Efluelda Adverse Reactions

Clinical Trials Experience: Because clinical trials are conducted under widely varying conditions, adverse event rates observed in the clinical trial(s) of a vaccine cannot be directly compared to rates in the clinical trial(s) of another vaccine and may not reflect the rates observed in practice. One clinical study has evaluated the safety of Efluelda.
Study 1 (NCT03282240, see https://clinicaltrials.gov) was a randomized, active-controlled, modified double-blind pre-licensure trial conducted in the U.S. The study compared the safety and immunogenicity of Efluelda to those of Fluzone High-Dose (trivalent formulation). The safety analysis set included 1777 Efluelda recipients, 443 Fluzone High-Dose recipients, and 450 investigational Fluzone High-Dose containing the alternate B influenza strain recipients.
The most common reactions occurring after Efluelda administration were injection-site pain (41.3%), myalgia (22.7%), headache (14.4%), and malaise (13.2%). Onset usually occurred within the first 3 days after vaccination. The majority of solicited reactions resolved within three days of vaccination.
Table 5 displays solicited adverse reactions for Efluelda compared to Fluzone High-Dose reported within 7 days after vaccination and collected using standardized diary cards. (See Table 5.)

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Based on data from Fluzone High-Dose, solicited injection site reactions and systemic adverse reactions were slightly more frequent after vaccination with Fluzone High-Dose compared to a standard-dose vaccine.
Unsolicited non-serious adverse events were reported in 279 (15.7%) recipients in the Efluelda group and 140 (15.7%) recipients in the Fluzone High-Dose group. The most commonly reported unsolicited adverse event was cough.
Within 180 days post-vaccination, 80 (4.5%) Efluelda recipients and 48 (5.4%) Fluzone High-Dose recipients experienced a serious adverse event (SAE). None of the SAEs were assessed as related to the study vaccines.
Postmarketing Experience: The following additional adverse events have been spontaneously reported during the postmarketing use of Fluzone High-Dose, Fluzone, or Fluzone Quadrivalent and may occur in people receiving Efluelda. Because these events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to vaccine exposure. Adverse events were included based on one or more of the following factors: severity, frequency of reporting, or strength of evidence for a causal relationship to Fluzone High-Dose, Fluzone, or Fluzone Quadrivalent.
Blood and Lymphatic System Disorders: Thrombocytopenia, lymphadenopathy.
Immune System Disorders: Anaphylaxis, other allergic/hypersensitivity reactions (including urticaria, angioedema).
Eye Disorders: Ocular hyperemia.
Nervous System Disorders: Guillain-Barré syndrome (GBS), convulsions, febrile convulsions, myelitis (including encephalomyelitis and transverse myelitis), facial palsy (Bell's palsy), optic neuritis/neuropathy, brachial neuritis, syncope (shortly after vaccination), dizziness, paresthesia.
Vascular Disorders: Vasculitis, vasodilatation.
Respiratory, Thoracic and Mediastinal Disorders: Dyspnea, cough, wheezing, throat tightness, oropharyngeal pain, and rhinorrhea.
Gastrointestinal Disorders: Vomiting.
Skin and Subcutaneous Tissue Disorders: Stevens-Johnson syndrome.
General Disorders and Administration Site Conditions: Pruritus, asthenia/fatigue, chest pain, chills.