Flu Vaccine for Seasonal Influenza

Age: 18 - 65

Sex: Any

Trial Phase: Phase 4

Sponsor: Tal Einav

Disqualifiers: HIV, Hepatitis B, Hepatitis C, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: 6

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to understand how different timings of flu vaccinations affect immunity. Participants will receive the 2023 flu vaccine in May-June 2024 and the 2024 vaccine in September-October 2024. The goal is to determine if receiving the earlier vaccine enhances the body's response to the next season's shot. It suits individuals who haven't had a flu shot in the past year and plan to get their flu vaccine at the La Jolla Institute for Immunology. As a Phase 4 trial, this research focuses on understanding how the already FDA-approved flu vaccine can benefit more patients.

Do I need to stop my current medications to join the trial?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What is the safety track record for the Influenza Fluzone vaccine?

Research has shown that the Fluzone flu vaccine is generally safe. Most people experience only mild side effects, such as pain at the injection site, headaches, and sore muscles, which typically resolve within three days.

Studies have found no serious side effects, so the vaccine is considered safe for most individuals. However, anyone who has had a severe allergic reaction to this vaccine before should not receive it again.

Overall, the Fluzone vaccine is widely used and has a strong safety record for flu protection. ^{1 2 3 4 5}

Why are researchers enthusiastic about this study treatment?

Researchers are excited about the influenza Fluzone vaccine trial because it evaluates a unique vaccination schedule aimed at enhancing immunity against seasonal flu. Unlike the standard annual flu shot given before the flu season starts, this approach involves administering the 2023 vaccine in late spring and the 2024 vaccine in early fall. This staggered timing could potentially boost the immune response by exposing the immune system to the virus more frequently, possibly providing better protection as the flu season progresses. This strategy could lead to a more robust and sustained defense against influenza, offering improved protection compared to the traditional once-a-year vaccination.

What is the effectiveness track record for the influenza vaccine?

Research shows that the Fluzone flu vaccine effectively prevents the flu. Studies have found that these vaccines can lower the risk of flu by about 48% to 67% in adults. As a result, flu shots help many people avoid illness and reduce the chance of hospitalization due to the flu. Overall, vaccination reliably lowers the risk of catching the flu and its complications. ^{6 7 8 9 10}

Who Is on the Research Team?

Tal Einav, PhD

Principal Investigator

La Jolla Institute for Immunology

Are You a Good Fit for This Trial?

This trial is for individuals who are interested in helping to compare the effectiveness of different seasonal flu vaccines. There aren't specific inclusion or exclusion criteria provided, but typically participants should be healthy, not have allergies to vaccine components, and must not have received the current season's flu vaccine.

Inclusion Criteria

Ability to provide signed informed consent

Weigh at least 85 pounds for whole blood draw

I plan to get the flu shot at the La Jolla Institute for Immunology.

Exclusion Criteria

I am infected with HIV, hepatitis B, or hepatitis C.

Received an influenza vaccine in the past year

Has ever had Guillain-Barré syndrome

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Vaccination Phase 1

Participants receive the 2023 influenza vaccine between May-June 2024

2 months

3 visits (in-person) for blood draws at Day 0, 30, and 90 post-vaccination

Vaccination Phase 2

Participants receive the 2024 influenza vaccine in September-October 2024

2 months

3 visits (in-person) for blood draws at Day 0, 30, and 90 post-vaccination

Follow-up

Participants are monitored for safety and effectiveness after the second vaccination

3 months

What Are the Treatments Tested in This Trial?

Interventions

• Influenza Fluzone vaccine

Trial Overview The study aims to understand how effective the late-season administration of the 2023 influenza vaccine is compared to both its standard timing earlier in fall 2023 and next season's (2024) formulation given at standard times.

How Is the Trial Designed?

Group I: Late season influenza vaccine Experimental Treatment 1 Intervention

Every participant receives the 2023 influenza vaccine between May-June 2024, and then the 2024 influenza vaccine in September-October 2024. Blood draws are taken at Day 0, 30, and 90 post-vaccination.

Who Is Running the Clinical Trial?

Tal Einav

Lead Sponsor

Trials

1

Recruited

20+

La Jolla Institute for Immunology

Lead Sponsor

Trials

1

Recruited

20+

Citations

1. cdc.gov cdc.gov/flu-vaccines-work/php/effectiveness-studies/index.html

CDC Seasonal Flu Vaccine Effectiveness Studies Tables showing preliminary flu vaccine effectiveness data for the 2023-2024 season. ... Learn about flu vaccine effectiveness estimates from past ...

2. medrxiv.org medrxiv.org/content/10.1101/2025.01.30.25321421v3

Effectiveness of the Influenza Vaccine During the 2024- ... This study found that influenza vaccination of working-aged adults was associated with a higher risk of influenza during the 2024-2025 respiratory viral season.

3. cdc.gov cdc.gov/mmwr/volumes/74/wr/mm7406a2.htm

Interim Estimates of 2024–2025 Seasonal Influenza ... Effectiveness against influenza A(H3N2) was 51% (IVY) against influenza-associated hospitalization but was not statistically significant in the ...

4. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC3495721/

Effectiveness and harms of seasonal and pandemic ... Most seasonal influenza vaccines showed statistically significant efficacy/effectiveness, which was acceptable or high for laboratory-confirmed cases.

5. nejm.org nejm.org/doi/full/10.1056/NEJMsa2514268

Updated Evidence for Covid-19, RSV, and Influenza ... Influenza vaccination had a pooled vaccine effectiveness of 48% (95% CI, 39 to 55) in adults between the ages of 18 and 64 years and 67% (95% CI ...

6. cdc.gov cdc.gov/flu/vaccine-types/flu-zone.html

Fluzone High-Dose Seasonal Influenza Vaccine Safety of Fluzone High-Dose vaccine. Some side effects were reported more frequently after vaccination with trivalent Fluzone High-Dose vaccine ...

7. fda.gov fda.gov/media/119856/download

Fluzone Quadrivalent Fluzone Quadrivalent is a vaccine that helps protect against influenza illness (flu). Fluzone Quadrivalent is for people who are 6 months of age and older.

8. pro.campus.sanofi pro.campus.sanofi/us/products/sanofiflu

Trivalent Influenza Vaccines for Influenza Type A and B Important Safety Information​​ Fluzone and Fluzone High-Dose should not be administered to anyone who has had a severe allergic reaction after previous dose of ...

9. ausvaxsafety.org.au ausvaxsafety.org.au/influenza-vaccines/influenza-vaccine-safety-data-60-years-and-older-adjuvanted-or-high-dose-vaccine

60 years and older (adjuvanted or high-dose vaccine) Data on this page show the responses of individuals aged 60 years and older who received an adjuvanted or high-dose influenza vaccine in 2025.

10. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC5861790/

Influenza vaccines: Evaluation of the safety profile - PMC The most common adverse reactions were pain at the injection site, headache and myalgia, all of which disappeared within 3 days of vaccination. No serious AE ...