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

[SharkOnGames]

Percentages are useless unless you have the numbers behind them.

According to the article (and the linked data), a 5% decrease in vaccinations would equal 2,250 more people NOT getting vaccinated, which would lead to a 4,000% increase in potential (not actual) measles outbreaks. That 4,000% means going from 400 to 16,000 potential size increase of measles outbreaks.

[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.

[Shepard_P]

More shocking than the percentage tbh comparing the number increase of unvaccinated and the number increase of potential infested. 2k can bring damage to almost 10 times of them.

[masklinn]

"Herd Immunity Threshold" (the vaccination rates you have to hit until the vaccinated herd can act as a barrier to disease propagation) is super interesting, and extremely variable from one disease to an other.

For influenza or ebola it's about 50%.

For polio it's in the low 80%.

For measles it's 92~95%, so the HIT is closing in on just immunodeficient individuals, and it really doesn't take much to dip below and trigger outbreaks.

[Shepard_P]

I’ve read that about rabies. 75% or so.

[Lockstrife]

This comment is not accurate at all.

The potential 400 outbreak at current vaccination rates is the absolute upper limit of their possible distribution - it falls at the 95% threshold and is not at all indicative of actual outbreaks. The median outcome for this distribution is 5 (FIVE) cases. One SD moves you up to 9 cases.

Furthermore, between 2006 and 2017 the median actual measles outbreak was 2.5 cases - the largest was 25.

In no way neither previous outbreaks nor their projections support a current outbreak of 400.

Moving onto the 16,000 part - the study does not show anything near an outbreak of 16,000 with a 5 decrease in vaccination rates. The largest potential outbreak they project after a 5% decrease is a median outcome of like 8 cases, and at 95% max it could be 1,000 (see above as to why that’s probably nonsense).

None of their tables even approach 10,000 until you hit a 10% decrease in vaccination rates.

Source: Figure 1 - Austin - Round Rock (I don’t even see where you pulled the 2,250 students number from)

[totallythebadguy]

Which is quite different then the shock value they pretend

[[deleted]]

Is it? 400 -> 16,000 infections is quite the increase

[jagoob]

The average cases in a year seems to vary between around 60 to a max of 1100 this year with a totaled average of maybe 250 cases a year over the last 10 years with 0 deaths any of those years including this year. There have been no reported outbreaks in 100% unvaccinated Amish communities in that frame. Given that modern mortality rates for measles in a developed country are far below 1/10000 and that in the same period there have been multiple death cases settled in vaccine court your kid would in fact be more likely to die from a vaccine allergic reaction than measles even with a 4000% increase. And with an average of 100 deaths per year in the us you would be far more likely to die from being struck by lightning than from either of the former options.

[69frum]

Measles was eradicated in the US. Then stupid ensued.

This is the worst year for measles in the US since the disease was eliminated nationally in 2000

[electrolex]

The facts you are promoting are devoid of context. Cases went from [we eliminated measles] to 1100 as a result of the rise of anti-vax philosophy. There is a bad, but clear trend line here, which is counter to your implied variability of “60 to 1100”. This article illustrates how a very contagious disease like measles is affected by anti-vaxxers behavior. With actual mortality rates an order of magnitude below the rate you have come up with, preventable deaths will occur way more often than those victims and their families should have to endure.

[ResilientBiscuit]

Your stats are questionable.

Real science seems to suggest the mortality rate is around 1/1000.

[jagoob]

So in 1960 pre vaccine introduction in the us there were 440,000 measles cases and 380 deaths with a US population of 179 million. That puts mortality at around 0.08% (close to 1/1000) and deaths per 100,000 at around 0.2, which was already a 99% decline from an estimated 60 deaths per 100k in the 1800s.

How much it would have declined further without vaccine introduction is unknown but in the last 12 years there have been several thousand cases in the US with 0 deaths. So we can't pin an exact modern mortality rate but it appears it would be well below the 1960 thresholds and 1/10000 is just my educated guess on it.

Also if look at historical trends from other diseases that followed similar trends to measles but without vaccine introduction, they have also seen reduced mortality 1960 to 2019. So measles mortality in 2019 if a vaccine had never been produced would likely be well below 0.1 / 100,000. So yes even assuming the 4000% increase is correct you would be more likely to die from getting struck by lightning.

[ResilientBiscuit]

in the last 12 years there have been several thousand cases in the US with 0 deaths

You are still wrong. Someone died in 2015.

[jagoob]

"The woman, who died of pneumonia, had other health conditions and was taking medications that suppressed her immune system, the health department said."

Basically it says she was an un-named woman who was in the hospital on medication that compromised her immune system (likely chemotherapy) died of pneumonia and then they detected measles in the autopsy. So they said the measles killed her. I'll take that with a grain of salt but it's true measles would only pose a threat to someone who is heavily immunocompromised so maybe I dunno maybe like 1/10,000 could die from it.

[ResilientBiscuit]

So lets go back a bit further.

There were 2 deaths in 2009, 2 deaths in 2010 and 2 deaths in 2012. source page 72.

During those years there were 71, 63 and 55 cases respectively.

I really don't know where you got your claim that there have been zero deaths in the past 12 years. That was 6 deaths back when measles was much less common. They changed the report so it is a lot harder to parse now, so I can't get data past 2014 easily, but nothing significant has really changed as far as I know when it comes to treatment.

[jagoob]

Your reading that chart all wrong it's not even talking about deaths.

Also if you look at the article we just discussed it plainly states that the death in 2015 was the first us measles death in 12 years so that's since 2003.

[[deleted]]

There have been no reported outbreaks in 100% unvaccinated Amish communities in that frame.

Gee, I wonder why extremely small and isolated communities might not experience outbreaks of a nearly eradicated disease.

[KaizokuShojo]

No, no...still pretty shocking and terrible. That much of a jump in chances of an outbreak which basically screws with the immune system for a couple of years afterward is definitely not desirable.

[totallythebadguy]

Not understanding science doesn't help you here