A Phase III, multicenter, randomized, double-blind, active comparator-controlled study to evaluate the safety, tolerability, and immunogenicity of V114 compared with PCV13 in healthy infants (PNEU-PED-EU-1).

BACKGROUND: V114 (15-valent pneumococcal conjugate vaccine [PCV]) contains all serotypes in 13-valent PCV (PCV13) and additional serotypes 22F and 33F. This study evaluated safety and immunogenicity of V114 compared with PCV13 in healthy infants, and concomitant administration with DTPa-HBV-IPV/Hib and rotavirus RV1 vaccines. METHODS: V114 and PCV13 were administered in a 2+1 schedule at 2, 4, and 11-15 months of age. Adverse events (AEs) were collected on Days 1-14 following each vaccination. Serotype-specific anti-pneumococcal immunoglobulin G (IgG) was measured 30 days post-primary series (PPS), immediately prior to a toddler dose, and 30 days post-toddler dose (PTD). Primary objectives included non-inferiority of V114 to PCV13 for 13 shared serotypes and superiority of V114 to PCV13 for the two additional serotypes. RESULTS: 1184 healthy infants 42-90 days of age were randomized 1:1 to V114 (n = 591) or PCV13 (n = 593). Proportions of participants with solicited AEs and serious AEs were comparable between vaccination groups. V114 met pre-specified non-inferiority criteria for all 13 shared serotypes, based on the difference in proportions of participants with serotype-specific IgG concentrations ≥0.35 µg/mL (response rate; lower bound of two-sided 95% confidence interval [CI] >-10.0) and IgG geometric mean concentration (GMC) ratios (lower bound of two-sided 95% CI >0.5), and pre-specified superiority criteria for serotypes 22F and 33F (lower bound of two-sided 95% CI >10.0 for response rates and >2.0 for GMC ratios). Antibody responses to DTPa-HBV-IPV/Hib and RV1 vaccines met pre-specified non-inferiority criteria, based on antigen-specific response rates to DTPa-HBV-IPV/Hib and anti-rotavirus IgA geometric mean titers. CONCLUSIONS: After a 2+1 schedule, V114 elicited non-inferior immune responses to 13 shared serotypes and superior responses to the two additional serotypes compared with PCV13, with comparable safety profile. These results support the routine use of V114 in infants. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04031846; EudraCT: 2018-003787-31.

Real-world study in infants fed with an infant formula with two human milk oligosaccharides / Estudio en condiciones reales de lactantes alimentados con una fórmula infantil con dos oligosacáridos de leche humana

INTRODUCTION: human milk oligosaccharides (HMOs) are an important component of human milk supporting the development of a balanced intestinal microbiota and immune protection in breastfed infants. Randomized controlled trials (RCTs) have demonstrated that infant formulas supplemented with the HMOs 2'-fucosyllactose (2'FL) and lacto-N-neotetraose (LNnT) are safe, well-tolerated, and support normal growth. This Real-World Evidence (RWE) study aimed to evaluate growth and tolerance in infants consuming a formula supplemented with 1 g/L of 2'FL and 0.5 g/L of LNnT, and included a mixed-feeding group never studied before in RCTs. Participants and methods: this open-label, prospective study was conducted at six centers in Spain, and included healthy, exclusively breastfed infants (BF group), an exclusively formula-fed group (FF) who received a milk-based formula with 2' FL and LNnT, and a group mixed fed with both formula and human milk (MF), for 8 weeks. Co-primary outcomes were growth (anthropometry) and gastrointestinal tolerance (Infant Gastrointestinal Symptom Questionnaire, IGSQ). Secondary outcomes included formula satisfaction and adverse events (AEs). RESULTS: 159 infants completed the study (66 FF, 48 MF, and 45 BF). Mean z-scores for growth were similar between all groups and within ± 0.5 of WHO medians at week 8. Composite IGSQ scores demonstrated low GI distress in all groups, with no significant group differences at baseline, week 4, or week 8. Incidence of AEs was low overall, and comparable across groups. CONCLUSIONS: in this RWE study examining a HMO-supplemented infant formula, growth and tolerance outcomes were similar to RCT findings, supporting the effectiveness of this early feeding option

INTRODUCCIÓN: los oligosacáridos de la leche materna (HMO) contribuyen a desarrollar la inmunoprotección y la microbiota intestinal. Los ensayos aleatorizados (RCT) han demostrado que las fórmulas enriquecidas con 2'fucosilactosa (2'FL) y lacto-N-neotetraosa (LNnT) son seguras, bien toleradas y favorecen el crecimiento. El objetivo de este estudio ha sido valorar el crecimiento, la seguridad y la tolerancia digestiva en lactantes alimentados con una fórmula enriquecida con 1 g/L de 2'FL y 0,5 g/L de LNnT, con datos de la vida real (RWE), incluyendo un grupo de alimentación mixta no estudiado antes en los RCT. Participantes y métodos: estudio prospectivo abierto en seis hospitales españoles que incluyó lactantes sanos alimentados con leche materna (BF), con fórmula enriquecida en 2'FL y LNnT (FF) o con mezcla de ambas (MF), durante ocho semanas. Se valoraron el crecimiento (antropometría), la tolerancia gastrointestinal (cuestionario IGSQ) y los acontecimientos adversos. RESULTADOS: 159 lactantes completaron el estudio (66, 48 y 45, en los grupos FF, MF y BF, respectivamente). Las puntuaciones Z antropométricas a la semana 8 fueron similares entre los grupos y se hallaron dentro del rango de ± 0,5 de la normalidad. Las puntuaciones IGSQ compuestas mostraron un bajo malestar digestivo, sin diferencias significativas entre los grupos, al inicio y en las semanas 4 y 8. La incidencia de eventos adversos fue baja y comparable entre los grupos. CONCLUSIONES: en este estudio RWE que evaluó una fórmula para lactantes enriquecida en HMO, los resultados sobre el crecimiento, la tolerancia y la seguridad fueron similares a los obtenidos en los RCT, respaldando su eficacia como alimentación temprana opcional

Real-world study in infants fed with an infant formula with two human milk oligosaccharides.

Introduction: Introduction: human milk oligosaccharides (HMOs) are an important component of human milk supporting the development of a balanced intestinal microbiota and immune protection in breastfed infants. Randomized controlled trials (RCTs) have demonstrated that infant formulas supplemented with the HMOs 2'-fucosyllactose (2'FL) and lacto-N-neotetraose (LNnT) are safe, well-tolerated, and support normal growth. This Real-World Evidence (RWE) study aimed to evaluate growth and tolerance in infants consuming a formula supplemented with 1 g/L of 2'FL and 0.5 g/L of LNnT, and included a mixed-feeding group never studied before in RCTs. Participants and methods: this open-label, prospective study was conducted at six centers in Spain, and included healthy, exclusively breastfed infants (BF group), an exclusively formula-fed group (FF) who received a milk-based formula with 2' FL and LNnT, and a group mixed fed with both formula and human milk (MF), for 8 weeks. Co-primary outcomes were growth (anthropometry) and gastrointestinal tolerance (Infant Gastrointestinal Symptom Questionnaire, IGSQ). Secondary outcomes included formula satisfaction and adverse events (AEs). Results: 159 infants completed the study (66 FF, 48 MF, and 45 BF). Mean z-scores for growth were similar between all groups and within ± 0.5 of WHO medians at week 8. Composite IGSQ scores demonstrated low GI distress in all groups, with no significant group differences at baseline, week 4, or week 8. Incidence of AEs was low overall, and comparable across groups. Conclusions: in this RWE study examining a HMO-supplemented infant formula, growth and tolerance outcomes were similar to RCT findings, supporting the effectiveness of this early feeding option.

Introducción: Introducción: los oligosacáridos de la leche materna (HMO) contribuyen a desarrollar la inmunoprotección y la microbiota intestinal. Los ensayos aleatorizados (RCT) han demostrado que las fórmulas enriquecidas con 2'fucosilactosa (2'FL) y lacto-N-neotetraosa (LNnT) son seguras, bien toleradas y favorecen el crecimiento. El objetivo de este estudio ha sido valorar el crecimiento, la seguridad y la tolerancia digestiva en lactantes alimentados con una fórmula enriquecida con 1 g/L de 2'FL y 0,5 g/L de LNnT, con datos de la vida real (RWE), incluyendo un grupo de alimentación mixta no estudiado antes en los RCT. Participantes y métodos: estudio prospectivo abierto en seis hospitales españoles que incluyó lactantes sanos alimentados con leche materna (BF), con fórmula enriquecida en 2'FL y LNnT (FF) o con mezcla de ambas (MF), durante ocho semanas. Se valoraron el crecimiento (antropometría), la tolerancia gastrointestinal (cuestionario IGSQ) y los acontecimientos adversos. Resultados: 159 lactantes completaron el estudio (66, 48 y 45, en los grupos FF, MF y BF, respectivamente). Las puntuaciones Z antropométricas a la semana 8 fueron similares entre los grupos y se hallaron dentro del rango de ± 0,5 de la normalidad. Las puntuaciones IGSQ compuestas mostraron un bajo malestar digestivo, sin diferencias significativas entre los grupos, al inicio y en las semanas 4 y 8. La incidencia de eventos adversos fue baja y comparable entre los grupos. Conclusiones: en este estudio RWE que evaluó una fórmula para lactantes enriquecida en HMO, los resultados sobre el crecimiento, la tolerancia y la seguridad fueron similares a los obtenidos en los RCT, respaldando su eficacia como alimentación temprana opcional.

Impact of tetanus-diphtheria-acellular pertussis immunization during pregnancy on subsequent infant immunization seroresponses: follow-up from a large randomized placebo-controlled trial.

BACKGROUND: Pertussis immunization during pregnancy results in high pertussis antibody concentrations in young infants but may interfere with infant immune responses to post-natal immunization. METHODS: This phase IV, multi-country, open-label study assessed the immunogenicity and safety of infant primary vaccination with DTaP-HepB-IPV/Hib and 13-valent pneumococcal conjugate vaccine (PCV13). Enrolled infants (6-14 weeks old) were born to mothers who were randomized to receive reduced-antigen-content diphtheria-tetanus-three-component acellular pertussis vaccine (Tdap group) or placebo (control group) during pregnancy (270/7-366/7 weeks' gestation) with crossover immunization postpartum. All infants received 2 or 3 DTaP-HepB-IPV/Hib and PCV13 doses according to national schedules. Immunogenicity was assessed in infants pre- and 1 month post-primary vaccination. The primary objective was to assess seroprotection/vaccine response rates for DTaP-HepB-IPV/Hib antigens 1 month post-primary vaccination. RESULTS: 601 infants (Tdap group: 296; control group: 305) were vaccinated. One month post-priming, seroprotection rates were 100% (diphtheria; tetanus), ≥98.5% (hepatitis B), ≥95.9% (polio) and ≥94.5% (Hib) in both groups. Vaccine response rates for pertussis antigens were significantly lower in infants whose mothers received pregnancy Tdap (37.5-77.1%) versus placebo (90.0-99.2%). Solicited and unsolicited adverse event rates were similar between groups. Serious adverse events occurred in 2.4% (Tdap group) and 5.6% (control group) of infants, none were vaccination-related. CONCLUSIONS: Pertussis antibodies transferred during pregnancy may decrease the risk of pertussis infection in the first months of life but interfere with the infant's ability to produce pertussis antibodies, the clinical significance of which remains unknown. Safety and reactogenicity results were consistent with previous experience. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT02422264.

Immunogenicity and safety of 11- and 12-valent pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccines (11vPHiD-CV, 12vPHiD-CV) in infants: Results from a phase II, randomised, multicentre study.

BACKGROUND: We assessed 2 investigational 11- and 12-valent vaccines, containing capsular polysaccharides of 10 serotypes as in the pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) and CRM197-conjugated capsular polysaccharides of serotypes 19A (11-valent) or 19A and 6A (12-valent). METHODS: In this phase II, partially-blind, multicentre study (NCT01204658), healthy infants were randomised (1:1:1:1) to receive 11vPHiD-CV, 12vPHiD-CV, PHiD-CV, or 13-valent CRM197-conjugate pneumococcal vaccine (PCV13), at 2, 3, and 4 (primary series), and 12-15 months of age (booster dose), co-administered with DTPa-HBV-IPV/Hib. Confirmatory objectives assessed non-inferiority of investigational vaccines to comparators (PHiD-CV for common serotypes; PCV13 for 19A and 6A), in terms of percentage of infants with pneumococcal antibody concentrations ≥0.2 µg/mL and antibody geometric mean concentrations, post-primary vaccination. Reactogenicity and safety were assessed. RESULTS: 951 children received ≥1 primary dose, 919 a booster dose. Pre-defined immunological non-inferiority criteria were met simultaneously for 9/11 11vPHiD-CV serotypes (all except 23F and 19A) and 10/12 12vPHiD-CV serotypes (all except 19A and 6A); thus, non-inferiority objectives were reached. For each PHiD-CV serotype, percentages of children with antibody concentrations ≥0.2 µg/mL were ≥96.7% post-primary (except 6B [≥75.2%] and 23F [≥81.1%]), and ≥98.1% post-booster vaccination. For each PHiD-CV serotype except serotype 1, ≥81.0% and ≥93.9% of children had opsonophagocytic activity titres ≥8, post-primary and booster vaccination. AEs incidence was similar across all groups. SAEs were reported for 117 children (29 in the 11vPHiD-CV group, 26 in the 12vPHiD-CV group, 38 in the PHiD-CV group and 24 in the PCV13 group); 4 SAEs were considered vaccination-related. No fatal events were recorded. CONCLUSION: Addition of 19A and 6A CRM197-conjugates did not alter immunogenicity of the PHiD-CV conjugates; for both investigational vaccines post-booster immune responses to 10 common serotypes appeared similar to those elicited by PHiD-CV. Safety and reactogenicity profiles of the investigational vaccines were comparable to PHiD-CV. Clinical trial registry: NCT01204658.

Anamnestic Immune Response and Safety of an Inactivated Quadrivalent Influenza Vaccine in Primed Versus Vaccine-Naïve Children.

BACKGROUND: It has not yet been demonstrated whether 2 doses of inactivated quadrivalent influenza vaccine (IIV4) prime a booster response in infants. We evaluated the anamnestic immune response to an IIV4 in children 17-48 months of age. METHODS: Children were randomized to 2 doses of IIV4 or control in the primary phase III study (NCT01439360). One year later, in an open-label revaccination extension study (NCT01702454), a subset of children who received IIV4 in the primary study (primed group) received 1 IIV4 dose and children who received control in the primary study (unprimed) received 2 IIV4 doses 28 days apart. The primary objective was to evaluate hemagglutination inhibition (HI) antibody titers 7 days after first IIV4 vaccination in the per-protocol cohort (N = 224 primed; N = 209 unprimed). Neutralizing and antineuraminidase antibodies were also measured. Safety was analyzed in the total vaccinated cohort (N = 241 primed; N = 229 unprimed). RESULTS: An anamnestic response was observed in primed children relative to unprimed controls, measured by age-adjusted geometric mean HI titer ratios against strains homologous (A/H1N1: 9.0; B/Victoria: 3.9) and heterologous (A/H3N2: 2.7; B/Yamagata: 6.7) to those in the primary vaccination series. The anamnestic response in primed children included increases in neutralizing antibodies (mean geometric increase: 5.0-10.6) and antineuraminidase antibodies (4.9-8.8). No serious adverse events related to vaccination were reported. CONCLUSIONS: In this study, 2-dose priming with IIV4 induced immune memory that was recalled with 1-dose IIV4 the following year to boost HI, antineuraminidase and neutralizing antibodies, even though the IIV4 strain composition partially changed.

Immunogenicity and Reactogenicity of DTPa-HBV-IPV/Hib and PHiD-CV When Coadministered With MenACWY-TT in Infants: Results of an Open, Randomized Trial.

BACKGROUND: This study evaluated the immunogenicity and reactogenicity of a combined diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliovirus virus-Haemophilus influenzae type b vaccine (DTPa-HBV-IPV/Hib) and a 10-valent pneumococcal conjugate vaccine (PHiD-CV) coadministered with a quadrivalent meningococcal conjugate vaccine (MenACWY-TT) in infants/toddlers. METHODS: In this open, controlled, phase III study (NCT01144663), 2095 healthy infants were randomized (1:1:1:1) into 4 groups to receive MenACWY-TT at 2, 3, 4 and 12 months of age or MenACWY-TT, MenC-CRM197, or MenC-TT at 2, 4 and 12 months of age. All participants received PHiD-CV and DTPa-HBV-IPV/Hib at 2, 3, 4 and 12 months of age. Immunogenicity of DTPa-HBV-IPV/Hib was evaluated in exclusive randomized subsets of 25% of participants from each group postprimary, prebooster and postbooster vaccination, whereas immunogenicity of PHiD-CV was evaluated at all time points. Reactogenicity was evaluated on the total vaccinated cohorts during 8 days after each vaccination. RESULTS: For each DTPa-HBV-IPV/Hib antigen, ≥97.2%, ≥76.5% and ≥97.9% of participants had seropositive/seroprotective levels 1 month postprimary vaccination, before the booster dose and 1 month postbooster, respectively. For each vaccine pneumococcal serotype, ≥74.0% of infants had antibody concentrations ≥0.35 µg/mL at 1 month postprimary vaccination, and robust increases in antibody geometric mean concentrations were observed from prebooster to postbooster. Redness was the most frequent solicited local symptom at the DTPa-HBV-IPV/Hib and PHiD-CV injection sites, reported after up to 47.7% and 57.0% of doses postprimary and postbooster vaccination, respectively. CONCLUSIONS: Primary and booster vaccinations of infants/toddlers with DTPa-HBV-IPV/Hib and PHiD-CV coadministered with MenACWY-TT were immunogenic with clinically acceptable reactogenicity profiles. These results support the coadministration of MenACWY-TT with routine childhood vaccines.

Antibody persistence and booster responses 24-36 months after different 4CMenB vaccination schedules in infants and children: A randomised trial.

OBJECTIVES: This phase IIIb, open-label, multicentre, extension study (NCT01894919) evaluated long-term antibody persistence and booster responses in participants who received a reduced 2 + 1 or licensed 3 + 1 meningococcal serogroup B vaccine (4CMenB)-schedule (infants), or 2-dose catch-up schedule (2-10-year-olds) in parent study NCT01339923. MATERIALS AND METHODS: Children aged 35 months to 12 years (N = 851) were enrolled. Follow-on participants (N = 646) were randomised 2:1 to vaccination and non-vaccination subsets; vaccination subsets received an additional 4CMenB dose. Newly enrolled vaccine-naïve participants (N = 205) received 2 catch-up doses, 1 month apart (accelerated schedule). Antibody levels were determined using human serum bactericidal assay (hSBA) against MenB indicator strains for fHbp, NadA, PorA and NHBA. Safety was also evaluated. RESULTS: Antibody levels declined across follow-on groups at 24-36 months versus 1 month post-vaccination. Antibody persistence and booster responses were similar between infants receiving the reduced or licensed 4CMenB-schedule. An additional dose in follow-on participants induced higher hSBA titres than a first dose in vaccine-naïve children. Two catch-up doses in vaccine-naïve participants induced robust antibody responses. No safety concerns were identified. CONCLUSION: Antibody persistence, booster responses, and safety profiles were similar with either 2 + 1 or 3 + 1 vaccination schedules. The accelerated schedule in vaccine-naïve children induced robust antibody responses.

Safety and Immunogenicity of the Quadrivalent Meningococcal Serogroups A, C, W and Y Tetanus Toxoid Conjugate Vaccine Coadministered With Routine Childhood Vaccines in European Infants: An Open, Randomized Trial.

BACKGROUND: This was the first study evaluating the immunogenicity and safety of the quadrivalent meningococcal tetanus toxoid conjugate vaccine (MenACWY-TT) coadministered with routine childhood vaccines in young infants. METHODS: In this open, randomized, controlled, phase III study (NCT01144663), 2095 infants (ages 6-12 weeks) were randomized (1:1:1:1) into 4 groups to receive MenACWY-TT at 2, 3, 4 and 12 months of age, or MenACWY-TT, MenC-cross-reactive material (CRM197) or MenC-TT at 2, 4 and 12 months of age. All participants received PHiD-CV and DTPa-HBV-IPV/Hib at 2, 3, 4 and 12 months of age. Immune responses were measured by serum bactericidal activity assays using rabbit (rSBA) and human (hSBA) complement. Solicited and unsolicited symptoms were recorded during 8 and 31 days post-vaccination, respectively, and serious adverse events throughout the study. RESULTS: Noninferiority of immune responses to MenC induced by 2 or 3 doses of MenACWY-TT versus 2 doses of MenC-TT or MenC-CRM197 was demonstrated. Predefined criteria for the immunogenicity of MenACWY-TT to MenA, MenW and MenY were met. One month after 2 or 3 primary MenACWY-TT doses, ≥93.1% and ≥88.5% of infants had rSBA and hSBA titers ≥1:8 for all serogroups. The robust increases in rSBA and hSBA titers observed for all vaccine serogroups postbooster vaccination suggested that MenACWY-TT induced immune memory. MenACWY-TT coadministered with childhood vaccines had a clinically acceptable safety profile. CONCLUSIONS: This study supports the coadministration of MenACWY-TT with routine childhood vaccines as 2 or 3 primary doses during infancy followed by a booster dose in the second year of life.

A phase 1, open-label safety and immunogenicity study of an AS03-adjuvanted trivalent inactivated influenza vaccine in children aged 6 to 35 months.

BACKGROUND:  There is a need for better vaccines and vaccine strategies to reduce the burden of influenza in very young children.   METHODS:  This phase 1, open-label study assessed the reactogenicity, safety, and immunogenicity of an inactivated trivalent influenza vaccine (TIV) containing low doses of hemagglutinin antigen (7.5 µg each strain), adjuvanted with a tocopherol-based oil-in-water emulsion Adjuvant System (AS03). Influenza vaccine-naïve children aged 6-35 months were sequentially enrolled to receive TIV-AS03D (1.48 mg tocopherol) or TIV-AS03C (2.97 mg tocopherol), then a 6-month booster of conventional TIV. The primary endpoint was the incidence of fever (axillary temperature >38 °C) for 7 days post-vaccination. Immune responses were assessed by hemagglutination-inhibition (HI) assay. RESULTS:  Forty children were sequentially enrolled into the TIV-AS03D or the TIV-AS03C group. Fever >38.0 °C was reported in 5/20 (25.0%) and 7/20 (35.0%) children after the first and second doses of TIV-AS03D, respectively, and in 7/20 (35.0%) children after 1 dose of TIV-AS03C; the latter fulfilled the holding rule for safety, and the second dose of TIV-AS03C was cancelled. HI immune responses exceeded adult European licensure criteria for the immunogenicity, and all children had HI antibody titers ≥ 1:40 after 1 dose of TIV booster against booster strains. CONCLUSIONS:  One dose of primary vaccine containing a low dose of antigen and AS03 may be a possible influenza vaccination strategy for young children. The relatively high frequency of fever warrants further investigation, although the generalizability of the findings are uncertain given that many of the children had antibody evidence suggesting recent infection with A(H1N1)pdm09.

Immunogenicity and safety of an inactivated quadrivalent influenza vaccine candidate: a phase III randomized controlled trial in children.

BACKGROUND: Mismatch between circulating influenza B viruses (Yamagata and Victoria lineages) and vaccine strains occurs frequently. METHODS: In a randomized controlled trial, immunogenicity and safety of an inactivated quadrivalent influenza vaccine candidate (QIV) versus trivalent inactivated influenza vaccine (TIV)-Victoria(Vic) and TIV-Yamagata(Yam) in children 3-17 years of age was evaluated. In an open-label study arm, QIV only was assessed in children 6-35 months of age. RESULTS: A total of 3094 children (932 QIV, 929 TIV-Vic, 932 TIV-Yam, and 301 QIV only) were vaccinated. QIV was noninferior to the TIVs for shared strains (A/H3N2 and A/H1N1) based on hemagglutination-inhibition (HI) antibodies 28 days after last vaccination, and superior for the unique B strains Victoria and Yamagata (geometric mean titer ratios 2.61, 3.78; seroconversion rate differences 33.96%, 44.63%). Among children in the randomized trial, adverse event rates were similar except for injection site pain (dose 1: 65.4% QIV, 54.6% TIV-Vic, 55.7% TIV-Yam). CONCLUSION: QIV elicited superior HI responses to the added B strains compared to TIV controls, potentially improving its effectiveness against influenza B. HI responses were similar between QIV and TIV controls for the shared strains. QIV had an acceptable safety profile relative to TIVs. CLINICAL TRIALS REGISTRATION: NCT01198756.