Trial Outcomes & Findings for Study on a High-Dose Quadrivalent Influenza Vaccine Compared With Standard-Dose Quadrivalent Influenza Vaccine in Children 6 Months Through 35 Months of Age (NCT NCT04544267)

NCT ID: NCT04544267

Last Updated: 2025-12-24

Results Overview

Laboratory-confirmed influenza was a positive influenza result on either polymerase chain reaction (PCR) or viral culture. An influenza-like illness (ILI) was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches).

• Recruitment status: TERMINATED
• Study phase: PHASE3
• Target enrollment: 100 participants
• Primary outcome timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days
• Results posted on: 2025-12-24

Participant Flow

The sentinel safety cohort of the study was conducted at 10 centers from 15 September 2020 to 10 May 2021.

The sentinel safety cohort of 100 participants were enrolled in the study. This study was prematurely terminated following a global shift in the influenza vaccine composition from quadrivalent to trivalent formulation for 2024-2025 season. Hence, main efficacy cohort was not conducted, and the safety analysis of the sentinel cohort was presented.

Participant milestones

Measure	Quadrivalent Influenza Vaccine (Split Virion, Inactivated) High-Dose Participants who were previously vaccinated against influenza received 1 dose of quadrivalent influenza vaccine (split virion, inactivated) high-dose (QIV-HD) intramuscular (IM) injection on Day 0. Participants who were not previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0 and 1 dose on Day 28.
Overall Study STARTED	100
Overall Study COMPLETED	100
Overall Study NOT COMPLETED	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Study on a High-Dose Quadrivalent Influenza Vaccine Compared With Standard-Dose Quadrivalent Influenza Vaccine in Children 6 Months Through 35 Months of Age

Baseline characteristics by cohort

Measure	Quadrivalent Influenza Vaccine (Split Virion, Inactivated) High-Dose n=100 Participants Participants who were previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0. Participants who were not previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0 and 1 dose on Day 28.
Age, Continuous	1.7 years STANDARD_DEVIATION 0.43 • n=30 Participants
Sex: Female, Male Female	54 Participants n=30 Participants
Sex: Female, Male Male	46 Participants n=30 Participants
Race/Ethnicity, Customized American Indian or Alaska Native	1 Participants n=30 Participants
Race/Ethnicity, Customized Black or African American	20 Participants n=30 Participants
Race/Ethnicity, Customized White	71 Participants n=30 Participants
Race/Ethnicity, Customized Mixed Origin	6 Participants n=30 Participants
Race/Ethnicity, Customized Not Reported	2 Participants n=30 Participants

PRIMARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Laboratory-confirmed influenza was a positive influenza result on either polymerase chain reaction (PCR) or viral culture. An influenza-like illness (ILI) was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Laboratory-confirmed influenza was a positive influenza result on either PCR or viral culture. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Laboratory-confirmed influenza was a positive influenza result on either PCR or viral culture. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Laboratory-confirmed influenza was a positive influenza result on either PCR or viral culture. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Laboratory-confirmed influenza was a positive influenza result on either PCR or viral culture. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Laboratory-confirmed influenza was a positive influenza result on either PCR or viral culture. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches). The AOM was based on clinical diagnosis.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Laboratory-confirmed influenza was a positive influenza result on either PCR or viral culture. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches). The AOM was based on clinical diagnosis.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Laboratory-confirmed influenza was a positive influenza result on either PCR or viral culture. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches). The ALRI was based on a clinical and/or x-ray diagnosis.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Laboratory-confirmed influenza was a positive influenza result on either PCR or viral culture. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches). The ALRI was based on a clinical and/or x-ray diagnosis.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

The PCR-confirmed influenza was a positive influenza result on PCR. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Culture-confirmed influenza was a positive influenza result on viral culture. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

The PCR-confirmed influenza was a positive influenza result on PCR. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Culture-confirmed influenza was a positive influenza result on viral culture. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Laboratory-confirmed influenza was a positive influenza result on either PCR or viral culture. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: From 14 days after the first vaccine administration up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 196 days

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Laboratory-confirmed influenza was a positive influenza result on either PCR or viral culture. An ILI was occurrence of fever concurrently with at least 1 of the following symptoms: cough, wheezing, difficulty breathing, nasal congestion, rhinorrhea, pharyngitis (sore throat), otitis, vomiting, diarrhea, shivering (chills), fatigue (tiredness), headache, or myalgia (muscle aches).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Days 0 and 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Antibody titers were measured by hemagglutination inhibition (HAI) assay.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Days 0 and 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Seroconversion for participants with a pre-vaccination titer <10 [1/dilution (dil)]: Post-injection titer >=40 (1/dil) on 28 days after the last vaccination or significant increase. Seroconversion for participants with a pre-vaccination titer >=10 (1/dil): >=4-fold increase from pre- to post-injection titer on 28 days after the last vaccination. Antibody titers were measured by HAI assay.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Days 0 and 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Antibody titers were measured by HAI assay. The influenza vaccine antibody titer level assessed was >=10 (1/dil).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Days 0 and 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Antibody titer ratio was calculated as individual antibody titer 28 days after the last vaccination (Day 56) divided by individual antibody titer at Day 0. Antibody titers were measured by HAI assay.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Days 0 and 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Antibody titers were measured by HAI assay. The influenza vaccine antibody titer level assessed was >=40 (1/dil).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Days 0 and 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

The antibody titers were measured by the SN method.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Antibody titer ratio was calculated as fold increase in serum SN post-vaccination relative to Day 0. Antibody titers were measured by the SN method.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Antibody titers were measured by the SN method. The SN antibody titer levels assessed were >=20 (1/dil), >=40 (1/dil) and >=80 (1/dil).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Increase of titer levels >=2 and >=4 were assessed. Antibody titers were measured by the SN method.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Days 0 and 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Detectable antibody titers were >=10 (1/dil). Antibody titers were measured by the SN method.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Days 0 and 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Antibody titers were measured by enzyme-linked lectin assay.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Antibody titer ratio was calculated as fold increase in anti-NA antibodies post-vaccination relative to Day 0. Antibody titers were measured by enzyme-linked lectin assay.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Antibody titers were measured by enzyme-linked lectin assay. Anti-NA antibody titer levels assessed were >=20 (1/dil), >=40 (1/dil) and >=80 (1/dil).

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Day 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Increase of titer levels >=2 and >=4 were assessed. Antibody titers were measured by enzyme-linked lectin assay.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Days 0 and 56

Population: The main efficacy cohort was not conducted due to shift in the global influenza vaccine guidelines. Hence, no analysis was performed.

Detectable antibody titers were >=10 (1/dil). Antibody titers were measured by enzyme-linked lectin assay.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Within 30 minutes after each vaccine administration (vaccines administered at Days 0 and 28)

Population: Expanded safety analysis set included participants who received at least 1 dose of the study vaccine in the sentinel safety cohort.

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study vaccine, whether or not considered related to the study vaccine. Immediate events were recorded to capture medically relevant unsolicited systemic AEs which occurred within the first 30 minutes after vaccination. An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, that is, pre-listed in the case report form in terms of diagnosis and onset window post-vaccination.

Outcome measures

Measure	Quadrivalent Influenza Vaccine (Split Virion, Inactivated) High-Dose n=100 Participants Participants who were previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0. Participants who were not previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0 and 1 dose on Day 28.
Number of Participants With Unsolicited Systemic Adverse Events (AEs) After Each Vaccine Dose Administration	0 Participants

SECONDARY outcome

Timeframe: Within 7 days after each vaccine administration (vaccines administered at Days 0 and 28)

Population: Expanded safety analysis set included participants who received at least 1 dose of the study vaccine in the sentinel safety cohort.

A solicited reaction was an "expected" adverse reaction (AR) (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and case report form, and were considered to be related to the study vaccine administered. An injection site reaction was an AR at and around the injection site of the study vaccine.

Outcome measures

Measure	Quadrivalent Influenza Vaccine (Split Virion, Inactivated) High-Dose n=100 Participants Participants who were previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0. Participants who were not previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0 and 1 dose on Day 28.
Number of Participants With Solicited Injection Site Reactions After Each Vaccine Dose Administration	51 Participants

SECONDARY outcome

Timeframe: Within 7 days after each vaccine administration (vaccines administered at Days 0 and 28)

Population: Expanded safety analysis set included participants who received at least 1 dose of the study vaccine in the sentinel safety cohort.

A solicited reaction was an "expected" AR (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and case report form, and were considered to be related to the study vaccine administered. Systemic AR were all ARs that were not injection site reactions.

Outcome measures

Measure	Quadrivalent Influenza Vaccine (Split Virion, Inactivated) High-Dose n=100 Participants Participants who were previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0. Participants who were not previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0 and 1 dose on Day 28.
Number of Participants With Solicited Systemic Reactions After Each Vaccine Dose Administration	46 Participants

SECONDARY outcome

Timeframe: Within 28 days after each vaccine administration (vaccines administered at Days 0 and 28)

Population: Expanded safety analysis set included participants who received at least 1 dose of the study vaccine in the sentinel safety cohort.

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study vaccine, whether or not considered related to the study vaccine. An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, that is, pre-listed in the case report form in terms of diagnosis and onset window post-vaccination.

Outcome measures

Measure	Quadrivalent Influenza Vaccine (Split Virion, Inactivated) High-Dose n=100 Participants Participants who were previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0. Participants who were not previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0 and 1 dose on Day 28.
Number of Participants With Unsolicited Adverse Events After Each Vaccine Dose Administration	25 Participants

SECONDARY outcome

Timeframe: From first dose of study vaccine administration (Day 1) up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 210 days

Population: Expanded safety analysis set included participants who received at least 1 dose of the study vaccine in the sentinel safety cohort.

An SAE was defined as any AE that at any dose resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was an important medical event. An AESI (serious or non-serious) was 1 of scientific and medical concern specific to the Sponsor's study vaccine or program, for which ongoing monitoring and rapid communication by the Investigator to the Sponsor could be appropriate.

Outcome measures

Measure	Quadrivalent Influenza Vaccine (Split Virion, Inactivated) High-Dose n=100 Participants Participants who were previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0. Participants who were not previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0 and 1 dose on Day 28.
Number of Participants With Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs) SAE	1 Participants
Number of Participants With Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs) AESI	0 Participants

Adverse Events

Quadrivalent Influenza Vaccine (Split Virion, Inactivated) High-Dose

Serious events: 1 serious events

Other events: 65 other events

Deaths: 0 deaths

Serious adverse events

Measure	Quadrivalent Influenza Vaccine (Split Virion, Inactivated) High-Dose n=100 participants at risk Participants who were previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0. Participants who were not previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0 and 1 dose on Day 28.
Infections and infestations Otitis Media Acute	1.0% 1/100 • Number of events 1 • From first dose of study vaccine administration (Day 1) up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 210 days. Analysis was performed on the expanded safety analysis set.

Other adverse events

Measure	Quadrivalent Influenza Vaccine (Split Virion, Inactivated) High-Dose n=100 participants at risk Participants who were previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0. Participants who were not previously vaccinated against influenza received 1 dose of QIV-HD IM injection on Day 0 and 1 dose on Day 28.
Metabolism and nutrition disorders Decreased Appetite	22.0% 22/100 • Number of events 25 • From first dose of study vaccine administration (Day 1) up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 210 days. Analysis was performed on the expanded safety analysis set.
Psychiatric disorders Irritability	38.0% 38/100 • Number of events 50 • From first dose of study vaccine administration (Day 1) up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 210 days. Analysis was performed on the expanded safety analysis set.
Nervous system disorders Somnolence	25.0% 25/100 • Number of events 30 • From first dose of study vaccine administration (Day 1) up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 210 days. Analysis was performed on the expanded safety analysis set.
General disorders Crying	28.0% 28/100 • Number of events 35 • From first dose of study vaccine administration (Day 1) up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 210 days. Analysis was performed on the expanded safety analysis set.
General disorders Injection Site Bruising	9.0% 9/100 • Number of events 10 • From first dose of study vaccine administration (Day 1) up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 210 days. Analysis was performed on the expanded safety analysis set.
General disorders Injection Site Erythema	25.0% 25/100 • Number of events 31 • From first dose of study vaccine administration (Day 1) up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 210 days. Analysis was performed on the expanded safety analysis set.
General disorders Injection Site Induration	12.0% 12/100 • Number of events 12 • From first dose of study vaccine administration (Day 1) up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 210 days. Analysis was performed on the expanded safety analysis set.
General disorders Injection Site Pain	44.0% 44/100 • Number of events 53 • From first dose of study vaccine administration (Day 1) up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 210 days. Analysis was performed on the expanded safety analysis set.
General disorders Injection Site Swelling	12.0% 12/100 • Number of events 14 • From first dose of study vaccine administration (Day 1) up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 210 days. Analysis was performed on the expanded safety analysis set.
General disorders Pyrexia	9.0% 9/100 • Number of events 11 • From first dose of study vaccine administration (Day 1) up to 6 months after the last vaccine administration (vaccines administered at Days 0 and 28), approximately 210 days. Analysis was performed on the expanded safety analysis set.

Additional Information

Trial Transparency Team

Sanofi Pasteur

Phone: 800-633-1610

Email: Contact-US@sanofi.com

Results disclosure agreements

• Principal investigator is a sponsor employee The Sponsor must have the opportunity to review at least 60 days prior to submission for publication or presentation. If review indicates that potentially patentable subject matter would be disclosed, publication or public disclosure may be delayed for a maximum of an additional 60 days to allow for filing the necessary patent applications.
• Publication restrictions are in place

Restriction type: OTHER