What will be the average annual number of measles cases in the US from 2025 through 2030?
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CDF
| Lower bound | community | My Prediction |
| <25 | 0.5% | — |
| Quartiles | ||
| lower 25% | 222.5 | — |
| median | 332.1 | — |
| upper 75% | 578.4 | — |
| Upper bound | ||
| >1k | 13.9% | — |
Fine Print
How many measles cases will be reported in the United States in 2025?
What will be the national kindergarten measles vaccination rate in the US for the 2029-2030 school year?
What will be the national kindergarten measles vaccination rate in the US for the 2028-2029 school year?
Comments
I am a bit below the community in my prediction. I think that's because I'm assuming measles vaccinations and cases will revert to the mean. To some extent, low vaccination rates should be self-correcting: as a particular disease becomes more prevalent, people will be more inclined to get vaccinated (and governments will put more effort into getting people vaccinated). I hope the effects of COVID and the shut downs will wash out of the system to some extent by 2030 (these effects are varied! Vaccine hesitancy, supply chain problems, lack of community participation, etc).
FWIW, a support for my thesis that the recent drop in MMR vaccination rates (and all child vaccines in general) was indeed due to Covid: CDC reports (updated March 12, 2024) that
Over 61 million doses of measles-containing vaccine were postponed or missed from 2020 to 2022 due to >COVID-19 related delays in supplementary immunization activities.
I'm sort of doing a hybrid of the two approaches that @dimaklenchin and @Scott_Eastman describe. These are two extremely intelligent individuals that I highly admire.
So on the one hand (the Dima approach), the historical average is somewhere in the 200s, depending on the range of past years you look at. The base rate is very much your friend when doing long-term forecasts. As Phil Tetlock says in Superforecasting, once you get 3-5 years out even the experts are approaching dart-throwing-chimpanzee level.
On the other hand (the Scott approach), a legacy of the COVID-19 pandemic's turmoil is that vaccine hesitancy has undoubtedly gone up, at least on the margins. Pew has some MMR polling here. Overall it's holding up well, with 88% of US adults agreeing that "Benefits outweigh risks" with MMR, unchanged from the 2017 report. Under the surface though, a worrying sign from a public health standpoint is the fact that parents of 0-4 year olds are only 83%, which is lower than parents of older children.
Also there's a distinct partisan split. So from a forecasting standpoint, it would be important to monitor how much it becomes more of a partisan issue, which can cause a cascade of rapidly-changing opinions if it takes hold.
Because of all this, I have my median as the base rate but a stretched right tail.
@johnnycaffeine I'm placing the median at 341, based on @Dima's analysis, plus adding ~27.5% for:
- increased risk of cases coming from abroad
- increased risk due to lower vaccination rates
I'm including a second component of a long right tale (upper 75%, 862) due to: 3. risk that measles will come from a traveller/immigrant to an area of the country (county/school/other area of high concentration of unvaccinated people) and spread quickly 4. possibility that anti-vax movement increases 5. first hand experience from seeing Romania have an increase of 850 cases last week - Romania is not the US, but specific counties in the US have similar vaccination rates - general health and medical accessibility is better in the US, but not radically different. With the number of days that people can be infected and asymptomatic, and the lack of screening of foreign travel to the US, what happens in the rest of the world is relevant.
I'm not forecasting as extremely high as my "gut" tells me, because: 6. average of a 6 year period reduces the impact of an outlier 7. an extreme year MAY lead to increased uptake in vaccinations for subsequent years (low confidence) 8. uncertainty as to the probability that a community with a very low vaccination rate will have an outside case of measles enter their region 9. if areas of low vaccination uptake are rather small, outbreaks may stay relatively contained
The means for the past 15 and past 10 years are 237 and 296. With the annual number of measles remaining IMO a crapshot and my feeling that anti-vax movement is not playing a significant role in the recent drops in average vaccination rates, I see no reason to deviate from those numbers and as a first shot will simply take an average of the two.
@dimaklenchin What do you see as playing a role in the recent drops in the average vaccination rates?
Best I can think it's Covid. As I am looking at the national rates for literally any child vaccine, here is what I see:
- It's all basically a flat line from 2011/2012 to 2019/2020.
- Then there are two years of a drop: 2020/2021 and 2021/2022
- And then, 2022/2023 is identical to 2021/2022 - no longer a drop.
Best I can tell, the anti-vaxx sentiment has not waned or become more reasonable in the past year. Thus, the previous two years drop is probably not explained by antiv-vaxxers either. Now, granted, these are national averages and I have to recall where I was looking at the state level and saw that for some states the gradual drop was continuous all the way to 2022/2023 (which implies that other states saw a rise in vaccinations that compensated this drop - something in my mind also not terribly consistent with the outsize nationwide significant influence of the anti-vaxxers).
Very much open to arguments to the contrary but for now my belief is this: The very vocal anti-vaxx activists on social media have only very limited effects on real-life vaccinations. Alternatively, they are only successful when raving again "untested" mRNA vaccines that "reprogram DNA inside your body" and stuff like this.
I don't see this getting better over the next several years. The anti-vax sentiment that has been exacerbated during the Covid pandemic continues. The candidacy of Robert F. Kennedy Junior has recently been polling at 16%. Not all of his supporters are anti-vax, but he his views which include suspicion of the MMR vaccine have not been disqualifying. I'm influenced by the ease of reaching relatively large numbers in individual communities, plus the increase in people coming to the US who are already infected with measles. In Romania 800 cases were added in the last few weeks. It doesn't take much to reach large numbers. Health authorities are reticent to impose strict controls.
Sergio
·My 75th percentile was already higher than the community's, but I'm putting even more weight on large values now that Trump has nominated Robert F. Kennedy Jr. to serve as the Secretary of the Department of Health and Human Services. From what I can tell, he has a worrying anti-vaccination stance. Given the extreme contagiousness of measles (and the correspondingly high levels of vaccination coverage needed for herd immunity), I think this increases the chance of very large contagions events in the next years (by normalizing communities that do not vaccinate their kids, changing vaccine recommendations, influencing how data about vaccination is presented to the public, etc.).
As I understand, the position of department head requires Senate confirmation, which is now Republican-controlled. Nonetheless, even among the party he is a controversial figure, so I'm still leaving some substantial chance to the possibility that he is withdrawn or is rejected, and a more moderate figure is finally selected.
Perspectus
·@Sergio -- appreciated the reminder to update (re: RFK)
johnnycaffeine
·@Sergio That's a really good point, and it might be interesting to launch a conditional question with this one as the child and a question of whether RFK Jr. gets confirmed as the parent.
Grigfall
·@Sergio Good point, and not one I'd considered before now. I think on balance, his nomination is likely to increase vaccine hesitancy, especially if he is confirmed - he would both have a much wider audience for his claims, and create space for others who think the same way.
That said, I think there is also some chance of a backlash - it seems fair to say that RFK Jr is an eccentric figure, and his association with vaccine hesitancy might also make the movement as a whole seem less credible!
So I am shifting my prediction of an outbreak rightward, but not as much as I might if a different, perhaps more widely palatable, anti-vaxxer were being appointed.
johnnycaffeine
·@Sergio We now have a conditional question here!