Doses Of Influenza Vaccine Research Articles

GELATIN-INDUCED VACCINE ANAPHYLAXIS MISATTRIBUTED TO EGG ALLERGY

Introduction Vaccine-related anaphylaxis is rare, occurring at a rate of 1 per million vaccine doses. All suspected anaphylactic reactions should be evaluated with allergy testing to both the vaccine and its components. We report on a case of anaphylaxis following both 12- and 15-month immunizations. Case Description A 17-month old male was referred for evaluation of anaphylaxis to vaccines. At 12 months of age he received initial doses of Influenza, MMR, Hepatitis A, and Pneumococcal 13-valent vaccines. Fifteen minutes following administration he developed coughing, pruritus, and facial/lip angioedema. He was evaluated in an ED and received intramuscular epinephrine for presumed influenza vaccine anaphylaxis secondary to egg hypersensitivity. Three months later he developed cough and facial/lip angioedema within five minutes of his 15-month immunizations (Varicella, DTaP, and Haemophilus B vaccines). Skin testing was positive for Gelatin (11 mm), Egg (9 mm), MMR (5 mm), and Varicella (9 mm), and negative to Influenza (3 mm) with appropriate histamine and saline controls. RAST testing was positive to Bovine Gelatin (25.1 kU/L) and negative to Egg ( Discussion A previous study of MMR vaccine anaphylaxis found 27% of affected patients had anti-gelatin IgE, while none reported gelatin food allergy. MMR, Varicella, Zoster, and Rabies vaccines contain >10,000μg of gelatin/dose with much smaller amounts in influenza vaccines. We concluded that our patient was sensitized to gelatin, and reacted to gelatin-containing vaccines. Proper allergy evaluation is essential following vaccine-related reactions, as unnecessary avoidance can be associated with serious health consequences.

High-Dose Seasonal Influenza Vaccine in Patients Undergoing Dialysis.

High-dose influenza vaccine, which contains fourfold more antigen than standard dose, is associated with fewer cases of influenza and less influenza-related morbidity in the elderly general population. Whether the high-dose influenza vaccine benefits patients on dialysis, whose immune response to vaccination is less robust than that of healthy patients, is uncertain. We compared hospitalizations and deaths during the 2015-2016 and 2016-2017 influenza seasons by vaccine type (standard trivalent, standard quadrivalent, and high-dose trivalent influenza vaccine) administered within a national dialysis organization. The association of vaccine type with outcomes was estimated using Cox proportional hazards regression with adjustment for patient factors and "center effect." Analyses were stratified by age and dialysis modality. Between September 1 and December 31, 2015, standard dose trivalent, standard dose quadrivalent, and high-dose trivalent influenza vaccines were administered to 3057 (31%), 5981 (61%), and 805 (8%) patients, respectively. The adjusted rates of first hospitalizations by vaccine type during the influenza season were 8.43, 7.88, and 7.99 per 100 patient-months, respectively, and the adjusted rates of death were 1.00, 0.97, and 1.04, respectively. These differences were not significant. In 2016, 3614 (39%) received quadrivalent vaccine, and 5700 (61%) received high-dose trivalent vaccine. The adjusted rates of first hospitalization by vaccine type were 8.71 and 8.04 per 100 patient-months, respectively, and the adjusted rates of death were 0.98 and 1.02, respectively. Receipt of high dose was associated with a significant reduction in hospitalization (hazard ratio, 0.93; 95% confidence interval, 0.86 to 1.00; P=0.04); there was no significant association with death. There was no significant heterogeneity of either association by age group or dialysis modality. Receipt of high-dose compared with standard dose influenza vaccine in 2016-2017 was associated with lower rates of hospitalization in patients on dialysis, although that was not seen in 2015-2016.

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

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. 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). 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. 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 safety of double versus standard dose of the seasonal influenza vaccine in solid-organ transplant recipients: A randomized controlled trial

BackgroundThe use of vaccines with higher doses of antigen is an attractive strategy to improve the immunogenicity of influenza vaccination in transplant recipients. However, the effect of vaccination with a double-dose (DD) containing 30 µg of antigen in this population remains unknown. MethodsWe performed a randomized controlled trial to compare the immunogenicity and safety of DD (30 µg) vs. standard dose (SD, 15 µg) of a trivalent inactivated influenza vaccine in kidney and liver transplant recipients. Immunogenicity was assessed by hemagglutination-inhibition assay. Vaccine response was defined as seroconversion to at least one viral strain 2 weeks after vaccination and seroprotection as a titer ≥40. ResultsSixty-three kidney and 16 liver transplant recipients were enrolled. Forty patients received the DD and 39 the SD vaccine. Overall, 40% of patients in the DD compared to 26% in the SD group (P = 0.174) responded to vaccine. In the DD arm, more patients were seroprotected to all viral strains after vaccination (88% vs 69%, P = 0.048). Post vaccination geometric mean titers of antibodies were 131.9 vs. 89.7 (P = 0.187) for H1N1, 185.4 vs. 138.7 (P = 0.182) for H3N2, and 96.6 vs. 68.8 (P = 0.081) for influenza B with the DD vs. SD. In both groups, most of the adverse events were mild and no vaccine-related severe adverse events were observed. ConclusionDouble-dose influenza vaccine is safe and may increase antibody response in transplant recipients. In this population, DD vaccination could be an alternative when high-dose vaccine is not available. NCT02746783.

PIN22 - An Economic Model To Estimate The Public Health Impact and Cost-Effectiveness of Vaccination of Seniors with Fluzone High Dose Influenza Vaccine in Australia

PIN22 - An Economic Model To Estimate The Public Health Impact and Cost-Effectiveness of Vaccination of Seniors with Fluzone High Dose Influenza Vaccine in Australia

279 - Randomized Trial Evaluating the Immunogenicity of High Dose vs. Standard Dose Influenza Vaccine in IBD Patients on Anti-TNF Monotherapy

279 - Randomized Trial Evaluating the Immunogenicity of High Dose vs. Standard Dose Influenza Vaccine in IBD Patients on Anti-TNF Monotherapy

Relationship between the frequency of influenza vaccination and cell-mediated immunity

Despite established guidelines for population-level assessments of immunity after vaccination, standard methods for individual-level analyses have not been established, limiting the ability to optimize vaccination strategies within a particular season. In this study, we evaluated changes in cell-mediated immunity (CMI) with respect to the number of influenza vaccine doses. In particular, the influenza vaccine was administered to 21 adults during the 2015–2016 season. IFN-γ production induced by the influenza vaccine antigens [A (H1N1), A (H3N2), B (Yamagata lineage), and B (Victoria lineage)] increased after the first dose of vaccination in 11, 10, 10, and 11 subjects, respectively. In 5 of 10 (H1N1), 4 of 10 (H3N2), 3 of 9 (Yamagata lineage), and 3 of 8 (Victoria lineage) subjects who did not exhibit an increase in IFN-γ production after the first dose, CMI was enhanced after the second dose. The production of IFN-γ increased after the first or second dose of the vaccine in 16, 14, 13, and 14 of the 21 subjects, respectively. The results of this study showed that two doses of the influenza vaccine effectively enhance CMI in subjects with primary vaccine failure.

Development and pilot testing of a text message vaccine reminder system for use during an influenza pandemic

ABSTRACTIn an influenza pandemic, two vaccine doses administered 21 days apart may be needed for individuals of all ages to achieve seroprotection. Achieving dose-series completion can be challenging even for routinely recommended vaccines. To prepare for a two-dose influenza pandemic vaccine campaign and promote dose-series completion and correct dosing intervals, CDC and its partners developed a text message-based vaccine reminder system to remind persons who receive a first dose of pandemic influenza vaccine to receive the second dose. Taking advantage of the high prevalence of cell phones in the United States, the system sent second-dose text message reminders and hyperlinks to educational information. The system was pilot tested from November 2015 to April 2016 among graduate public health students enrolled at four United States universities. Universities were selected based on convenience, and each university used a different recruitment method. Among 59 volunteers who pilot tested the system and completed a survey, 57 (92%) felt the system would be helpful during a pandemic. Forty (68%) respondents felt the information included in the messages was informative. Volunteers recommended including actionable ways to stay healthy during a pandemic, though specific suggestions varied. With further development, text reminder systems could be used to promote adherence to a two-dose regimen in a future pandemic, although audience-specific messaging and other complementary systems will likely be needed. Public and private partners can adapt and implement this tool in conjunction with their routine patient information systems to improve dose-series completion and ensure optimal protection during an influenza pandemic.

IgA polymerization contributes to efficient virus neutralization on human upper respiratory mucosa after intranasal inactivated influenza vaccine administration

ABSTRACTUnlike the current injectable influenza vaccines, intranasally administered influenza vaccines induce influenza virus-specific IgA antibodies in the local respiratory mucosa as well as IgG antibodies in the systemic circulation. Our previous study showed that after five volunteers underwent intranasal administration with inactivated H3N2 or H5N1 vaccines, their IgA antibodies on the upper respiratory tract were present as monomers, dimers, and multimers (trimers and tetramers). Moreover, the multimers associated with the highest virus neutralizing activity. However, it has remained elusive whether a more practical intranasal vaccination strategy could induce the high-performance IgA multimers in the nasal mucosa. In the present study, volunteers were administered with two doses of the intranasal trivalent whole-virus inactivated influenza vaccine and showed that in nasal wash samples the amount of multimeric IgA correlated positively with virus neutralizing titers, indicating that the multimeric IgA antibodies play an important role in the antiviral activity at the nasal mucosa. Surface plasmon resonance analysis of the binding dynamics of nasal wash derived IgA monomers, dimers, and multimers against recombinant trimeric influenza virus HA showed that sample fractions containing IgA multimers dissociated from HA less well than sample fractions without IgA multimers. Thus, IgA multimers may “stick” to the antigen more tightly than the other structures. In summary, intranasal administration of two doses of multivalent inactivated influenza vaccines induced multimeric IgA. Multimerization of mucosal IgA antibodies conferred higher neutralizing activity against viruses in the nasal mucosa, possibly by increasing their cohesion to virus antigens.

Effect of Influenza Vaccine in Patients With Kidney Transplant

BackgroundAmong infectious diseases, influenza is the most common cause of infection in Japan and worldwide. We aimed to evaluate the effect of influenza vaccination in kidney transplantation (KTx) recipients. MethodsWe retrospectively evaluated the records of 98 participants who underwent KTx at our institution between March 2009 and May 2016. All patients received tacrolimus or cyclosporine, mycophenolate mofetil, and methylprednisolone for maintenance immunosuppression after KTx. In accordance with the criteria of our institution, everolimus was administered for the maintenance of immunosuppression after KTx. We compared the rate of influenza infection during the 2016–2017 season (8 months, from October 2016-May 2017) between KTx patients treated with 1 or 2 doses of influenza vaccine (treatment group, n = 71) and KTx patients who did not receive a vaccine (nontreatment group, n = 27). ResultsAmong patient characteristics, only the prevalence of diabetes mellitus differed significantly between the groups (treatment group: 9.9%, 7 of 71 patients; nontreatment group: 29.6%, 8 of 21 patients; P = .02). Influenza infection occurred at similar rates in the 2 groups (treatment group, 5.63% 4 of 71 patients; nontreatment group: 3.70%, 1 of 27 patients; P = .70). ConclusionsAmong KTx patients managed in our institution, treatment with 1 or 2 doses of influenza vaccine did not reduce the rate of influenza infection in the 2016–2017 season, suggesting that influenza vaccination may currently be ineffective in KTx patients.

Safety and immunogenicity of a seasonal trivalent inactivated split influenza vaccine: a phase I randomized clinical trial in healthy Serbian adults

ABSTRACTThis study was a phase I double-blind, randomized, placebo-controlled trial to evaluate the safety and immunogenicity of a Serbian-produced seasonal trivalent split, inactivated influenza vaccine in healthy adults. The vaccine was manufactured in eggs by the Torlak Institute of Virology, Vaccines and Sera, Belgrade, Serbia and contained A/H1N1, A/H3N2 and B viruses. The clinical trial took place at the Clinical Center of Serbia in Belgrade. Sixty healthy volunteers, aged 18–45 years, were enrolled in the trial. On the day of immunization, volunteers were randomly assigned to receive either a single dose of the trivalent seasonal influenza vaccine (15 μg of hemagglutinin per strain) or placebo (phosphate-buffered saline). Subjects were monitored for adverse events through a clinical history and physical examination, and blood was taken for testing at screening and on day 8 to assess vaccine safety. Serum samples obtained before and 21 days after immunization were tested for influenza antibody titers using hemagglutination-inhibition (HAI) and microneutralization (MN) tests. No serious adverse events were reported. Pain and tenderness at the injection site were the most commonly reported symptoms in both vaccine and placebo groups. Overall, serum HAI responses of fourfold or greater magnitude were observed to H1, H3, and B antigen in 80%, 75%, and 70% of subjects, respectively. Seroprotection rates as measured by HAI were also high (100%, 100% and 86.67%, respectively, for H1, H3 and B). Thus, Torlak's seasonal trivalent influenza vaccine was not associated with adverse events, was well-tolerated and immunogenic. It should be further evaluated in clinical trials to provide sufficient safety and immunogenicity data for licensing in Serbia.

Progress in research of vaccination for patients with cancer

Due to the tumor malignancy or immunosuppressive treatment, patients with cancer in general are more susceptible to vaccine-preventable infections. The types, timing, dose of vaccination or even the immunization program for them may differ from those for the normal persons. At present, it is recommended to use inactivated vaccines for patients with cancer rather than attenuated live vaccines, Vaccinations should be avoided during immunosuppressive therapy; patients with cancer should receive double dosage of hepatitis B vaccines and two doses of inactivated influenza vaccines yearly. This paper summarizes the progress in clinical trials of vaccination for cancer patients in foreign countries, and provide reference for the development and implementation of vaccination strategy for cancer patients in China.

How close are countries of the WHO European Region to achieving the goal of vaccinating 75% of key risk groups against influenza? Results from national surveys on seasonal influenza vaccination programmes, 2008/2009 to 2014/2015

BackgroundInfluenza vaccination is recommended especially for persons at risk of complications. In 2003, the World Health Assembly urged Member States (MS) to increase vaccination coverage to 75% among older persons by 2010. ObjectiveTo assess progress towards the 2010 vaccination goal and describe seasonal influenza vaccination recommendations in the World Health Organization (WHO) European Region. MethodsData on seasonal influenza vaccine recommendations, dose distribution, and target group coverage were obtained from two sources: European Union and European Economic Area MS data were extracted from influenza vaccination surveys covering seven seasons (2008/2009–2014/2015) published by the Vaccine European New Integrated Collaboration Effort and European Centre for Disease Prevention and Control. For the remaining WHO European MS, a separate survey on policies and uptake for all seasons (2008/2009–2014/2015) was distributed to national immunization programmes in 2015. ResultsData was available from 49 of 53 MS. All but two had a national influenza vaccination policy. High-income countries distributed considerably higher number of vaccines per capita (median; 139.2 per 1000 population) compared to lower-middle-income countries (median; 6.1 per 1000 population). Most countries recommended vaccination for older persons, individuals with chronic disease, healthcare workers, and pregnant women. Children were included in < 50% of national policies. Only one country reached 75% coverage in older persons (2014/2015), while a number of countries reported declining vaccination uptake. Coverage of target groups was overall low, but with large variations between countries. Vaccination coverage was not monitored for several groups. ConclusionsDespite policy recommendations, influenza vaccination uptake remains suboptimal. Low levels of vaccination is not only a missed opportunity for preventing influenza in vulnerable groups, but could negatively affect pandemic preparedness. Improved understanding of barriers to influenza vaccination is needed to increase uptake and reverse negative trends. Furthermore, implementation of vaccination coverage monitoring is critical for assessing performance and impact of the programmes.

The effect of frailty on HAI response to influenza vaccine among community-dwelling adults ≥ 50 years of age

ABSTRACTThe immune response to vaccine antigens is less robust in older adults because of changes in the aging immune system. Frailty, the multi-dimensional syndrome marked by losses in function and physiological reserve, is increasingly prevalent with advancing age. Frailty accelerates this immunosenescence but the consequence of frailty on immune response specific to influenza vaccine among older adults, is mixed. An observational, prospective study of 114 adults was conducted in the fall of 2013 to assess the association of physical frailty with immune response to standard dose influenza vaccine in community-dwelling adults ≥ 50 years of age. Participants were stratified by age (<65 years and ≥65 years), and vaccine strain (Influenza A/H1N1, A/H3N2 and B) was analyzed separately adjusting for body mass index (BMI) and baseline log2 hemagglutination inhibition (HAI) titers. Overall, immune responses were lower among those ≥65 years of age than those <65 years. Among those ≥65 years there were no significant differences between frail and non-frail individuals in seroprotection or seroconversion for any influenza strain. Frail individuals <65 years of age compared with non-frail individuals were more likely to be seroprotected and to seroconvert post vaccination. Linear regression models show the same pattern of significant differences between frail and non-frail for those <65 years but no significant differences between frailty groups for those ≥65 years. Additional research may elucidate the reasons for the differences observed between younger frail and non-frail adults.

Conventional influenza vaccines influence the performance of a universal influenza vaccine in mice

Universal influenza vaccines are designed to protect against diverse strains of influenza virus. Preclinical testing of new vaccine candidates is usually done in naïve animals, despite intended use in the human population with its varied immune history including responses to previous vaccinations. As an approach more relevant to human use, we tested a candidate universal influenza vaccine in mice with a history of conventional vaccination. Female BALB/c mice were given two intramuscular doses of inactivated influenza vaccine (IIV) or diphtheria and tetanus toxoids vaccine (DT), one month apart. Another group was given two intranasal doses of live attenuated influenza virus (LAIV). One month after the second dose, mice were given the universal influenza vaccine: recombinant adenoviruses expressing influenza A nucleoprotein (A/NP) and matrix 2 (M2) (A/NP + M2-rAd). Immune responses to universal vaccine antigens A/NP and M2 were assessed by ELISA and interferon-γ ELISPOT. Protection was tested by challenge with mouse-adapted A/FM/1/47 (H1N1) and monitoring for weight loss and survival. Universal vaccine performance was enhanced, inhibited or unaffected by particular prior vaccinations. Mice given Afluria IIV and LAIV had greater antibody and T-cell response to A/NP than mice without prior vaccination, providing examples of enhanced A/NP + M2-rAd performance. Though Fluvirin IIV partially inhibited, the universal vaccine still provided considerable protection unlike conventional vaccination. Fluzone IIV and DT had no effect on A/NP + M2-rAd performance. Thus our results demonstrate that universal vaccine candidate A/NP + M2-rAd was at least partially effective in mice with diverse prior histories. However, the degree of protection and nature of the immune responses may be affected by a history of conventional vaccination and suggests that performance in humans would be influenced by immune history.

The safety of influenza vaccine in clinically cured leprosy patients in China

ABSTRACTBackground: Leprosy is an infectious disease caused by the bacterium Mycobacterium leprae. Influenza vaccine is an important influenza prevention strategy and the preparations used display good safety and tolerability profiles. But the safety of applying influenza vaccine on the clinical cured leprosy patients is unclear.Methods: We conducted an observational clinical study, in Wuhan between November 15, 2016 and March 1, 2017. Two groups of participants ≥50 years of age received a 0.5 ml dose of the inactivated split-virion trivalent influenza vaccine and a follow-up 28 days observation of any solicited and unsolicited adverse events.Results: A total of 134 subjects were included in the study. The total rate of reactogenicity was 5.4% [2/37] in leprosy group and 15.5% [15/ 97] in control group, the difference of reactogenicity between two groups was not significant (p = 0.1522). For solicited injection-sites adverse events (AEs), 12.4% [12/ 97] participants in the control group reported of itching, pain, erythema, swelling or induration, and no participants in leprosy group reported of any solicited injection-sites AEs. For solicited systemic AEs, 7.2% [7 / 97] participants in the control group reported of fever, malaise or headache, and 2.7% [1 / 37] participants in the leprosy group reported of fever, statistic result showed that the difference was not significant (p = 0.4438). Unsolicited AEs was reported by one male aged 76, 4 hours after vaccination administration, his plantar ulcer area began bleeding. All AEs were grade 1 or grade 2, and no recurrence of lepra reaction, AEs leading to early withdrawal from the study, or deaths were reported in this study.Conclusions: To our knowledge, the present study is the first clinical study to evaluate the safety of influenza vaccine in clinically cured leprosy patients. We concluded that clinically cured leprosy patients are relatively safe for influenza vaccine. More importantly, our study make a positive and scientific efforts to eradicate discrimination on leprosy. In our study, we described a patient with plantar ulcer undergoing bleeding for 4 hours after vaccine administration. Based on evidence we have, we interpret that this adverse event may probably associated with vaccine, and patients with ulcer and leprosy need intensive attention after vaccines administration.

Seasonal and pandemic influenza: global fatigue versus global preparedness

Seasonal and pandemic influenza: global fatigue versus global preparedness

Booster influenza vaccination confers additional immune responses in an elderly, rural community-dwelling population

This study aimed to examine the effects of a booster vaccination in elderly people using 2 doses of trivalent inactivated influenza vaccine during the 2012-2013 influenza epidemic. Seroprotection rates against the A(H1N1)pdm09 strain in younger elderly people (aged 61-75 years) and the A(H3N2) and B strains in both younger elderly people (aged 61-75 years) as well as very elderly people (aged 76-102 years) did not decrease at 22 weeks after vaccination. This approach confers long-lasting antibody responses and may be useful in clinical practice.

Review of maternal immunisation during pregnancy: focus on pertussis and influenza.

Seasonal influenza and pertussis infections are known to be significant causes of morbidity and mortality in neonates and infants worldwide. Influenza has also been associated with severe complications in pregnant women and after delivery. The most efficient and safe strategy to protect mothers and their offspring is maternal immunisation during pregnancy. The maternal antibodies thus acquired are transferred to the fetus as of the second trimester and confer passive immunity until the first infant immunisations. Therefore, it is strongly advised to administer booster doses of seasonal influenza and pertussis vaccines specifically during pregnancy. Influenza vaccines can be given at any time-point during pregnancy and pertussis vaccines after the first trimester. Both need a minimum interval of 14 days between immunisation and delivery and, especially for pertussis, early immunisation has been shown to increase neonatal antibody titres. Healthcare workers play a crucial role in vaccine uptake. This article aims to review the recommendations for maternal influenza and pertussis immunisation, and their physiological rationale, safety and benefit.

Vaccine effectiveness against influenza-associated hospitalization among children aged &amp;lt; 13 years using a hospital-based surveillance system in Minnesota, 2013 – 2016

BackgroundDue to marked variability in circulating influenza viruses each year, annual evaluation of the vaccine’s effectiveness against severe outcomes is essential. We used the Minnesota Department of Health’s (MDH) Severe Acute Respiratory Illness (SARI) surveillance to evaluate vaccine effectiveness (VE) against influenza-associated hospitalization over three influenza seasons.MethodsResidual respiratory specimens from patients admitted with SARI were sent to the MDH laboratory for influenza RT-PCR testing. Medical records were reviewed to collect patient data. Vaccination history was verified using the state immunization registry. We included patients aged ≥6 months to < 13 years, after which immunization reporting is not required, hospitalized from the earliest influenza detection after July through April each year. We defined vaccinated patients as those ≥1 dose of influenza vaccine in the current season. Children aged < 9 years with no history of vaccination were considered vaccinated if 2 were doses given a month apart. Partially vaccinated children were excluded. We estimated VE as 1 minus the adjusted odds ratio (x100%) of influenza vaccination among influenza cases vs. negative controls, controlling for age, race, days from onset to admission, comorbidities, and admission month.ResultsAmong 2198 SARI patients, 763 (35%) were vaccinated for influenza, 180 (8.2%) were partially vaccinated, and 1255 (57%) were unvaccinated. Influenza was detected among 202 (9.2%) children, and significantly more frequently among children aged ≥5 years (17%) compared with younger children (7.4%). The adjusted VE in 2013–14 was 68% (95% Confidence Interval: 34, 85), but was non-significant during the 2014–15 and 2015–16 seasons (Figure). Estimates of VE by influenza A subtypes varied substantially by year; VE against influenza B viruses was significant, but could not be stratified by year. VE was impacted when live attenuated influenza vaccine recipients were excluded.ConclusionWe report moderately high influenza VE in 2013–14 and a point estimate higher than other published estimates from outpatient data in 2014–15. These results, underscore the importance of influenza vaccination to prevent severe outcomes such as hospitalization.Disclosures All authors: No reported disclosures.