Zombies out humans would wipe in just 100 days

Areal-life zombie outbreak would leave the world’s population in shambles, with less than 300 survivors remaining a mere one hundred days into the apocalypse, according to a new study.

Assuming that a zombie can find one person each day, with a 90 per cent chance of infecting victims with the zombie infection, the students from University of Leicester in the UK suggest that by day the hundredth day, there would be just 273 remaining human survivors, outnumbered a million to one by zombies. The team, which presented the findings in the student-run Journal of Physics Special Topics, investigated the spread of a hypothetical zombie virus using the SIR model – an epidemiological model that describes the spread of a disease throughout a population.

The model splits the population into three categories – those susceptible to the infection, those that are infected and those that have either died or recovered.

The initial study did not factor in natural birth and death rates, since the hypothetical epidemic took place over 100 days, resulting in natural births and deaths being negligible compared to the impact of the zombie virus over a short time frame. Without the ability for humankind to fight back against the undead hordes, the students’ calculations suggest that if global populations were equally distributed, in less than a year the human race might be wiped out.

However, in a more hopeful follow-up study, the students investigated the SIR model applied to a zombie epidemic and introduced new parameters, such as the rate in which zombies might be killed and people having children within the nightmare scenario. This made human survival more feasible. The team factored in how over time survivors may also be less likely to become infected after having experience of avoiding or fending off zombies.

They found that it would be possible for the world’s human population to survive the zombie epidemic under these conditions and that eventually the zombie population would be wiped out and the human population would recover.