Optimizing vaccine distribution for an epidemic can be a tricky business because if done incorrectly, the effort may result in an increased incidence of side effects and other untoward consequences. Now researchers from Michigan State University, East Lansing and Hebrew University of Jerusalem, Israel propose a new mathematical model to more precisely calculate when and how much of the vaccine to administer.
The Physics arXiv Blog explains:
What Khasin [Michael Khasin at Michigan State University] and co have done is show that the optimal vaccination protocol is a series of vaccine spikes and that this approach is model independent; ie it should work for any disease.
One problem, however, is that the effect depends strongly on the period of the vaccination pulses. Get this right and the extinction rate of the disease rises exponentially. Khasin and co say there is a kind of resonance effect when the vaccine pulse sequence is close to the characteristic period of oscillations of the disease itself.
But this works both ways. Get the period wrong and you can actually reduce the disease extinction rate. In that case, you can worsen the outbreak.
Nevertheless, this is potentially important work. Vaccines are often in short supply, perhaps because they are expensive, dangerous to store in large amounts, as in the case of anthrax, or have a limited shelf life because the infectious agent regularly mutates as it does for flu.
Chart info: The most probable trajectories in the stochastic SIR model on the plane of the numbers of susceptibles and infected, X1 and X2, respectively, rescaled by N, xi = Xi/N. The dashed line shows a deterministic trajectory toward the endemic state, and the solid line shows the most probable trajectory followed during the fluctuation-induced disease extinction.
More from Physics arXiv Blog: How to Halt Disease with Limited Amounts of Vaccine…
Abstract in arXiv Quantitative Biology: Speeding up disease extinction with a limited amount of vaccine