FluMist (influenza vaccine, live, intranasal) / AstraZeneca - LARVOL DELTA

Mist-ical memory: The airway defenses induced by FluMist vaccination in adults. (PubMed, Sci Immunol) - "Longitudinal nasopharyngeal swabs sample and reveal upper airway humoral memory generated after intranasal FluMist vaccination."

Journal

SAFE (Self-Administration of Flumist to ImprovE Uptake: A Household-Based Cluster Randomized Trial) (clinicaltrials.gov) - P4 | N=966 | Not yet recruiting | Sponsor: McMaster University

New P4 trial • Infectious Disease • Influenza • Respiratory Diseases

MOSAIC: How Healthy Adults Respond to the Nasal Flu Vaccine (clinicaltrials.gov) - P4 | N=20 | Not yet recruiting | Sponsor: University of Alabama at Birmingham

New P4 trial • Infectious Disease • Influenza • Respiratory Diseases

SmokeyFlu: Woodsmoke Exposure, Influenza Infection, and Nasal Immunity (clinicaltrials.gov) - P4 | N=112 | Recruiting | Sponsor: University of North Carolina, Chapel Hill | Suspended ➔ Recruiting

Enrollment open • Infectious Disease • Influenza • Otorhinolaryngology • Respiratory Diseases

Assessment of hemagglutinin-inhibition activity following influenza vaccination during the 2022-2023, 2023-2024, and 2024-2025 seasons. (PubMed, PLoS One) - "In this three-season (2022-2023-2024-2025) study, 1,328 participants aged 9-89 years received one of six vaccine types (Fluzone standard dose (SD) or high dose (HD), Fluad, Flucelvax, Flublok, Flumist). Participants vaccinated with Flumist had low or no measurable serum HAI activity. Overall, the elicitation of vaccine induced immune responses is strongly influenced by vaccine formulation, age and immune history of the participant."

Journal • Infectious Disease • Influenza • Respiratory Diseases

Local B cell immunity and durable memory after live-attenuated influenza intranasal vaccination of humans. (PubMed, Sci Transl Med) - "An intranasally administered, live-attenuated influenza vaccine designed to stimulate mucosal immunity, FluMist, is the sole intranasal vaccine approved in the United States. Thus, despite minimal immune responses detected in circulation, adults vaccinated with the live-attenuated influenza vaccine generate substantial local antigen-specific memory B cell responses. These findings have implications for improving influenza vaccines and for mucosal vaccination against other respiratory pathogens."

Journal • Infectious Disease • Influenza • Respiratory Diseases • CD21 • CD27

VAXXAIR: Vaccine Pandemic Preparedness Through Airway Immunology Characterization (clinicaltrials.gov) - P1 | N=60 | Active, not recruiting | Sponsor: Copenhagen Respiratory Research | Not yet recruiting ➔ Active, not recruiting

Enrollment closed • Infectious Disease • Influenza • Respiratory Diseases • CD4 • CD8

Responses to Live Attenuated Influenza Virus (LAIV) in Chronic Obstructive Pulmonary Disease (COPD) (clinicaltrials.gov) - P1 | N=24 | Completed | Sponsor: University of North Carolina, Chapel Hill | Recruiting ➔ Completed | N=40 ➔ 24

Enrollment change • Trial completion • Chronic Obstructive Pulmonary Disease • Immunology • Infectious Disease • Influenza • Pulmonary Disease • Respiratory Diseases

The Decline in Influenza Antibody Titers and Modifiers of Vaccine Immunity from over Ten Years of Serological Data. (PubMed, medRxiv) - "Not being vaccinated or receiving the live-attenuated FluMist vaccine in one year significantly enhanced the response to inactivated vaccines in 45% or 68% of cohorts, respectively, whereas antigen dose and adjuvants had modest impact. These findings identify vaccine timing and seasonal context as underrecognized drivers of immunogenicity and provide actionable insights for optimizing influenza vaccination strategies."

Journal • Infectious Disease • Influenza • Respiratory Diseases

Integrated analysis of humoral and memory B-cell responses reveals distinct immune landscapes shaped by influenza vaccine platforms. (PubMed, NPJ Vaccines) - "This study employed an integrated analysis of humoral and MBC responses elicited by three licensed influenza vaccines: inactivated Fluzone standard dose (FluZ), recombinant protein-based FluBlok (FluB), and live-attenuated intranasal FluMist (FluM). Notably, FluM-vaccinees showed greater inter-correlation among multiple MBC subsets, particularly for H3. These findings uncover distinct platform-specific immune landscape and demonstrate that FluB induces superior MBC responses, providing a framework for designing next-generation vaccines."

Journal • Infectious Disease • Influenza • Respiratory Diseases

Replication in human cells supersedes serum antigenic match for the in vivo efficacy of an A/H1N1pdm09 LAIV virus. (PubMed, NPJ Vaccines) - "For FluMist®/Fluenz live attenuated influenza vaccine (LAIV), efficient virus replication in human nasal epithelial cells (hNEC) is an important factor in vaccine effectiveness (VE). LAIVH1.opt was also found to be more immunogenic in ferrets than LAIVH1.par, generating superior anti-HA and anti-NA antibody responses. We conclude that efficient virus replication can supersede antigenic match for high LAIV efficacy."

Journal • Preclinical • Infectious Disease • Influenza • Respiratory Diseases

Live-attenuated influenza virus vaccine strain with an engineered temperature-sensitive and genetically stable viral polymerase variant. (PubMed, J Virol) - "The only licensed live-attenuated influenza vaccine that has been proven safe and effective is FluMist. In this study, we isolated an attenuated influenza mutant virus with a Lys471 single amino acid substitution in PB1, which displayed a temperature-sensitive and a low-pathogenicity phenotype. By applying the PB1-Lys471 substitution to the vaccine mother strain or the circulating influenza virus using reverse genetic technology, a high-performance and safe live-attenuated vaccine carrying the viral antigens of the vaccine-targeted strain can be developed."

Journal • Infectious Disease • Influenza • Respiratory Diseases

PRISM: Revealing Protective Immunity to Influenza Using Systems Immunology (clinicaltrials.gov) - P4 | N=51 | Completed | Sponsor: Emory University | Recruiting ➔ Completed | Trial completion date: Feb 2027 ➔ Apr 2025 | Trial primary completion date: Feb 2027 ➔ Apr 2025

Trial completion • Trial completion date • Trial primary completion date • Infectious Disease • Influenza • Respiratory Diseases

Ingredient Transparency Required for Identifying Alpha-gal Safe Vaccines (ACAAI 2025) - "For influenza, Flumist should not be recommended, as it contains gelatin. Manufacturers are encouraged to embrace ingredient transparency and collaborate with independent portals to facilitate selection of alpha-gal safe vaccines. This case is one of over 5000 AGS related medication inquiries received by Pill Clarity in 2025."

Infectious Disease • Influenza • Novel Coronavirus Disease • Respiratory Diseases

Antiviral drugs for seasonal influenza for 2025-2026. (PubMed, Med Lett Drugs Ther) - No abstract available

Journal • Infectious Disease • Influenza • Respiratory Diseases

Influenza vaccines for 2025-2026. (PubMed, Med Lett Drugs Ther) - No abstract available

Journal • Hepatitis B • Infectious Disease • Influenza • Novel Coronavirus Disease • Respiratory Diseases • Respiratory Syncytial Virus Infections

Pharmacovigilance-based 12-year post-marketing safety analysis of quadrivalent influenza vaccines in children: a VAERS surveillance study. (PubMed, Front Pediatr) - "We conducted a comprehensive 12-year pharmacovigilance analysis utilizing data from the Vaccine Adverse Event Reporting System (VAERS) for individuals under 18 years receiving six FDA-approved QIVs between 2013 and 2024, representing three distinct platforms: four egg-based inactivated vaccines (Afluria, Fluarix, FluLaval, Fluzone), one cell culture-based inactivated vaccine (Flucelvax), and one live-attenuated intranasal vaccine (FluMist). This pharmacovigilance analysis demonstrates generally favorable safety profiles for pediatric QIVs, with cell culture formulations showing superior safety characteristics. The extremely low absolute risk of Guillain-Barré syndrome supports continued routine pediatric influenza vaccination while highlighting the importance of platform-specific safety monitoring."

Adverse events • Journal • P4 data • Infectious Disease • Influenza • Novel Coronavirus Disease • Pediatrics • Respiratory Diseases

EVax-3: Characterizing the Human Airway Immune Response to FluMist Vaccination (clinicaltrials.gov) - P4 | N=30 | Recruiting | Sponsor: Washington University School of Medicine

New P4 trial • Infectious Disease • Influenza • Respiratory Diseases

Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices - United States, 2025-26 Influenza Season. (PubMed, MMWR Morb Mortal Wkly Rep) - "Updates for the 2025-26 season include 1) antigenic composition of 2025-26 U.S. seasonal influenza vaccines, 2) Food and Drug Administration (FDA) approval of FluMist (LAIV3) for self-administration or caregiver administration, 3) FDA approval of a change in age indication for Flublok (RIV3) from ≥18 years to ≥9 years, and 4) a new ACIP recommendation that children aged ≤18 years, pregnant women, and all adults receive seasonal influenza vaccines only in single-dose formulations that are free of thimerosal as a preservative. A comprehensive summary of recommendations, including those discussed in this report, as well as previous recommendations concerning topics not addressed in this report and that remain unchanged for the 2025-26 season, is available at Influenza; ACIP Recommendations for Vaccination. Additional background information also is available at Prevention and Control of Seasonal Influenza with Vaccines."

Clinical guideline • Journal • Infectious Disease • Influenza • Respiratory Diseases

Local B-cell immunity and durable memory following live-attenuated influenza intranasal vaccination of humans. (PubMed, bioRxiv) - "An intranasally administered, live-attenuated influenza vaccine designed to stimulate mucosal immunity, FluMist, is the sole intranasal vaccine approved in the United States. These findings have implications for improving influenza vaccines and for mucosal vaccination against other respiratory pathogens. Longitudinal nasopharyngeal sampling reveals local influenza-specific B cell responses following intranasal but not intramuscular vaccination."

Journal • Infectious Disease • Influenza • Respiratory Diseases • CD21 • CD27

Association between tick-bite history and safety of gelatin-containing vaccines: Analysis of a large database of the United States. (PubMed, Ticks Tick Borne Dis) - "Vaccines were classified into two categories: (1) gelatin-containing vaccines (live intranasal influenza [FluMist], varicella, measles/mumps/rubella [MMR], oral typhoid, rabies [RabAvert], and yellow fever vaccines [YF-VAX]) and (2) gelatin-free vaccines...While tick bites are associated with AGS, a history of tick bites is not a contraindication for most gelatin-containing vaccines, including MMR, oral typhoid, rabies, and yellow fever vaccines. Further investigations are warranted to evaluate the safety of intranasal influenza and varicella vaccines in this population."

Journal • Allergy • Immunology • Infectious Disease • Influenza • Measles • Mumps • Respiratory Diseases • Rubella • Varicella Zoster

SmokeyFlu: Woodsmoke Exposure, Influenza Infection, and Nasal Immunity (clinicaltrials.gov) - P4 | N=112 | Suspended | Sponsor: University of North Carolina, Chapel Hill | Trial completion date: Dec 2027 ➔ Dec 2028 | Initiation date: Mar 2025 ➔ Oct 2026 | Not yet recruiting ➔ Suspended | Trial primary completion date: Dec 2027 ➔ Dec 2028

Trial completion date • Trial initiation date • Trial primary completion date • Trial suspension • Infectious Disease • Influenza • Otorhinolaryngology • Respiratory Diseases

Responses to Live Attenuated Influenza Virus (LAIV) in Chronic Obstructive Pulmonary Disease (COPD) (clinicaltrials.gov) - P1 | N=40 | Recruiting | Sponsor: University of North Carolina, Chapel Hill | Trial completion date: Mar 2025 ➔ Mar 2026 | Trial primary completion date: Mar 2025 ➔ Mar 2026

Trial completion date • Trial primary completion date • Chronic Obstructive Pulmonary Disease • Immunology • Infectious Disease • Influenza • Pulmonary Disease • Respiratory Diseases

Disruption of the commensal microbiota impairs the maintenance of antigen specific memory T cells. (IMMUNOLOGY 2025) - "We also found that AB-treated mice failed to maintain lung tissue-resident CD4+ and CD8+ memory T cells generated by immunization with a live-attenuated influenza vaccine (FluMist). Collectively, these finds support the requirement of an intact commensal microbiota for the maintenance of CD4+ memory T cells generated upon infection and vaccination. The mechanisms mediating this effect of the commensal microbiota in memory T cell maintenance are currently under active investigation.Keywords: Cells T Cells; Infections Viral; Processes Memory; Tissues Lung Mucosa"

Clinical • Infectious Disease • Influenza • Respiratory Diseases • CD4 • CD8

Broadly active intranasal influenza vaccine with a nanocomplex particulate adjuvant targeting mast cells and toll-like receptor 9. (PubMed, J Control Release) - "Flumist is the only FDA-approved intranasal influenza vaccine. MP12W-CpG NPs provided similar protection in an influenza challenge model. This study demonstrates the potential of this novel intranasal nanocomplex for vaccination."

Journal • Immunology • Infectious Disease • Inflammation • Influenza • Respiratory Diseases • TLR9