Coronavirus is spreading very fast. Every day the numbers go up exponentially, so it is important to find the optimal mechanism for the most effective disease propagation in a connected network.

A recent study by Russian researchers by the name "Self-isolation or borders closing: what prevents epidemic spreading better?" has discussed the effectiveness of two major strategies that are currently used by the governments.

The classic mathematical model for pandemic SIR (Susceptible—Infected—Recovered) was used for three different types of societies, depending on the probabilities of infection spreading through contacts.

The probabilities in the first model were random, the second type was set as a cluster i-network, where contacts in the clusters can happen, but the probabilities of contacts between two different clusters are set manually. This type of graph emulates the strategy of closing borders to fight the pandemic.

The last model is known as e-network where clusters are made because of self-isolation by every individual unit, where everyone only attempts to contact a few other close people, who are isolated from any other interactions. This makes connections between the clusters only possible through one unit, which differentiates them from the previous model.

According to the study, every individual contact roughly the same amount of people. After ~1000 experiments, the peak of the pandemic was the highest for the first model and the lowest for the last one, the one that simulates voluntary self-isolation.

It still isn't known how accurate the models are for showing the virus spread, but it is a good start for the discussion of what strategy is the best to use in these situations. It is also important to note, that both self-isolation and closing borders are proven to be useful, both practically and statistically.