Misin o ma ion ega ding esidual DNA in mRNA accine p oduc s
Takeshi Ni a1, Taku Kashiyama2, Yoshihisa Ma sumo o3, Te suya Toyoda4,
Takayuki Miyazawa5, Yuka i Kamijima6, Hideki Kakeya7
1 Di ision o Molecula Pa hology, Resea ch Ins i u e o Biomedical Sciences, Tokyo
Uni e si y o Science, Chiba, Japan
2 Depa men o Pha macology, Jun endo Uni e si y School o Medicine, Tokyo, Japan
3 Labo a o y o Ze o-Ca bon Ene gy, Ins i u e o In eg a ed Resea ch, Ins i u e o Science
Tokyo, Tokyo, Japan
4 Choju Medical Ins i u e, Fukushimu a Hospi al, Aichi, Japan
5 Kyo o Animal Human O ganism Resea ch Ins i u e, Kyo o, Japan
6 Facul y o Pha maceu ical Sciences, Tokyo Uni e si y o Science, Tokyo, Japan
7 Ins i u e o Sys ems and In o ma ion Enginee ing, Uni e si y o Tsukuba, Tsukuba, Japan
Since he epo by McKe nan e al. in 2023 [1], conce ns ha e been aised ha mRNA accines
a e “con amina ed” wi h la ge amoun s o DNA su icien o cause heal h damage. Du ing he
p oduc ion p ocess o mRNA accines, agmen s o he empla e DNA emain in he inal mRNA
p oduc as esidual DNA. Consequen ly, egula o y agencies such as he Eu opean Medicines
Agency (EMA) s ipula e ha esidual DNA in mRNA accine p oduc s should be less han 10 ng
pe dose. McKe nan and subsequen esea che s ha e claimed ha many mRNA accines con ain
DNA le els hund eds o imes highe han he egula o y limi [2]. I mRNA p oduc s con ain
esidual DNA exceeding he egula o y limi , hey a e simply de ec i e p oduc s and mus be
ecalled wi hou ques ion.
McKe nan and many o he esea che s ha e commi ed he undamen al e o o measu ing
small amoun s o DNA using luo och omes ha bind o DNA molecules wi hou i s emo ing
la ge amoun s o RNA p esen in mRNA accines, he eby o e es ima ing esidual DNA le els.
Rega ding his poin , esea che s om he Slo ak Academy o Sciences ecen ly published esul s
measu ing DNA le els in mRNA accines using mul iple app op ia e me hods, con i ming ha
mRNA accines do no con ain DNA exceeding egula o y limi s [3]. Thei measu emen s a e
alid and ho ough, and hei conclusions a e easonable. The e is no alue in calcula ing
o e es ima ed measu emen s using me hods no alida ed by egula o y au ho i ies and
equipmen / eagen manu ac u e s.
Wha abou he quan i a i e polyme ase chain eac ion (qPCR) measu emen s ha ha e been
adop ed by he egula o y agencies and pha maceu ical companies? A ecen pee - e iewed pape
by Speiche , Rose, and McKe nan epo s ha h ee ou o en lo s o P ize mRNA accines
con ained esidual DNA a he le els ha exceeded egula o y limi only when a ce ain speci ic
se o DNA p ime s and p obe was used [2]. This p ime /p obe se is designed o de ec SV40
p omo e /enhance p esen in he empla e DNA o P ize mRNA accines (bu no in he Mode na
mRNA accines). Howe e , since his p ime /p obe se a ge s epe i i e sequences wi hin he
SV40 p omo e /enhance , wo DNA agmen s o di e en sizes may be ampli ied in he PCR
eac ion, making i unsui able o he de ec ion and quan i ica ion o speci ic DNA. The e o e,
measu emen s using his p ime /p obe se a e un eliable, and he conclusion ha DNA exceeding
egula o y limi s was de ec ed by qPCR canno be suppo ed. When o he app op ia e
p ime /p obe se s we e used, no excess esidual DNA was de ec ed. The au ho s should se iously
conside his issue.
Ano he ecen p ep in pape sugges ing ha DNA om mRNA accines has been in eg a ed
in o he human genome has also spa ked discussion [4]. This pape claims o ha e de ec ed 20-
base pai s (bp) o mRNA accine-de i ed DNA in he genome o a bladde cance pa ien .
Howe e , only he pa ien ’s blood samples we e examined, and i emains unclea whe he he
DNA o igina ed om cance cells. Mos c i ically, his pa ien had only ecei ed he Mode na
mRNA accine, ye he sequence o he DNA iden i ied ma ched ha o he P ize mRNA accine.
The mRNA sequences o Mode na and P ize accines di e due o hei espec i e codon
op imiza ion, and he sequence de ec ed in his s udy has wo base misma ches compa ed o
Mode na’s sequence. Fu he mo e, he nucleo ide sequence o he loca ion whe e he 20bp DNA
was inse ed in o he pa ien ’s genome has no been shown. Which pa o which gene in he
genome was modi ied o dis up ed? Despi e he lack o such de ails, he au ho s conclude as i
his DNA agmen caused he pa ien ’s cance . F om he pe spec i e o molecula biology and
oncology, his migh be conside ed an inadequa e and inapp op ia e s udy.
We ha e o med a g oup o in e disciplina y academic esea che s in Japan o e i y such
misin o ma ion. Recen ly, we expe imen ally e u ed he claim ha he p esence o DNA
con amina ion in mRNA accine o mula ions leads o he in eg a ion o DNA agmen s in o he
genome, he eby al e ing gene unc ion o exp ession o induce a ious ad e se e en s [5].
Misin o ma ion abou COVID-19 accines has been p opaga ed no only by an i- accine
scien is s, bu also by p o- accine scien is s, such as he p ospec o he d immuni y and he
unde es ima ion o se e e ad e se e ec s, ep esen ed by myoca di is among young males.
Scien is s mus s i e o es o e us in science, which has been los due o social con usion and
di ision du ing he COVID-19 pandemic.
Con lic s o in e es
The au ho s decla e no con lic o in e es exis s.
Re e ences
[1] McKe nan K, e al. DNA con amina ion in mRNA accines. OSF P ep in s. 2023. A ailable
om: h ps://os .io/p ep in s/os /b9 7m_ 1
[2] Speiche DW, Rose R, McKe nan K. Residual DNA in mRNA accines: analysis and
implica ions. Au oimmuni y. 2025;58(2):e2551517. A ailable om:
h ps://www. and online.com/doi/ ull/10.1080/08916934.2025.2551517
[3] Achs M, e al. Residual DNA analysis in mRNA accines. Resea ch Squa e. 2024. A ailable
om: h ps://www. esea chsqua e.com/a icle/ s-7340318/ 1
[4] Ca anza o M, e al. Possible genomic in eg a ion o accine-de i ed DNA. Zenodo. 2025.
A ailable om: h ps://zenodo.o g/ eco ds/17122912
[5] Ni a H, e al. Expe imen al e alua ion o DNA con amina ion in mRNA accines. Jxi
P ep in s. 2024. A ailable om: h ps://jxi .js .go.jp/index.php/jxi /p ep in / iew/1428
