Received Jan 2, 2026
| Type | Name | Manufacturer | Dose | Lot | Route / Site |
|---|---|---|---|---|---|
| FLUX | INFLUENZA (SEASONAL) (NO BRAND NAME) | UNKNOWN MANUFACTURER | UNK | No batch number | — |
Myopathy; This literature report (initial receipt: 23-Dec-2025), concerns a patient with unknown age/gender who received influenza immunization. The Vaccine Adverse Event Reporting System database was reviewed. The reporting rate of myopathy, myositis, and rhabdomyolysis after Pfizer-BioNTech COVID-19 vaccination was compared to those after influenza, human papillomavirus (HPV), and meningococcal vaccinations in 3 periods: pre-COVID-19 (Oct-2018-Aug-2019), pre-vaccine (Jan-2020-Nov-2020), and vaccine (Dec-2020-Oct-2021). Six weeks after vaccination was defined as the risk period of probable cause-effect relationship. During the vaccine period, 34, 1, 1, and 2 cases of myopathy were reported after COVID-19, influenza, HPV, and meningococcal vaccinations, respectively. During the vaccine period, the patient experienced myopathy after influenza vaccination [Influenza vaccine: trade name, manufacturer and lot number not reported - to be requested upon follow up, anatomical location: Unknown]. Author's comment: There is no significant increase in cases of myopathy with COVID-19 vaccinations in the paediatric population compared to that of the general population. However, the unbalanced distribution of myopathy within the first 6 weeks suggests some myopathy cases are temporally associated with COVID-19 vaccination. Due to limitations in passive surveillance, further controlled studies are warranted to understand the myopathy risk after COVID-19 vaccination.; Reporter's Comments: Due to the spontaneous nature of the case, it is considered related for reporting purposes. Plausible temporal relationship (after influenza vaccination).
Comments: None