Safety and immunogenicity of the NVX-CoV2373 vaccine as a booster in adults previously vaccinated with the BBIBP-CorV vaccine.

This phase 3 observer-blind, randomized, controlled study was conducted in adults ≥18 years of age to assess the safety and immunogenicity of NVX-CoV2373 as a heterologous booster compared to BBIBP-CorV when utilized as a homologous booster. Approximately 1000 participants were randomly assigned in a 1:1 ratio to receive a single dose of NVX-CoV2373 or BBIBP-CorV after prior vaccination with 2 or 3 doses of BBIBP-CorV. Solicited adverse events (AEs) were collected for 7 days after vaccination. Unsolicited AEs were collected for 28 days following the booster dose and serious adverse and adverse events of special interest (AESI) were collected throughout the study. Anti-spike IgG and neutralizing antibodies against SARS-CoV-2 were measured at baseline, day 14, day 28, and day 180. The study achieved its primary non-inferiority endpoint and also demonstrated statistically higher neutralization responses when NVX-CoV2373 was utilized as a heterologous booster compared with BBIBP-CorV as a homologous booster. Both vaccines had an acceptably low reactogenicity profile, and no new safety concerns were found. Heterologous boosting with NVX-CoV2373 was a highly immunogenic and safe vaccine regimen in those previously vaccinated with BBIBP-CorV.

Going Forward: Potential Impact of Protein-Based COVID-19 Vaccination Coverage on Population Outcomes and Costs in the United States.

Policymakers in the United States (US) recommend coronavirus disease 2019 (COVID-19) vaccination with a monovalent 2023-2024 vaccine formulation based on the Omicron XBB.1.5 variant. We estimated the potential US population-level health and economic impacts of increased COVID-19 vaccine coverage that might be expected with the availability of a protein-based vaccine with simpler storage requirements in addition to messenger ribonucleic acid (mRNA) vaccines. A Markov model was developed to estimate 1-year COVID-19-related costs, cases, hospitalizations, and deaths with and without the availability of a protein-based vaccine option. The model population was stratified by age and risk status. Model inputs were sourced from published literature or derived from publicly available data. Our model estimated that a five-percentage-point increase in coverage due to the availability of a protein-based vaccine option would prevent over 500,000 cases, 66,000 hospitalizations, and 3000 COVID-19-related deaths. These clinical outcomes translated to 42,000 quality-adjusted life years (QALYs) gained and an incremental cost-effectiveness ratio of USD 16,141/QALY from a third-party payer perspective. In sensitivity analyses, outcomes were most sensitive to COVID-19 incidence and severity across age groups. The availability of a protein-based vaccine option in the US could reduce hospitalizations and deaths and is predicted to be cost-effective.

Burden and Impact of Reactogenicity among Adults Receiving COVID-19 Vaccines in the United States and Canada: Results from a Prospective Observational Study.

As SARS-CoV-2 variants continue to emerge, vaccination remains a critical tool to reduce the COVID-19 burden. Vaccine reactogenicity and the impact on work productivity/daily activities are recognized as contributing factors to vaccine hesitancy. To encourage continued COVID-19 vaccination, a more complete understanding of the differences in reactogenicity and impairment due to vaccine-related side effects across currently available vaccines is necessary. The 2019nCoV-406 study (n = 1367) was a prospective observational study of reactogenicity and associated impairments in adults in the United States and Canada who received an approved/authorized COVID-19 vaccine. Compared with recipients of mRNA COVID-19 booster vaccines, a smaller percentage of NVX-CoV2373 booster recipients reported local and systemic reactogenicity. This study's primary endpoint (percentage of participants with ≥50% overall work impairment on ≥1 of the 6 days post-vaccination period) did not show significant differences. However, the data suggest that NVX-CoV2373 booster recipients trended toward being less impaired overall than recipients of an mRNA booster; further research is needed to confirm this observed trend. The results of this real-world study suggest that NVX-CoV2373 may be a beneficial vaccine option with limited impact on non-work activities, in part due to the few reactogenicity events after vaccination.

The Novavax Heterologous COVID Booster Demonstrates Lower Reactogenicity Than mRNA: A Targeted Review.

COVID-19 continues to be a global health concern and booster doses are necessary for maintaining vaccine-mediated protection, limiting the spread of SARS-CoV-2. Despite multiple COVID vaccine options, global booster uptake remains low. Reactogenicity, the occurrence of adverse local/systemic side effects, plays a crucial role in vaccine uptake and acceptance, particularly for booster doses. We conducted a targeted review of the reactogenicity of authorized/approved mRNA and protein-based vaccines demonstrated by clinical trials and real-world evidence. It was found that mRNA-based boosters show a higher incidence and an increased severity of reactogenicity compared with the Novavax protein-based COVID vaccine, NVX-CoV2373. In a recent NIAID study, the incidence of pain/tenderness, swelling, erythema, fatigue/malaise, headache, muscle pain, or fever was higher in individuals boosted with BNT162b2 (0.4 to 41.6% absolute increase) or mRNA-1273 (5.5 to 55.0% absolute increase) compared with NVX-CoV2373. Evidence suggests that NVX-CoV2373, when utilized as a heterologous booster, demonstrates less reactogenicity compared with mRNA vaccines, which, if communicated to hesitant individuals, may strengthen booster uptake rates worldwide.

Safety of the NVX-CoV2373 COVID-19 vaccine in randomized placebo-controlled clinical trials.

BACKGROUND: NVX-CoV2373 (Nuvaxovid™ or the Novavax COVID-19 Vaccine, Adjuvanted), the first protein-based COVID-19 vaccine, received emergency use authorization (EUA) as a primary series/booster and is available globally. NVX-CoV2373 primary series demonstrated efficacy rates of 89.7-90.4 % and an acceptable safety profile. This article summarizes safety in adult recipients (aged ≥ 18 years) of primary series NVX-CoV2373 in four randomized placebo-controlled trials. METHODS: All participants who received NVX-CoV2373 primary series or placebo (pre-crossover) were included according to actual received treatment. The safety period was from Day 0 (first vaccination) to unblinding/receipt of EUA-approved/crossover vaccine, end of each study (EOS), or last visit date/cutoff date minus 14 days. The analysis reviewed local and systemic solicited adverse events (AEs) within 7 days after NVX-CoV2373 or placebo; unsolicited AEs from after Dose 1 to 28 days after Dose 2; serious AEs (SAEs), deaths, AEs of special interest, and vaccine-related medically attended AEs from Day 0 through end of follow-up (incidence rate per 100 person-years). FINDINGS: Pooled data from 49,950 participants (NVX-CoV2373, n = 30,058; placebo, n = 19,892) were included. Solicited reactions after any dose were more frequent in NVX-CoV2373 recipients (local, 76 %/systemic, 70 %) than placebo recipients (local, 29 %/systemic, 47 %), and were mostly of mild-to-moderate severity. Grade 3+ reactions were infrequent, with greater frequency in NVX-CoV2373 recipients (local, 6.28 %/systemic, 11.36 %) than placebo recipients (local, 0.48 %/systemic, 3.58 %). SAEs and deaths occurred with similarly low frequency in NVX-CoV2373 (SAEs: 0.91 %, deaths: 0.07 %) and placebo recipients (SAEs: 1.0 %, deaths: 0.06 %). INTERPRETATION: To date, NVX-CoV2373 has displayed an acceptable safety profile in healthy adults. FUNDING: Supported by Novavax, Inc.

Impact of adherence to treatment with inhaled corticosteroids/long-acting ß-agonists on asthma outcomes in the United States.

BACKGROUND: Suboptimal adherence to maintenance medication has been associated with poor outcomes in asthma. This study examined single-inhaler inhaled corticosteroid (ICS)/long-acting ß2 agonist (LABA) adherence and asthma-related outcomes. METHODS: This retrospective observational study of patients with asthma initiating ICS/LABA used data from IQVIA PharMetrics Plus (1 January 2014-31 March 2019). Patients included were ⩾18 years old and had ⩾12 months continuous eligibility before, and ⩾180 days follow-up after, the index date. Adherence was measured as proportion of days covered ([PDC] adherent ⩾ 0.8; non-adherent <0.8) each quarter, with outcomes measured each subsequent quarter. Endpoints were asthma-related overall and severe (inpatient/emergency department [ED] visit) exacerbations, rescue medication use, and asthma-related healthcare resource utilization and costs. Regression models evaluated associations between adherence and outcomes, controlling for repeated measures and differences in baseline characteristics. RESULTS: Overall, 50,037 patients were included (mean age 45.3 years; mean follow-up 23.3 months). Adherent patients were less likely to experience asthma-related overall (adjusted odds ratio [aOR] 95% confidence interval [CI]: 0.942 [0.890, 0.998]; p = 0.041), or severe exacerbations (aOR [95% CI]: 0.778 [0.691, 0.877]; p < 0.001) per quarter versus non-adherent patients. Adherent patients had lower severe exacerbation rates (adjusted rate ratio [aRR] [95% CI]: 0.792 [0.702, 0.893]; p < 0.001) but similar overall exacerbation rates (aRR [95% CI]: 0.993 [0.945, 1.044]; p = 0.783) versus non-adherent patients. The odds of rescue medication use were lower per 20% PDC increase (aOR [95% CI] short-acting ß2 agonist: 0.991 [0.985, 0.996]; p = 0.001; oral corticosteroid: 0.988 [0.982, 0.995]; p < 0.001). Adherent patients were less likely to visit EDs per quarter (aOR [95% CI]: 0.775 [0.680, 0.883]; p < 0.001) and odds of hospitalization were lower per 20% PDC increase (aOR [95% CI]: 0.930 [0.881, 0.982]; p = 0.009). Across most measures, adherent patients incurred lower costs. CONCLUSION: This real-world study highlights the short-term clinical and economic benefits of ICS/LABA adherence in asthma, particularly in reducing severe exacerbations.

Growth in health care data causing an evolution in the pharmaceutical industry.

A health care ecosystem is evolving in which all stakeholders will need to work together, apply new technologies, and use disparate data sources to gain insights, increase efficiencies, and improve patient outcomes. The pharmaceutical industry is leveraging its experience and analytics capabilities to play an important role in this evolution.

Immunogenicity of a quadrivalent Ann Arbor strain live attenuated influenza vaccine delivered using a blow-fill-seal device in adults: a randomized, active-controlled study*.

BACKGROUND: Influenza B strains from two distinct lineages (Yamagata and Victoria) have cocirculated over recent years. Current seasonal vaccines contain a single B lineage resulting in frequent mismatches between the vaccine strain and the circulating strain. An Ann Arbor strain quadrivalent live attenuated influenza vaccine (Q/LAIV) containing B strains from both lineages is being developed to address this issue. OBJECTIVES: The goal of this study was to evaluate whether Q/LAIV administered intranasally as a single dose to a single nostril, using a blow-fill-seal (BFS) delivery system had a similar immunogenicity and safety profile compared with the licensed trivalent vaccine delivered using the Accuspray device. PATIENTS/METHODS: Adults aged 18-49 years were randomized to receive one intranasal dose of Q/LAIV delivered using a BFS device (Q/LAIV-BFS; n=1202) or one of two trivalent live attenuated influenza vaccines (T/LAIV) containing one of the corresponding B strains (total T/LAIV, n=598). Primary endpoints were the post-vaccination strain-specific serum hemagglutination inhibition antibody geometric mean titers for each strain. Secondary immunogenicity endpoints, safety, and acceptability of the BFS device were also assessed. RESULTS: Q/LAIV was immunogenically non-inferior to T/LAIV for all four influenza strains. Secondary immunogenicity outcomes were consistent with the primary endpoint. Solicited symptoms and AEs were comparable in both groups. Subjects considered the BFS device to be acceptable. CONCLUSIONS: Immune responses to vaccination with Ann Arbor strain Q/LAIV-BFS were non-inferior to those with T/LAIV. Q/LAIV may confer broader protection against seasonal influenza B by targeting both major influenza B lineages.

The comparative value of various employer-sponsored influenza vaccination clinics.

OBJECTIVE: Many US firms offer influenza vaccination clinics to prevent lost productivity due to influenza. Strategies to promote and offer vaccination differ, and the economic value of the strategies is unknown. METHODS: Decision analytic modeling and Monte Carlo probabilistic sensitivity analyses estimated the one-season cost-consequences of three types of influenza clinics (trivalent inactivated influenza vaccine only, vaccine choice [trivalent inactivated influenza or intranasal {live attenuated influenza} vaccine], or vaccine choice plus incentive) in firms of 50 and 250 employees, from the employer's perspective. RESULTS: On-site influenza vaccination was generally cost-saving over no vaccination. For the scenario of vaccine effectiveness of 70% and intermediate transmissibility, the incremental costs per employee for a firm of 50 employees were -$6.41 (ie, cost savings) for inactivated vaccine only versus no vaccination, -$1.48 for vaccine choice versus inactivated vaccine, and $1.84 for vaccine choice plus incentive versus vaccine choice. Clinics offering a choice of vaccines were slightly less costly under many scenarios. Generally, incremental costs were lower (1) in larger firms; (2) when influenza was assumed to be more contagious; and (3) when vaccine effectiveness was assumed to be higher. CONCLUSION: Employer-sponsored influenza vaccination clinics are generally cost-saving.

Agreement between Internet-based self- and proxy-reported health care resource utilization and administrative health care claims.

OBJECTIVES: Although Internet-based surveys are becoming more common, little is known about agreement between administrative claims data and Internet-based survey self- and proxy-reported health care resource utilization (HCRU) data. This analysis evaluated the level of agreement between self- and proxy-reported HCRU data, as recorded through an Internet-based survey, and administrative claims-based HCRU data. METHODS: The Child and Household Influenza-Illness and Employee Function study collected self- and proxy-reported HCRU data monthly between November 2007 and May 2008. Data included the occurrence and number of visits to hospitals, emergency departments, urgent care centers, and outpatient offices for a respondent's and his or her household members' care. Administrative claims data from the MarketScan® Databases were assessed during the same time and evaluated relative to survey-based metrics. Only data for individuals with employer-sponsored health care coverage linkable to claims were included. The Kappa (κ) statistic was used to evaluate visit concordance, and the intraclass correlation coefficient was used to describe frequency consistency. RESULTS: Agreement for presence of a health care visit and the number of visits were similar for self- and proxy-reported HCRU data. There was moderate to substantial agreement related to health care visit occurrence between survey-based and claims-based HCRU data for inpatient, emergency department, and office visits (κ: 0.47-0.77). There was less agreement on health care visit frequencies, with intraclass correlation coefficient values ranging from 0.14 to 0.71. CONCLUSIONS: This study's agreement values suggest that Internet-based surveys are an effective method to collect self- and proxy-reported HCRU data. These results should increase confidence in the use of the Internet for evaluating disease burden.

Elementary school-located influenza vaccine programs: key stakeholder experiences from initiation to continuation.

This study examined the initiation and logistics, funding, perceived barriers and benefits, and disruption of school activities by school-located influenza vaccination (SLIV) programs conducted during the 2008-2009 influenza season. Seventy-two interviews using a structured protocol were conducted with 26 teachers, 16 school administrators, and 30 health care professionals from 34 schools in 8 school districts. SLIV programs used a variety of locations, scheduling and staffing options, and methods for receiving parental consent and screening children. Health care professionals were primarily responsible for implementing SLIV programs, and most administrators and health care professionals considered programs easy to initiate. Health care professionals identified successful programs as requiring adequate planning/coordination, a dedicated program coordinator, and a consistent funding source. Most respondents (96%) reported minimal school-day disruptions. The perception of most stakeholders is that SLIV programs can be relatively easy to initiate, minimally disruptive and can become more efficient with experience, especially with feedback from all stakeholders.

A survey of children's preferences for influenza vaccine attributes.

BACKGROUND: While annual influenza vaccination is recommended by the CDC for children 6 months and older, vaccination rates remain suboptimal. For healthy, US children 2 years of age and older, influenza vaccine is available as an intramuscular injection (TIV) or an intranasal spray (LAIV), respectively. Little is known about children's experiences and preferences for influenza vaccine attributes. OBJECTIVE: To examine preferences for influenza vaccine attributes and their relative importance among children. METHODS: A quantitative web-survey was administered to children aged 8-12 years sampled from a standing online panel representative of the US population. Children were stratified by age, gender and parent's influenza vaccination behavior. The survey included questions to ascertain children's preferences for influenza vaccine attributes, including efficacy, chance of common side effects, and mode of administration. It included conjoint (trade-off) questions in which children traded-off different attributes in their choice between two influenza vaccines with differing features. We also surveyed children's comprehension of and ability to complete the conjoint questions. RESULTS: 544 children completed the survey (response rate 37%). Children most frequently selected efficacy as the most important vaccine attribute followed by mode of administration (45% and 31%, respectively). When asked for their preference to receive influenza vaccine as a "shot" or a "nose spray", the majority (69%) preferred the nose spray. An evaluation of children's ability to complete the conjoint survey demonstrated that 85% of the sample was able to complete the conjoint tasks. Analysis of the conjoint responses demonstrated that mode of administration and efficacy had the greatest impact on preferences, with a relative importance of 40.5% and 30.6%, respectively. In a direct comparison of vaccine profiles representing the efficacy, side effects, and other characteristics of LAIV and TIV, 79% of children preferred the LAIV-like profile. CONCLUSION: Children in the sample had consistent opinions regarding influenza vaccine attributes and consider vaccine efficacy and mode of administration to be important. Children can be informed participants in influenza prevention and can be included in discussions regarding influenza vaccination.

Children's perceptions of influenza illness and preferences for influenza vaccine.

INTRODUCTION: In this qualitative study we explored children's perceptions of influenza, preferences for influenza vaccines, and ability to understand "risk" of vaccine adverse effects and different attributes between injectable and intranasal vaccines. METHOD: In-person, semi-structured interviews were conducted among 28 U.S. children aged 6 through 12 years. RESULTS: Many children understood the concept of influenza illness and believed vaccination was important. Efficacy, adverse effects, and mode of administration affected their preferences for influenza vaccines. Children 8 years of age and older were able to consider multiple attributes when selecting between hypothetical vaccines, and their responses were consistent with their previously stated preferences for individual attributes. Most children would prefer a nasal spray over a shot vaccine when all other vaccine attributes were equal. DISCUSSION: Efficacy, adverse effects, and mode of administration were important factors in children's preferences for influenza vaccine. Children as young as 8 years of age appeared to understand vaccine "risk" and were able to consider multiple attributes simultaneously when choosing between vaccine alternatives.

Parent preferences for pediatric influenza vaccine attributes.

Influenza vaccine is available as an intramuscular injection or an intranasal spray for eligible children. This study was conducted to examine parents' preferences for influenza vaccine attributes and the attributes' relative importance regarding the vaccination of their children. A quantitative Web survey was administered to 500 parents of children aged 2 to 12 years. The survey included general preference questions and conjoint (trade-off) questions. Parents most frequently selected efficacy, risk of temporary side effects, and physician recommendation as important vaccine attributes from a provided list (92%, 75%, and 59%, respectively). For attributes selected as important, parents rated the importance of the attribute; the highest mean importance ratings were given to efficacy, presence of mercury-containing preservative, and physician recommendation.The highest relative importance ratings in the conjoint section were given to efficacy and presence of mercury-containing preservative. Parental education on influenza vaccine efficacy and safety may help to improve pediatric vaccination rates.

Attending work while sick: implication of flexible sick leave policies.

OBJECTIVE: To examine the impact of various flexible sick leave policies (FSLPs) on workplace attendance of employees with self-reported "severe" influenza-like-illness (ILI) symptoms. METHODS: This is a prospective study of employees from three US employers, which involved collection of information on employees' access to FSLPs and monthly experience with ILI and workplace attendance from November 2007 to April 2008. Multivariate analyses were used to estimate the impact of FSLPs on employees' workplace attendance while they were experiencing severe ILI symptoms. RESULTS: Among 793 employees with ILI, the average duration of severe ILI symptoms was 3.0 days. Most employees (71.9%) attended work with severe ILI symptoms, for an average of 1.3 days. Employees who could telework had a 29.7% lower rate of attending work with severe ILI symptoms (P = 0.026). CONCLUSIONS: Employers that implement teleworking policies may be able to reduce employee-to-employee transmission of respiratory illness, including seasonal and pandemic influenza.

Employees' willingness to pay to prevent influenza.

OBJECTIVES: To quantify employees' preferences, as measured by willingness to pay, to prevent influenza in themselves and in their child and adult household members and to examine factors associated with willingness to pay. STUDY DESIGN: Prospective observational cohort study of a convenience sample of employees from 3 large US employers. Participants had at least 1 child (< or = 17 years) living in their household for at least 4 days per week. METHODS: Each month from November 2007 to April 2008, employees completed Web-based surveys regarding acute respiratory illness in their household. In the final survey, employees were presented with descriptions of influenza and questions regarding their willingness to pay to prevent influenza. Factors associated with willingness to pay were examined using multivariate ordinary least squares regression analysis of the log of willingness to pay. RESULTS: Among 2006 employees, 31.3% were female, the mean age was 41.7 years, 85.3% were of white race/ethnicity, and the mean household size was 4.0. Employees' median (mean) willingness to pay to prevent influenza was $25 ($72) for themselves, $25 ($82) for their adult household members, and $50 ($142) (P <.01) for children. However, influenza vaccination rates were approximately equal for children (27.5%), employees (31.5%), and other adult household members (24.5%). This finding may be explained by barriers such as cost, dislike of vaccinations, and disagreement with national influenza vaccination recommendations, which were significantly associated with lower willingness to pay for prevention of influenza (P <.05). CONCLUSION: Employees expressed a stronger preference to prevent influenza in their children than in themselves or other household members; however, modifiable barriers depress vaccination rates.

Parents' decision-making regarding vaccinating their children against influenza: A web-based survey.

BACKGROUND: Despite the recommendation from the Centers for Disease Control and Prevention that children between the ages of 6 months and 18 years be vaccinated against influenza annually, vaccination rates remain suboptimal. OBJECTIVES: This study was conducted to explore factors that influence parents' decisions regarding influenza vaccination for children aged 2 to 12 years, to quantify the relative importance of these factors, to identify an appropriate theoretical model for illustrating the relationships among these factors, and to characterize parents by their likelihood of vaccinating their children against influenza. METHODS: A quantitative Web-based survey was administered to a sample of parents from an online panel representative of the US population. Parents were stratified based on self-reported rates of their personal influenza vaccination (every year, sometimes, or never) and the age of their child (2-4 years or 5-12 years). The results were examined by parents' likelihood of vaccinating their child in the next year (high, medium, or low). Participants were asked to rank their agreement with statements representing various beliefs and perceptions about influenza and influenza vaccine on a scale from 1 = strongly agree to 5 = strongly disagree. Parents who indicated that they vaccinate their child every year were asked to select the drivers of their decision to vaccinate; parents who indicated that they never vaccinate their child were asked to select the barriers affecting their decision not to vaccinate; and parents who responded that they sometimes vaccinate their child were asked to select both the drivers and barriers affecting their decision. Participants were then asked to rank the importance of each driver or barrier on a scale from 1 = a little important to 5 = extremely important. Mean agreement ratings were calculated for parents' beliefs and perceptions about influenza and influenza vaccine and were compared across likelihood subgroups. Mean importance ratings of the drivers and barriers to vaccination were also calculated and compared across likelihood subgroups. RESULTS: The survey sample consisted of 500 parents; their mean (SD) age was 37.4 (6.82) years, 57.2% were female, and 78.2% were non-Hispanic white. Among those who reported that they vaccinated their child against influenza every year or sometimes, the major drivers of vaccination were prevention of influenza (95.1%), a doctor's recommendation (89.5%), and the desire to reduce influenza symptoms (83.3%). Among those who reported sometimes or never vaccinating their child against influenza, barriers to vaccination were more variable. The most common barriers were low perceived risk of influenza (46.0%), the perception that the vaccine caused influenza (44.0%), and side effects caused by the vaccine (36.6%). Distinct differences were found in beliefs and perceptions of influenza and influenza vaccine according to respondents' likelihood of vaccination. A high likelihood of vaccination was associated with a greater perceived threat of influenza and less concern about the efficacy and safety of the vaccine. Convenience was an important factor among parents with a medium likelihood of vaccination. The Health Belief Model was identified as an appropriate theoretical framework for illustrating the factors influencing parents' decision-making about influenza vaccination. CONCLUSIONS: Prevention of influenza, reduction of influenza symptoms, and doctor recommendation were the main drivers of parents' decision to vaccinate their child against influenza. Barriers to vaccination were more variable and primarily included the risk of adverse effects and the perceived low risk of influenza. Increasing parents' awareness of the threat of influenza and the efficacy and safety of the vaccine, as well as improving the convenience of getting vaccinated, may help improve rates of pediatric influenza vaccination.

Importance of vaccination habit and vaccine choice on influenza vaccination among healthy working adults.

This randomized cluster trial was designed to improve workplace influenza vaccination rates using enhanced advertising, choice of vaccine type (intranasal or injectable) and an incentive. Workers aged 18-49 years were surveyed immediately following vaccination to determine factors associated with vaccination behavior and choice. The questionnaire assessed attitudes, beliefs and social support for influenza vaccine, demographics, and historical, current, and intentional vaccination behavior. Of the 2389 vaccinees, 83.3% received injectable vaccine and 16.7% received intranasal vaccine. Factors associated with previous influenza vaccination were older age, female sex, higher education and greater support for injectable vaccine (all P<.02). Current influenza vaccination with intranasal vaccine vs. injectable vaccine was associated with higher education, the study interventions, greater support for the intranasal vaccine and nasal sprays, less support of injectable vaccine, more negative attitudes about influenza vaccine, and a greater likelihood of reporting that the individual would not have been vaccinated had only injectable vaccine been offered (all P<.01). Intentional vaccine choice was most highly associated with previous vaccination behavior (P<.001). A key to long term improvements in workplace vaccination is to encourage first time influenza vaccination through interventions that include incentives, publicity and vaccine choice.