Evidence map›Paper›PMID 39777941›Full record

Observational studyPharmacoepidemiology and drug safety2025

Safety Assessment of Influenza Vaccination for Neurological Outcomes Among Older Adults in Japan: A Self-Controlled Case Series Study.

Mitsunori Ogawa, Yoshinori Takeuchi, Yukino Iida, Masao Iwagami, Kohei Uemura, Sachiko Ono, Nobuaki Michihata, Daisuke Koide, Yutaka Matsuyama, Hideo Yasunaga

Abstract readObservational Study
PubMed Full text at PMC Publisher
In one paragraph

Observational study in Pharmacoepidemiology and drug safety, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

10 authors.

Mitsunori OgawaInterfaculty Initiative in Information Studies, The University of Tokyo, Tokyo, Japan.ORCID 0000-0002-7671-7396
Yoshinori TakeuchiDepartment of Data Science, School of Data Science, Association of International Arts and Sciences, Yokohama City University, Kanagawa, Japan.ORCID 0000-0001-9821-0513
Yukino IidaGraduate School of Interdisciplinary Information Studies, The University of Tokyo, Tokyo, Japan.
Masao IwagamiDepartment of Health Services Research, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.ORCID 0000-0001-7079-0640
Kohei UemuraInterfaculty Initiative in Information Studies, The University of Tokyo, Tokyo, Japan.
Sachiko OnoDepartment of Eat-loss Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Nobuaki MichihataCancer Prevention Center, Chiba Cancer Center Research Institute, Chiba, Japan.
Daisuke KoideDepartment of Biostatistics and Bioinformatics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Yutaka MatsuyamaDepartment of Biostatistics, School of Public Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Hideo YasunagaDepartment of Clinical Epidemiology & Health Economics, School of Public Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.

Funding

Japan Agency for Medical Research and Development JP21lk0201701Japan Agency for Medical Research and Development JP21nf0101636
6 · The paper itself

Abstract

purposeTo assess adverse neurological risks following influenza vaccination in older adults.

methodsUsing a linked database of healthcare administrative claims data and vaccination records from an urban city in Japan (April 1, 2014, to March 31, 2020), we conducted an observational study utilizing a self-controlled case series design. We identified individuals aged ≥ 65 years who experienced adverse neurological outcomes, defined as hospitalizations related to epilepsy, paralysis, facial paralysis, neuralgia, neuritis, optic neuritis, migraine, extrapyramidal disorders, Guillain-Barre syndrome, or narcolepsy. We used conditional Poisson regression to analyze within-subject incidence rate ratios, comparing the risk of these outcomes during risk periods following influenza vaccination (0-6 days and 7-29 days after each vaccination) with nonvaccination periods. Our analysis was adjusted for age and season groups as time-varying covariates.

resultsWe enrolled 3283 eligible individuals (men: 1643; mean [standard deviation] age: 76 [7.3] years). The incidence rate ratio for the outcome during the risk periods was 0.93 (95% confidence interval, 0.66-1.30) in risk period 1 (0-6 days after vaccination) and 1.14 (0.96-1.35) in risk period 2 (7-29 days after vaccination), respectively.

conclusionsWe found no evidence that the risk of adverse neurological events was increased after influenza vaccination in older adults. These results may help reassure older adults who are hesitant to receive influenza vaccination because of concerns regarding adverse neurological outcomes.

Indexed as

Influenza, HumanInfluenza VaccinesAgedAged, 80 and overDatabases, FactualFemaleHospitalizationHumansIncidenceJapanMaleNervous System DiseasesVaccinationInfluenza Vaccinesneurologyobservational studypharmacoepidemiologyself‐controlled study designvaccine safety

Identifiers

PMID39777941
PMCPMC11706699

What OpenQuestion holds

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LicenceCC BY-NC
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Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.