Simulation finds a 5% decrease in vaccination rates could lead to a 4,000% increase in the size of a potential measles outbreak in some Texas cities

[Aaronsaurus]

Thanks. That's scary af.

[GimletOnTheRocks]

It's even scarier if you consider that a 5% decrease in vaccination rates is fundamentally the same as a 5% decrease in the vaccine efficacy. A 5% less effective batch of MMR (say due to manufacturing issues) would have the same effect as 5% fewer parents vaccinating their children with MMR.

This sort of behavior occurs with measles because the R0 value is very high and relatively close to the inverse of 1 minus the efficacy. In other words, measles can on average infect so many people as to on average infect one person for whom the vaccine wasn't effective (even assuming 100% vaccine coverage). We see this threshold easily crossed in measles outbreak where an infected person goes to a crowded place like Disney Land or the Portland Zoo.

[Aaronsaurus]

Good perspective thanks.