Japan's Ministry of Health, Labour and Welfare wants to add Guillain-Barré syndrome to the list of adverse events doctors and vaccinators must report after a recombinant RS virus (RSV) vaccination. The ministry published a draft amendment to the Regulation for Enforcement of the Immunization Act on August 27, 2026, proposing that any case of the syndrome confirmed within 28 days of a shot be reported to the health minister under Article 12, Paragraph 1 of the Immunization Act.
The trigger is a package-insert change. The insert for the recombinant RSV vaccine was revised to list Guillain-Barré syndrome as a serious adverse reaction. One adverse-reaction-suspicion report tied to the vaccine showed the syndrome emerging 18 days after vaccination, and the ministry says the causal link with the vaccine could not be ruled out. Because that timing falls inside the 28-day reporting window already used for five other shots covered by Japan's routine immunization program, human papillomavirus, varicella, shingles, hepatitis B, and influenza, the ministry is extending the same window to RSV rather than setting a separate standard.
| Milestone | Date |
|---|---|
| Comment period opens | August 27, 2026 |
| Comment period closes | September 27, 2026 |
| Promulgation (planned) | Mid-November 2026 |
| Effective date | Date of promulgation |
The public comment window runs 31 days, from August 27 to September 27, 2026. Submissions must be in Japanese and can go through the e-Gov portal, a dedicated ministry email address, or post to the Ministry of Health, Labour and Welfare's Tokyo office; the ministry does not accept comments by phone. The Health and Welfare Bureau's Infectious Disease Control Department, Immunization Division is handling the file under case number 495260162. Promulgation is targeted for mid-November 2026, with the rule taking effect on the day it is promulgated, so vaccine handlers and clinics administering the RSV shot would need updated adverse-event tracking procedures in place by then.
What the packet does not show is a running count of Guillain-Barré syndrome cases tied to the vaccine beyond the single report cited, and it does not name the vaccine's manufacturer. Those gaps make this a compliance-calendar item for now, not a signal of a wider safety problem: the ministry is standardizing a reporting duty, not restricting or recalling anything.