Establishment of human post-vaccination SARS-CoV-2 standard reference sera.

There is a critical need to understand the effectiveness of serum elicited by different SARS-CoV-2 vaccines against SARS-CoV-2 variants. We describe the generation of reference reagents comprised of post-vaccination sera from recipients of different primary vaccines with or without different vaccine booster regimens in order to allow standardized characterization of SARS-CoV-2 neutralization in vitro. We prepared and pooled serum obtained from donors who received a either primary vaccine series alone, or a vaccination strategy that included primary and boosted immunization using available SARS-CoV-2 mRNA vaccines (BNT162b2, Pfizer and mRNA-1273, Moderna), replication-incompetent adenovirus type 26 vaccine (Ad26.COV2·S, Johnson and Johnson), or recombinant baculovirus-expressed spike protein in a nanoparticle vaccine plus Matrix-M adjuvant (NVX-CoV2373, Novavax). No subjects had a history of clinical SARS-CoV-2 infection, and sera were screened with confirmation that there were no nucleocapsid antibodies detected to suggest natural infection. Twice frozen sera were aliquoted, and serum antibodies were characterized for SARS-CoV-2 spike protein binding (estimated WHO antibody binding units/ml), spike protein competition for ACE-2 binding, and SARS-CoV-2 spike protein pseudotyped lentivirus transduction. These reagents are available for distribution to the research community (BEI Resources), and should allow the direct comparison of antibody neutralization results between different laboratories. Further, these sera are an important tool to evaluate the functional neutralization activity of vaccine-induced antibodies against emerging SARS-CoV-2 variants of concern. IMPORTANCE: The explosion of COVID-19 demonstrated how novel coronaviruses can rapidly spread and evolve following introduction into human hosts. The extent of vaccine- and infection-induced protection against infection and disease severity is reduced over time due to the fall in concentration, and due to emerging variants that have altered antibody binding regions on the viral envelope spike protein. Here, we pooled sera obtained from individuals who were immunized with different SARS-CoV-2 vaccines and who did not have clinical or serologic evidence of prior infection. The sera pools were characterized for direct spike protein binding, blockade of virus-receptor binding, and neutralization of spike protein pseudotyped lentiviruses. These sera pools were aliquoted and are available to allow inter-laboratory comparison of results and to provide a tool to determine the effectiveness of prior vaccines in recognizing and neutralizing emerging variants of concern.

Immunogenicity and safety of varying dosages of a fifth-wave influenza A/H7N9 inactivated vaccine given with and without AS03 adjuvant in healthy adults.

BACKGROUND: Human infections with the avian influenza A(H7N9) virus were first reported in China in 2013 and continued to occur in annual waves. In the 2016/2017 fifth wave, Yangtze River Delta (YRD) lineage viruses, which differed antigenically from those of earlier waves, predominated. METHODS: In this phase 2 double-blinded trial we randomized 720 adults ≥ 19 years of age to receive two injections of a YRD lineage inactivated A/Hong Kong/125/2017 fifth-wave H7N9 vaccine, given 21 days apart, at doses of 3.75, 7.5, and 15 µg of hemagglutinin (HA) with AS03A adjuvant and at doses of 15 and 45 µg of HA without adjuvant. RESULTS: Two doses of adjuvanted vaccine were required to induce HA inhibition (HI) antibody titers ≥ 40 in most participants. After two doses of the 15 µg H7N9 formulation, given with or without AS03 adjuvant, the proportion achieving a HI titer ≥ 40 against the vaccine strain at 21 days after the second vaccination was 65 % (95 % CI, 57 %-73 %) and 0 % (95 % CI, 0 %-4%), respectively. Among those who received two doses of the 15 µg adjuvanted formulation the proportion with HI titer ≥ 40 at 21 days after the second vaccination was 76 % (95 % CI, 66 %-84 %) in those 19-64 years of age and 49 % (95 % CI, 37 %-62 %) in those ≥ 65 years of age. Responses to the adjuvanted vaccine formulations did not vary by HA content. Antibody responses declined over time and responses against drifted H7N9 strains were diminished. Overall, the vaccines were well tolerated but, as expected, adjuvanted vaccines were associated with more frequent solicited systemic and local adverse events. CONCLUSIONS: AS03 adjuvant improved the immune responses to an inactivated fifth-wave H7N9 influenza vaccine, particularly in younger adults, but invoked lower responses to drifted H7N9 strains. These findings may inform future influenza pandemic preparedness strategies.

Immunogenicity of a 2-Dose Regimen of Moderna mRNA Beta/Omicron BA.1 Bivalent Variant Vaccine Boost in a Randomized Clinical Trial.

We compared the serologic responses of 1 dose versus 2 doses of a variant vaccine (Moderna mRNA-1273 Beta/Omicron BA.1 bivalent vaccine) in adults. A 2-dose boosting regimen with a variant vaccine did not increase the magnitude or the durability of the serological responses compared to a single variant vaccine boost.

Comparison of bivalent and monovalent SARS-CoV-2 variant vaccines: the phase 2 randomized open-label COVAIL trial.

Vaccine protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection wanes over time, requiring updated boosters. In a phase 2, open-label, randomized clinical trial with sequentially enrolled stages at 22 US sites, we assessed safety and immunogenicity of a second boost with monovalent or bivalent variant vaccines from mRNA and protein-based platforms targeting wild-type, Beta, Delta and Omicron BA.1 spike antigens. The primary outcome was pseudovirus neutralization titers at 50% inhibitory dilution (ID50 titers) with 95% confidence intervals against different SARS-CoV-2 strains. The secondary outcome assessed safety by solicited local and systemic adverse events (AEs), unsolicited AEs, serious AEs and AEs of special interest. Boosting with prototype/wild-type vaccines produced numerically lower ID50 titers than any variant-containing vaccine against all variants. Conversely, boosting with a variant vaccine excluding prototype was not associated with decreased neutralization against D614G. Omicron BA.1 or Beta monovalent vaccines were nearly equivalent to Omicron BA.1 + prototype or Beta + prototype bivalent vaccines for neutralization of Beta, Omicron BA.1 and Omicron BA.4/5, although they were lower for contemporaneous Omicron subvariants. Safety was similar across arms and stages and comparable to previous reports. Our study shows that updated vaccines targeting Beta or Omicron BA.1 provide broadly crossprotective neutralizing antibody responses against diverse SARS-CoV-2 variants without sacrificing immunity to the ancestral strain. ClinicalTrials.gov registration: NCT05289037 .

Immunogenicity of a Two Dose Regimen of Moderna mRNA Beta/Omicron BA.1 Bivalent Variant Vaccine Boost in a Randomized Clinical Trial.

In this brief report, we compare the magnitude and durability of the serologic response of one versus two doses (separated by 56 days) of a variant vaccine (Moderna mRNA-1273 Beta/Omicron BA.1 bivalent vaccine) in adults.

Research unit network (RUN) as a learning research system.

The clinical research units (CRUs) are one of the main spaces where both translational research and science take place. However, there is a lack of information about both best practices for CRU operations and, ultimately, benchmarks to evaluate CRU performance. The Research Unit Network (RUN) was created with the purpose to enable direct communication and collaboration among CRUs. An online survey was administered to further illustrate the functionality and impact of RUN. Thirty-one individual survey responses (39.2%) were included in the final analysis. The members value RUN monthly meetings (87.1%) as the most useful aspect of this network and CRU budgeting (67.7%) and staffing (61.3%) were the most relevant topics discussed. This is followed by EPIC - Research (58.1%), delegation of authority logs, unit signatures, and policies (51.6%), COVID-19 pandemic response (41.9%), the implementation of clinical trial management system (29.0%), and protocol deviations (19.4%). The intermediate goal of RUN is to identify best practices CRUs are establishing, implementing, and sharing these experiences with the goal to adopt them in different CRUs. The network's long-term goal is to establish standard benchmarks that can be used for evaluating the performance of CRUs across the nation.

Immunogenicity of the BA.1 and BA.4/BA.5 SARS-CoV-2 Bivalent Boosts: Preliminary Results from the COVAIL Randomized Clinical Trial.

In a randomized clinical trial, we compare early neutralizing antibody responses after boosting with bivalent SARS-CoV-2 mRNA vaccines based on either BA.1 or BA.4/BA.5 Omicron spike protein combined with wildtype spike. Responses against SARS-CoV-2 variants exhibited the greatest reduction in titers against currently circulating Omicron subvariants for both bivalent vaccines.

Immunogenicity of the BA.1 and BA.4/BA.5 Severe Acute Respiratory Syndrome Coronavirus 2 Bivalent Boosts: Preliminary Results From the COVAIL Randomized Clinical Trial.

In a randomized clinical trial, we compare early neutralizing antibody responses after boosting with bivalent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger RNA (mRNA) vaccines based on either BA.1 or BA.4/BA.5 Omicron spike protein combined with wild-type spike. Responses against SARS-CoV-2 variants exhibited the greatest reduction in titers against currently circulating Omicron subvariants for both bivalent vaccines.

Safety and Immunogenicity of a monovalent inactivated influenza A/H5N8 virus vaccine given with and without AS03 or MF59 adjuvants in healthy adults.

BACKGROUND: Avian influenza A/H5N8 virus infections have been circulating widely in wild and domestic bird populations with transmission to a few human poultry workers. This phase 1, randomized, blinded trial evaluated the safety and immunogenicity of a monovalent inactivated influenza A/H5N8 virus vaccine (H5N8 IIV) given with and without AS03 or MF59 adjuvants. METHODS: 275 healthy adults, ages 19-64 years, were randomized to one of five groups to receive two doses of 15 µg unadjuvanted influenza A/gyrfalcon/Washington/41088-6/2014(H5N8) (clade 2.3.4.4c) virus vaccine or two doses of 7.5 or 15 µg of vaccine adjuvanted with AS03 or MF59. Immunogenicity was assessed through 21 days following the second dose of vaccine using hemagglutination inhibition (HAI) and microneutralization (MN) assays for the homologous influenza A/H5N8 and three heterologous influenza A/H5 viruses. Safety was assessed through 1 year. RESULTS: The vaccines were well tolerated. Only modest immune responses were seen following receipt of a single dose of vaccine. Seroprotection (HAI titers ≥40) was more common in groups that received AS03 plus 7.5 or 15 µg of vaccine (89% and 93%, respectively) compared to the MF59-adjuvanted groups (56% and 73%), while unadjuvanted vaccine showed a poor response (27%). Higher antigen content resulted in modestly improved immune responses. HAI and MN GMTs and seroconversion rates were low across all study groups for all three heterologous strains of influenza A/H5 virus. CONCLUSIONS: AS03 or MF59-adjuvanted H5N8 IIV generated strong immunogenic responses following two doses. There was poor cross-reactivity for the three antigenically drifted H5N1 strains tested.

Population Pharmacokinetics of Piperacillin/Tazobactam Across the Adult Lifespan.

BACKGROUND AND OBJECTIVE: Piperacillin/tazobactam is one of the most frequently used antimicrobials in older adults. Using an opportunistic study design, we evaluated the pharmacokinetics of piperacillin/tazobactam as a probe drug to evaluate changes in antibacterial drug exposure and dosing requirements, including in older adults. METHODS: A total of 121 adult patients were included. The population pharmacokinetic models that best characterized the observed plasma concentrations of piperacillin and tazobactam were one-compartment structural models with zero-order input and linear elimination. RESULTS: Among all potential covariates, estimated creatinine clearance had the most substantial impact on the elimination clearance for both piperacillin and tazobactam. After accounting for renal function and body size, there was no remaining impact of frailty on the pharmacokinetics of piperacillin and tazobactam. Monte Carlo simulations indicated that renal function had a greater impact on the therapeutic target attainment than age, although these covariates were highly correlated. Frailty, using the Canadian Study of Health and Aging Clinical Frailty Scale, was assessed in 60 patients who were ≥ 65 years of age. CONCLUSIONS: The simulations suggested that adults ≤ 50 years of age infected with organisms with higher minimum inhibitory concentrations may benefit from continuous piperacillin/tazobactam infusions (12 g/day of piperacillin component) or extended infusions of 4 g every 8 hours. However, for a target of 50% fT + minimum inhibitory concentration, dosing based on renal function is generally preferable to dosing by age, and simulations suggested that patients with creatinine clearance ≥ 120 mL/min may benefit from infusions of 4 g every 8 hours for organisms with higher minimum inhibitory concentrations.

SARS-CoV-2 Variant Vaccine Boosters Trial: Preliminary Analyses.

Background: Protection from SARS-CoV-2 vaccines wanes over time and is compounded by emerging variants including Omicron subvariants. This study evaluated safety and immunogenicity of SARS-CoV-2 variant vaccines. Methods: This phase 2 open-label, randomized trial enrolled healthy adults previously vaccinated with a SARS-CoV-2 primary series and a single boost. Eligible participants were randomized to one of six Moderna COVID19 mRNA vaccine arms (50µg dose): Prototype (mRNA-1273), Omicron BA.1+Beta (1 or 2 doses), Omicron BA.1+Delta, Omicron BA.1 monovalent, and Omicron BA.1+Prototype. Neutralization antibody titers (ID 50 ) were assessed for D614G, Delta, Beta and Omicron BA.1 variants and Omicron BA.2.12.1 and BA.4/BA.5 subvariants 15 days after vaccination. Results: From March 30 to May 6, 2022, 597 participants were randomized and vaccinated. Median age was 53 years, and 20% had a prior SARS-CoV-2 infection. All vaccines were safe and well-tolerated. Day 15 geometric mean titers (GMT) against D614G were similar across arms and ages, and higher with prior infection. For uninfected participants, Day 15 Omicron BA.1 GMTs were similar across Omicron-containing vaccine arms (3724-4561) and higher than Prototype (1,997 [95%CI:1,482-2,692]). The Omicron BA.1 monovalent and Omicron BA.1+Prototype vaccines induced a geometric mean ratio (GMR) to Prototype for Omicron BA.1 of 2.03 (97.5%CI:1.37-3.00) and 1.56 (97.5%CI:1.06-2.31), respectively. A subset of samples from uninfected participants in four arms were also tested in a different laboratory at Day 15 for neutralizing antibody titers to D614G and Omicron subvariants BA.1, BA.2.12.2 and BA.4/BA.5. Omicron BA.4/BA.5 GMTs were approximately one third BA.1 GMTs (Prototype 517 [95%CI:324-826] vs. 1503 [95%CI:949-2381]; Omicron BA.1+Beta 628 [95%CI:367-1,074] vs. 2125 [95%CI:1139-3965]; Omicron BA.1+Delta 765 [95%CI:443-1,322] vs. 2242 [95%CI:1218-4128] and Omicron BA.1+Prototype 635 [95%CI:447-903] vs. 1972 [95%CI:1337-2907). Conclusions: Higher Omicron BA.1 titers were observed with Omicron-containing vaccines compared to Prototype vaccine and titers against Omicron BA.4/BA.5 were lower than against BA.1 for all candidate vaccines. Clinicaltrialsgov: NCT05289037.

Five Percent Monolaurin Vaginal Gel for the Treatment of Bacterial Vaginosis: A Randomized Placebo-Controlled Trial.

OBJECTIVE: The aim of the study was to test the hypothesis that 5% monolaurin vaginal gel, a naturally occurring monoglyceride shown to have antimicrobial effects on vaginal pathogens without affecting Lactobacillus species, cures bacterial vaginosis (BV). MATERIALS AND METHODS: This was a multicenter, double-blinded, randomized controlled trial comparing 5% monolaurin vaginal gel to vehicle placebo (glycol-based) gel administered twice daily for 3 days. Nonpregnant, nonbreastfeeding women between ages 18 and 50 years were recruited and BV confirmed. Primary outcome was clinical cure assessed by resolution of all 4 Amsel criteria. Secondary outcomes included safety and tolerability assessed by solicited urogenital adverse events. Exploratory outcomes included colony counts for vaginal microbes associated with healthy vaginal flora (Lactobacillus species) and the dysbiosis often associated with BV (Gardnerella species and Mobiluncus species). A 2:1 test article to placebo randomization scheme was planned. RESULTS: One hundred nine women participated with 73 randomized to the treatment arm and 36 to the placebo arm. There was no significant difference in clinical cure for BV (p = .42) with 17% of the monolaurin group and 25% of the placebo group achieving clinical cure. Lactobacilli species counts increased in the monolaurin group compared with placebo (1.0 × 10 vs -5.2 × 10). Two thirds of both groups reported solicited urogenital adverse events, but these were mild to moderate with no significant difference between groups (p = .24). CONCLUSIONS: Monolaurin was no more clinically or microbiologically effective than placebo in curing BV. Future research should explore whether monolaurin may be used to increase Lactobacilli species.

High dose trivalent influenza vaccine compared to standard dose vaccine in patients with rheumatoid arthritis receiving TNF-alpha inhibitor therapy and healthy controls: Results of the DMID 10-0076 randomized clinical trial.

INTRODUCTION: Subjects with rheumatoid arthritis (RA) receiving tumor necrosis factor-inhibiting (TNFi) therapies are at risk for severe influenza, and may respond less well to influenza vaccine. We examined the safety and immunogenicity of high dose influenza vaccine (HD) compared to standard dose vaccine (SD) in participants with RA receiving stable TNFi. METHODS: A randomized, double-blinded, Phase II study was conducted in adults with RA receiving TNFi, and healthy, gender and age-matched control subjects. Participants were immunized with HD (Sanofi Pasteur Fluzone High Dose [60 mcg × 3 strains]) or SD (Sanofi Pasteur Fluzone® [15 mcg × 3 strains]) intramuscularly (IM). A self-administered memory aid recorded temperature and systemic and local adverse events (AEs) for 8 days, and safety was evaluated and serum obtained to measure HAI activity on days 7, 21 and 180 days following vaccination. RESULTS: A greater proportion of RA subjects who received HD seroconverted at day 21 compared to SD, although this was not statistically significant. GMT antibody responses in RA subjects who received HD compared to SD were greater for all strains on day 21, and this was significant for H1N1. Seroconversion rates and GMT values were not different between RA subjects and control subjects. There were no safety concerns for HD or SD in RA subjects, and RA-related symptoms did not differ between SD and HD recipients by a RA-symptom questionnaire (RAPID 3). CONCLUSIONS: TNF-inhibitor therapy in people with RA did not appear to influence the immunogenicity of either SD or HD. Influenza seroconversion and GMT values were higher among RA subjects receiving HD compared to SD; however, differences were small and a larger study is needed to validate these findings. Given the apparent risk of increased influenza-related morbidity and mortality among immune compromised subjects, the higher GMT values generated by HD may be beneficial.

Tularemia vaccine: Safety, reactogenicity, "Take" skin reactions, and antibody responses following vaccination with a new lot of the Francisella tularensis live vaccine strain - A phase 2 randomized clinical Trial.

BACKGROUND: Tularemia is caused by Francisella tularensis, a gram-negative bacterium that has been weaponized as an aerosol. For protection of personnel conducting biodefense research, the United States Army required clinical evaluation of a new lot of tularemia live vaccine strain manufactured in accordance with Current Good Manufacturing Practices. METHODS: A phase 2 randomized clinical trial compared the new lot (DVC-LVS) to the existing vaccine that has been in use for decades (USAMRIID-LVS). The vaccines were delivered by scarification to 228 participants. Safety, reactogenicity, take and/or antibody levels were assessed on days 0, 1, 2, 8, 14, 28, 56, and 180. PRINCIPAL RESULTS: Both vaccines were safe and had acceptable reactogenicity profiles during six months of follow-up. There were no serious or grade 3 and 4 laboratory adverse events. Moderate systemic reactogenicity (mostly headache or feeling tired) was reported by ∼23% of participants receiving either vaccine. Injection site reactogenicity was mostly mild itchiness and pain. The frequencies of vaccine take skin reactions were 73% (95% CI, 64, 81) for DVC-LVS and 80% (95% CI, 71, 87) for USAMRIID-LVS. The 90% CI for the difference in proportions was -6.9% (-16.4, 2.6). The rates of seroconversion measured by microagglutination assay on days 28 or 56 were 94% (95% CI, 88, 98; n=98/104) for DVC-LVS and 94% (95% CI, 87, 97; n=103/110) for USAMRIID-LVS (p=1.00). Day 14 sera revealed more rapid seroconversion for DVC-LVS relative to USAMRIID-LVS: 82% (95% CI, 73, 89) versus 55% (95% CI, 45, 65), respectively (p<0.0001). MAJOR CONCLUSIONS: The DVC-LVS vaccine had similar safety, reactogenicity, take and antibody responses compared to the older USAMRIID vaccine, and was superior for early (day 14) antibody production. Vaccination take was not a sensitive surrogate for seroconversion in a multi-center study where personnel at five research clinics performed assessments. ClinicalTrials.gov identifier NCT01150695.

CD11a and CD49d enhance the detection of antigen-specific T cells following human vaccination.

BACKGROUND: Determining the efficacy of human vaccines that induce antigen-specific protective CD4 T cell responses against pathogens can be particularly challenging to evaluate. Surface expression of CD11a and CD49d has been shown to identify antigen-specific CD4 T cells against viral pathogens in mice. We hypothesized that CD11a and CD49d would also serve as markers of human antigen-specific T cells responding to vaccination. METHODS: A phase I vaccine trial enabled us to evaluate a novel gating strategy based on surface expression of CD11a and CD49d as a means of detecting antigen-specific, cytokine producing CD4 and CD8 T cells induced after vaccination of naïve individuals against leishmaniasis. Three study groups received LEISH-F3 recombinant protein combined with either squalene oil-in-water emulsion (SE) alone, SE with the synthetic TLR-4 ligand glucopyranosyl lipid adjuvant (GLA-SE), or SE with Salmonella minnesota-derived monophosphoryl lipid A (MPL-SE). Individuals were given 3 vaccine doses, on days 0, 28 and 168. RESULTS: Starting after the first vaccine dose, the frequency of both CD11ahiCD49d+ CD4 and CD11ahiCD49d+ CD8 T cells significantly increased over time throughout the 24-week trial. To confirm the role of CD11ahiCD49d+ expression in the identification of the antigen-specific T cells, cytokine production was measured following LEISH-F3 stimulation. All of the IFN-γ, TNF-α, and IL-2 producing cells were found within the CD11ahiCD49d+ population. CONCLUSIONS: Our results suggest that the change in the frequency of CD11ahiCD49d+ T cells can be used to track antigen-specific CD4 and CD8 T cell responses following T cell-targeted vaccination.

Safety and immunogenicity of a modified vaccinia Ankara vaccine using three immunization schedules and two modes of delivery: A randomized clinical non-inferiority trial.

INTRODUCTION: To guide the use of modified vaccinia Ankara (MVA) vaccine in response to a release of smallpox virus, the immunogenicity and safety of shorter vaccination intervals, and administration by jet injector (JI), were compared to the standard schedule of administration on Days 1 and 29 by syringe and needle (S&N). METHODS: Healthy adults 18-40years of age were randomly assigned to receive MVA vaccine subcutaneously by S&N on Days 1 and 29 (standard), Days 1 and 15, or Days 1 and 22, or to receive the vaccine subcutaneously by JI on Days 1 and 29. Blood was collected at four time points after the second vaccination for plaque reduction neutralization test (PRNT) (primary endpoint) and ELISA (secondary endpoint) antibody assays. For each subject, the peak PRNT (or ELISA) titer was defined by the highest PRNT (or ELISA) titer among all available measurements post second vaccination. Non-inferiority of a non-standard arm compared to the standard arm was met if the upper limit of the 98.33% confidence interval of the difference in the mean log2 peak titers between the standard and non-standard arm was less than 1. RESULTS: Non-inferiority of the PRNT antibody response was not established for any of the three non-standard study arms. Non-inferiority of the ELISA antibody response was established for the Day 1 and 22 compressed schedule and for administration by JI. Solicited local reactions, such as redness and swelling, tended to be more commonly reported with JI administration. Four post-vaccination hypersensitivity reactions were observed. CONCLUSIONS: Evaluations of the primary endpoint of PRNT antibody responses do not support alternative strategies of administering MVA vaccine by S&N on compressed schedules or administration by JI on the standard schedule. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01827371.

Priming Vaccination With Influenza Virus H5 Hemagglutinin Antigen Significantly Increases the Duration of T cell Responses Induced by a Heterologous H5 Booster Vaccination.

BACKGROUND: Influenza A(H5N1) virus and other avian influenza virus strains represent major pandemic threats. Like all influenza A virus strains, A(H5N1) viruses evolve rapidly. Innovative immunization strategies are needed to induce cross-protective immunity. METHODS: Subjects primed with clade 1 H5 antigen, with or without adjuvant, and H5-naive individuals were boosted with clade 2 H5 antigen. The impact of priming on T cells capable of both proliferation and cytokine production after antigen restimulation was assessed. RESULTS: Subjects previously vaccinated with clade 1 H5 antigen developed significantly enhanced clade 2 H5 cross-reactive T cell responses detectable 6 months after vaccination with clade 2 H5 antigen. Priming dose (15 µg vs 45 or 90 µg) had no effect on magnitude of heterotypic H5 T cell responses. In contrast, age at priming negatively modulated both the magnitude and duration of heterotypic H5 T cell responses. Elderly subjects developed significantly less heterotypic H5 T cell boosting, predominantly for T cells capable of cytokine production. Adjuvant had a positive albeit weaker effect than age. The magnitude of CD4(+) interferon-γ producing T cells correlated with H5 antibody responses. CONCLUSIONS: H5 heterotypic priming prior to onset of an A(H5N1) pandemic may increase magnitude and duration of immunity against a newly drifted pandemic H5 virus.

Increased Mortality Rates Associated with Staphylococcus aureus and Influenza Co-infection, Maryland and Iowa, USA(1).

We retrospectively analyzed data for 195 respiratory infection patients who had positive Staphyloccocus aureus cultures and who were hospitalized in 2 hospitals in Iowa and Maryland, USA, during 2003-2009. Odds for death for patients who also had influenza-positive test results were >4 times higher than for those who had negative influenza test results.

Cell mediated immune responses following revaccination with an influenza A/H5N1 vaccine.

PURPOSE: The study aims were to determine whether inactivated influenza A/H5N1 vaccine administration elicited cell mediated immune (CMI) responses and the impact of adjuvant, vaccine dose and subject age on these responses. METHODS: Adults who were previously primed with either adjuvanted or unadjuvanted, inactivated, A/H5N1/Vietnam/1203/2004 (Clade 1) vaccine or unprimed (received placebo) in previous vaccine studies were randomized to receive one (primed) or two (unprimed) 15- or 90-mcg doses of inactivated, A/H5N1/Indonesia/05/05 (Clade 2) vaccine. Peripheral blood mononuclear cells (PBMCs) were collected and analyzed from a subset of vaccinees to assess CMI responses using IFN-γ and granzyme B ELISPOT assays. Cytokine measurements were performed on PBMC supernatants after stimulation with H5N1 virus. RESULTS: PBMCs were available from 177 participants; 88 and 89 received 15-mcg and 90-mcg of unadjuvanted clade 2 vaccine, respectively. Following H5N1 clade 1 stimulation, IFN-γ but not granzyme B normalized spot-forming cell numbers had statistically significant increased numbers at each of the post-vaccination timepoints compared to baseline in pooled analyses of all vaccine doses and age groups. Clade 2 stimulation resulted in statistically significant increased numbers of IFN-γ cells only 180 days following the last vaccination. Responses were similar among younger and older study participants, as were responses among those primed with alum-adjuvanted or non-adjuvanted clade 1 H5N1 vaccines. The dosage of clade 2 vaccine did not impact CMI responses among primed subjects, but responses were statistically significantly greater in unprimed recipients of the 90-mcg dosage compared to unprimed recipients of the 15-mcg dosage. IFN-γ levels in the supernatants of stimulated PBMC were strongly correlated with IFN-γ ELISPOT results. CONCLUSION: CMI responses occur in adults administered influenza A/H5N1 inactivated influenza vaccine.

Association between microbial characteristics and poor outcomes among patients with methicillin-resistant Staphylococcus aureus pneumonia: a retrospective cohort study.

BACKGROUND: Methicillin-resistant S. aureus (MRSA) pneumonia is associated with poor clinical outcomes. This study examined the association between microbial characteristics and poor outcomes among patients with methicillin-resistant Staphylococcus aureus pneumonia. FINDINGS: This retrospective cohort study included 75 patients with MRSA pneumonia who were admitted to two large tertiary care medical centers during 2003-2010. Multivariable models were created using Cox proportional hazards regression and ordinal logistic regression to identify predictors of mortality or increased length of stay (LOS). None of the microbial characteristics (PFGE type, agr dysfunction, SCCmec type, and detection of PVL, ACME, and TSST-1) were significantly associated with 30-day mortality or post-infection hospital length of stay, after adjusting for gender, age, previous hospital admission within 12 months, previous MRSA infection or colonization, positive influenza test, Charlson Comorbidity Index score, and treatment (linezolid or vancomycin). CONCLUSION: Large prospective studies are needed to examine the impact of microbial characteristics on the risk of death and other adverse outcomes among patients with MRSA pneumonia.