Three physicists come up with a vaccination strategy.

[Jim__]

I'm not sure why physicists are addressing this problem. Under certain conditions, does this seem like a better approach than current approaches:

"To reduce the infection spread, one can vaccinate all possible susceptible individuals. If they are all willing to be vaccinated and there is enough vaccine for everybody, the vaccination campaign will eradicate the disease with certainty. Very often, however, a large portion of susceptible individuals refuse to be vaccinated. In addition, a vaccine can be in short supply, expensive to produce, or difficult to store."

How to cope with such conditions is the problem tackled by the three physicists: Meerson from the Hebrew University and Prof. Mark Dykman and Dr. Michael Khasin from Michigan State University in the US. (Although presently working in the US, Dr. Khasin earned his doctorate at the Hebrew University.)

The researchers made use of the fact that, even without vaccination, a disease ultimately becomes extinct on its own. But for large populations, the typical time it takes for the disease to disappear by itself can be very long. Essentially, Meerson and colleagues suggested an optimal vaccination strategy that accelerates, in the maximum possible way, this natural process of disease disappearance.

In this strategy, the vaccine must be delivered to the most susceptible populations (say children in a particular class where a certain percentage of the pupils have come down with the flu) in the form of short but intensive vaccination periods, adjusted to match the "ups and downs" of waves that occur in the natural spread of infectious disease.

more ...

[hlthe2b]

1. Disease for which there is only a human host* become extinct...

where there are other animal reservoirs, that is not the case. That is why the only successful disease eradication program thus far has been smallpox (with polio moving towards that goal). Measles, likewise could be eliminated and potentially eradicated with enough resources and substantial effort. Other viruses, with closely related strains affecting any number of animal species, are not really amenable to eradication, (short of removing every single possible "susceptible") even where effective vaccines currently exist.

*and where non-human primates are not naturally infected outside the laboratory.

[HereSince1628]

2. The value of undertanding systems of equations

Last week someone asked about how algebra is practical and in particular how solving systems of equations was relevant to the world.

Also note that modelling of disease using S-I-R models isn't a new way to seek optimal strategies for ending outbreaks, so this isn't exactly a new area. Indeed, Ronald Ross used an S-I-R model in the 1890's to consider the epidemiology of malaria.