A Poppe –Laka os Analysis o he
CDC’s 2025 Vaccine–Au ism S a emen :
Epis emological and Me hodological
Conside a ions
Dimas Tadeu Co as
Uni e si y o S˜ao Paulo
[email p o ec ed]
Abs ac
In No embe 2025, he U.S. Cen e s o Disease Con ol and P e en-
ion (CDC) e ised i s accine sa e y communica ions, s a ing ha he
claim “ accines do no cause au ism” is no an e idence-based conclu-
sion. This a icle analyzes he epis emological implica ions o his e-
ision h ough he philosophical amewo ks o Ka l Poppe ’s alsi ica-
ionism and Im e Laka os’s heo y o scien i ic esea ch p og ammes. I
a gue ha he CDC’s language mis ep esen s he logical s uc u e o sci-
en i ic easoning and he e iden ial s a us o nega i e causal indings in
epidemiology. F om a Poppe ian pe spec i e, he causal hypo hesis link-
ing accines o au ism has been epea edly es ed and ejec ed. F om a
Laka osian s andpoin , he hypo hesis exhibi s he cha ac e is ics o a de-
gene a i e esea ch p og amme. Consequen ly, he e ised CDC wo ding
e lec s a depa u e om me hodological no ms and in oduces epis emic
ambigui y in o public scien i ic discou se.
1 In oduc ion
Since he la e 1990s, he hypo hesis ha childhood accines cause au ism spec-
um diso de (ASD) has been ex ensi ely in es iga ed. La ge-scale coho s ud-
ies ac oss popula ions ha e consis en ly ailed o demons a e any causal associ-
a ion be ween accina ion and au ism (Taylo 2014, Jain 2015, H iid 2019). In
No embe 2025, he CDC e ised i s websi e language, s a ing ha he claim
“ accines do no cause au ism” is “no e idence-based.” This a icle e alua es
ha wo ding h ough he lens o philosophy o science, pa icula ly he heo ies
o Ka l Poppe and Im e Laka os.
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2 Poppe ian Falsi ica ionism and he Logic o
Causal Rejec ion
2.1 Scien i ic Me hod and Falsi iabili y
Ka l Poppe (Poppe 1959) held ha science ad ances by p oposing bold hy-
po heses and ejec ing hose alsi ied by empi ical es ing. While uni e sal neg-
a i es (“X ne e causes Y”) canno be p o en, speci ic causal hypo heses like:
H1: Vaccines cause au ism
can be es ed and ejec ed i hey epea edly ail empi ical sc u iny.
2.2 Epidemiology and E idence o Absence
Nega i e e idence is no he same as lack o e idence. When s udies a e high-
powe ed, eplica ed, and me hodologically igo ous, consis en null esul s con-
s i u e e idence o absence. This is he case wi h accine-au ism s udies (Taylo
2014, H iid 2019, Jain 2015, IOM 2012).
2.3 The CDC’s Misapplica ion o Poppe ian Logic
By sugges ing ha ejec ion o a causal link is “no e idence-based,” he CDC
implies ha science equi es posi i e p oo o a uni e sal nega i e—an impossi-
bili y in Poppe ian logic. The app op ia e o mula ion is:
“The hypo hesis ha accines cause au ism has been es ed and
alsi ied.”
3 Laka osian Resea ch P og ammes and Degen-
e acy in Science
3.1 The S uc u e o Resea ch P og ammes
Im e Laka os (Laka os 1978) p oposed ha science ad ances h ough esea ch
p og ammes composed o a “ha d co e” o cen al assump ions and a “p o ec i e
bel ” o auxilia y hypo heses. P og ammes a e p og essi e when hey gene a e
no el indings; hey a e degene a i e when hey ely on ad hoc explana ions.
3.2 Vaccine–Au ism Hypo hesis as Degene a i e
The o iginal accine-au ism hypo hesis has mu a ed—shi ing om MMR o
hime osal, aluminum, immune o e load, e c.—wi hou p edic i e success. Each
shi ollowed he alsi ica ion o a p io e sion, indica ing degene acy.
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3.3 Mode n Au ism Resea ch as P og essi e
In con as , cu en au ism esea ch—spanning gene ics, neu ode elopmen , and
en i onmen al ac o s—has p oduced obus , p edic i e models and is he e o e
p og essi e in Laka osian e ms.
3.4 CDC’s F aming and Resea ch P og amme Dema ca-
ion
Failing o ecognize he accine-au ism hypo hesis as degene a i e unde mines
he public unde s anding o why ce ain scien i ic p og ammes a e abandoned.
Laka osian me hodology demands ha science di e en ia e be ween abandoned
and p og essi e lines o inqui y.
4 Bu den o P oo and A gumen om Igno-
ance
The CDC’s s a emen e lec s a classic allacy: he a gumen om igno ance.
Scien i ic easoning places he bu den o p oo on he claiman (“ accines cause
au ism”). The consis en ailu e o his hypo hesis in es ing means i no longe
me i s epis emic neu ali y.
5 Epis emic Responsibili y and Scien i ic Com-
munica ion
Poppe and Laka os emphasized cla i y and me hodological in eg i y. Ambigu-
ous s a emen s abou disc edi ed hypo heses isk con la ing alsi ied heo ies
wi h ongoing deba e and weakening public us in science (Nyhan 2015).
6 Conclusion
This analysis concludes ha :
1. The accine-au ism hypo hesis has been empi ically alsi ied.
2. I cons i u es a degene a i e esea ch p og amme.
3. The CDC’s 2025 s a emen mis ep esen s he epis emic s a us o a alsi ied
claim.
4. A scien i ically accu a e s a emen would be:
“The hypo hesis ha accines cause au ism has been igo ously es ed and
consis en ly ejec ed by high-quali y e idence.”
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Re e ences
[1] Poppe , K. (1959). The Logic o Scien i ic Disco e y. Hu chinson.
[2] Laka os, I. (1978). The Me hodology o Scien i ic Resea ch P og ammes.
Camb idge Uni e si y P ess.
[3] Taylo , L. E., Swe d ege , A. L., & Eslick, G. D. (2014). Vaccines a e no
associa ed wi h au ism: An e idence-based me a-analysis. Vaccine, 32(29),
3623–3629.
[4] H iid, A., Hansen, J. V., F isch, M., & Melbye, M. (2019). Measles, mumps,
ubella accina ion and au ism: A na ionwide coho s udy. Annals o In e -
nal Medicine, 170(8), 513–520.
[5] Jain, A., e al. (2015). Au ism occu ence by MMR accine s a us among
US child en wi h olde siblings wi h and wi hou au ism. JAMA, 313(15),
1534–1540.
[6] Ins i u e o Medicine. (2012). Ad e se E ec s o Vaccines: E idence and
Causali y. Na ional Academies P ess.
[7] Nyhan, B., & Rei le , J. (2015). The oles o in o ma ion de ici s and iden-
i y h ea in he p e alence o mispe cep ions. P oceedings o he Na ional
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