2
Critical vaccination p* = 0.986
Discussion • Furthering the research • a model which combines the two vaccine models into one, two-vaccine model. • consider various population ages, since on national vaccination days, it is usually all children aged 6 and less that are vaccinated. • Possibly consider other forms of optimal control.
Optimal Control! Consider the objective functional: Then the Hamiltonian is as follows: Costate variables satisfy these differential equations: