Mean Hemagglutination Inhibition Titers Research Articles

Immunogenicity of a new inactivated vaccine against feline panleukopenia virus, calicivirus, and herpesvirus-1 for cats

Feline panleukopenia virus (FPV), feline calicivirus (FCV), and feline herpesvirus type-1 (FHV-1) are major infectious pathogens in cats. We evaluated the immunogenicity of a new vaccine containing inactivated FPV, two FCVs, and FHV-1 in animals. An FPV, two FCVs, and an FHV-1 isolate were continuously passaged 70, 50, 80, and 100 times in CRFK cells. FP70, FC50, FC80, and FH100 were propagated and used as vaccine antigens. Two inactivated feline virus vaccines, Rehydragel-adjuvanted vaccine (FRAV) and Cabopol-adjuvanted vaccine (FCAV) were prepared and inoculated into mice and guinea pigs. Humoral immune responses were measured using hemagglutination inhibition (HI) for FPV and virus-neutralizing antibody (VNA) for two FCVs and FHV-1 tests. Serial passages in CRFK cells resulted in increase in titers of FPV and two FCVs but not FHV-1 The FCAV induced higher mean HI and VNA titers than the FRAV in guinea pigs; therefore, the FCAV was selected. Cats inoculated with FCAV developed a mean HI titer of 259.9 against FPV, and VNA titers of 64, 256, and 3.2 against FCV17D03, FCV17D283, and FHV191071, respectively. Therefore, cats inoculated with the FCAV showed a considerable immune response after receiving a booster vaccination.

Efficacy and safety of a quadrivalent influenza vaccine in children aged 6–35 months: A global, multiseasonal, controlled, randomized Phase III study

BackgroundChildren are an important target group for influenza vaccination, but few studies have prospectively evaluated influenza vaccine efficacy (VE) in children under 3 years of age. This was a randomized Phase III trial to assess the efficacy, immunogenicity, and safety of an inactivated quadrivalent influenza vaccine (QIV) in young children (EudraCT: 2016–004904–74). MethodsInfluenza-naïve children aged 6–35 months were randomized during three influenza seasons to receive vaccination with QIV or a non-influenza control vaccine. One group of participants was revaccinated with QIV in the subsequent influenza season. The primary efficacy endpoint was the absolute VE of QIV against influenza caused by any circulating strain. Key secondary efficacy endpoints included the absolute VE of QIV against influenza due to antigenically matching strains and immunogenicity. Safety and reactogenicity were also evaluated. ResultsIn total, 1005 children received QIV and 995 received control vaccine. Influenza A/B infection due to any circulating influenza strain occurred less frequently in children who received QIV versus children receiving a control vaccine. The absolute VE of QIV against any circulating influenza strain was 54% (95% confidence interval [CI]: 37%, 66%). The absolute VE of QIV against antigenically matching influenza strains was 68% (95% CI: 45%, 81%). Mean hemagglutination inhibition titers for all influenza strains in the QIV group increased post-vaccination, whereas increases were minimal in the control vaccine group; results from virus neutralization and neuraminidase-inhibition assays were generally consistent with the hemagglutination inhibition assay findings. Approximately 12 months after primary vaccination with QIV, antibody titers remained higher than pre-vaccination titers for most strains. In participants who were revaccinated, QIV elicited strong antibody responses. The overall safety profile and reactogenicity of QIV was comparable with control vaccine. ConclusionPrimary vaccination with QIV was well tolerated and effective in protecting children aged 6–35 months against influenza.

Application of frozen and stored glutaraldehyde-fixed turkey red blood cells for hemagglutination and hemagglutination inhibition assays for the detection and identification of influenza viruses

IntroductionHemagglutination (HA) and hemagglutination inhibition (HI) assays are conventionally used for the detection and identification of influenza viruses, using red blood cells (RBCs) from mammalian and avian sources. However, there could be limitations for availability of fresh RBCs due to situations such as pandemics, public health emergencies, outbreaks in avian species, lack of animal facilities, animal ethics concerns; or resource-constrained laboratories, and laboratories which do not carry out HA and HI assays routinely. Turkey RBCs (tRBCs) are widely used for HA and HI assays of influenza viruses. The present study explored the possibility of the use of glutaraldehyde-fixed tRBCs, which could be stored at -80 ºC and readily used for HA and HI assays. Materials and methodsA total of nine subtypes of human and avian influenza viruses, A H1N1, H3N2, H4N6, H5N1, H6N1, H7N9, H9N2, H11N1 and type B, were used in the study. Turkey RBCs were fixed with glutaraldehyde. The HA and HI assays were performed three times by two different operators using fresh and glutaraldehyde fixed tRBCs. The significance of difference in HA and HI titers between fixed and fresh RBCs was compared using ‘t-test’. The performance of fixed RBCs was evaluated before and after storing at -80 ºC for three weeks. ResultsThere was no significant difference (p > 0.05) between mean HA and HI titers using fresh and glutaraldehyde-fixed turkey RBCs. In addition, the HA and HI titers using fixed tRBCs before and after storing at -80 ºC were equivalent, indicating suitability of the fixed and stored RBCs. ConclusionsThis is the first report of the use of fixed and stored tRBCs for HA and HI assays of influenza viruses, highlighting their applicability as a ready-to-use reagent for laboratory diagnosis of influenza.

The role of live chicken markets as a source of replication and dissemination of Newcastle disease virus in chickens, northwest Ethiopia

Newcastle disease (ND) is perceived to be the major constraint in village chickens of Ethiopia causing huge economic loss. Village chickens are mobile and pass through markets, and live chicken markets are a highly productive source of ND virus replication, maintenance, and spread. However, in northwest of Ethiopia, there is a dearth of information on the role of live chicken markets in the maintenance and spread of ND in the village chickens. Therefore, a total of 480 apparently healthy chickens in the 4 live chicken markets were sampled with the aim to detect and estimate ND virus infection. Tracheal and cloacal swabs were collected from each bird and processed for virus isolation in 9- to 11-day-old embryonated chicken eggs, and hemagglutination inhibition (HI) assay was performed on all sera samples. The overall infection rate of ND virus was reported to be 39.2% (95% CI: 34.8–43.5). Of all chickens, 34.6% (95% CI: 30.3–38.9) had mean HI titer ≥4 log2, which was considered as protective. The mean hemagglutination titer for the ND virus was reported to be 6.0 log2, and mean antibody titer was reported to be 6.2 log2, with no statistically significant variation among the markets (P > 0.05). Newcastle disease occurrence was detected in all seasons of the year in the live bird markets, with the highest prevalence (55.8%) during the prerainy dry season (April and May), showing evidence for climatic and socioeconomic aspects as a risk factor in the occurrence of ND in indigenous chicken. In vivo virulence tests, mean death time of the embryo, and the intracerebral pathogenicity index revealed the presence of all pathotypes of ND virus strains: velogenic, mesogenic, and lentogenic. Apparently, healthy appearing birds were reported to be reservoirs of velogenic ND virus strains that could initiate endemicity of ND cycles in the village setting. Hence, it is strongly recommended to implement appropriate prevention and control measures to mitigate the economic loss caused by the disease.

Needle-free delivery of influenza vaccine using the Med-Jet® H4 is efficient and elicits the same humoral and cellular responses as standard IM injection: A randomized trial

BackgroundNeedle-free vaccine delivery systems have many potential advantages including increased vaccine compliance and decreased risk of needlestick injuries and syringe reuse. The Med-Jet® H4 is a gas-powered, auto-disabling disposable syringe jet injector. The Med-Jet family of products are currently being used in dermatology, podiatry, pain management and veterinary practices. The objectives of this study were to assess patient attitudes, time-efficiency, safety and immunogenicity of the seasonal influenza vaccine delivered by Med-Jet compared to the traditional needle-and-syringe. MethodsA total of 80 patients were randomized 2:1:1 to receive a commercial trivalent vaccine by Med-Jet or needle injection from a single-dose or multi-dose vial. Patient attitudes were assessed pre-randomization and post-immunization. Safety data were collected for 21 days post-immunization. Efficiency of vaccine administration was measured through a time-and-motion study. Humoral and cellular responses were assessed on Days 0 and 21. ResultsOverall, the participants readily accepted Med-Jet vaccination despite greater frequency of transient local reactions (eg: redness, swelling) immediately following immunization. Vaccine administration took slightly longer with the Med-Jet, but this difference decreased over time. Geometric mean hemagglutination inhibition titers, seroconversion and seroprotection rates in the Med-Jet and needle groups were equivalent for all influenza strains in the vaccine. Microneutralization responses were also essentially identical. There were no significant differences between the groups in the frequency of functional CD4 + T cells, memory subset distribution or poly-functionality. ConclusionsThese data suggest that the Med-Jet is an acceptable means of delivering seasonal influenza vaccine. The system was attractive to subjects, rapidly learned by skilled vaccine nurses and elicited both humoral and cellular responses that were indistinguishable from those elicited with needle injection. While other studies have assessed the humoral response to jet injection of influenza vaccine, to our knowledge, this study is the first to assess the cellular aspect of this response. (ClinTrials.gov-NCT03150537).

Kinetics of antibody response to influenza vaccination in renal transplant recipients

Annual vaccination is routinely used in organ transplant recipients for immunization against seasonal influenza. However, detailed analysis of the kinetics of vaccine-induced immune responses in this population is lacking. In this study, we investigated the kinetics of vaccine strains-specific antibody responses to trivalent influenza vaccine in a group of renal transplant recipients and a control group. First, we found that the geometric mean hemagglutination inhibition titer against all 3 vaccine strains in the transplant cohort was significantly low when compared to control subjects. Next, whereas the control group sera showed significantly higher HA-specific IgG and isotype IgG1 antibodies at all four time points, a similar increase in the transplant group was delayed until day 28. Interestingly, within the transplant group, subjects receiving belatacept/MMF/prednisone-based regimen had significantly lower levels of total IgG and HA-specific IgG when compared to tacrolimus/MMF/prednisone-based regimen. Even though IgG-ASC response in both cohorts peaked at day 7 post-vaccination, the frequency of IgG-ASC was significantly low in the transplant group. Taken together, our studies show delayed kinetics and lower levels of influenza vaccine-specific antibody responses in renal transplant recipients and, more importantly, indicate the need to probe and improve current vaccination strategies in renal transplant recipients.

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.

Low population serum microneutralization antibody titer against the predominating influenza A(H3N2) N121K virus during the severe influenza summer peak of Hong Kong in 2017

The 2017 Hong Kong influenza A(H3N2) summer season was unexpectedly severe. However, antigenic characterization of the 2017 circulating A(H3N2) viruses using ferret antisera did not show significant antigenic drift. We analyzed the hemagglutinin amino acid sequences of A(H3N2) virus circulating in Hong Kong in 2017, and found that viruses with hemagglutinin N121K substitution, which was rare before 2017, emerged rapidly and dominated in 2017 (52.4% of A[H3N2] virus in 2017 contains N121K substitution). Microneutralization assay using archived human sera collected from mid-2017 showed that the geometric mean microneutralization titer was 3.6-fold lower against a 2017 cell culture-grown circulating A(H3N2)-N121K virus (3391/2017 virus) than that against the cell culture-grown 2016–2017 A(H3N2) seasonal influenza vaccine-like vaccine virus (4801/2014 virus) (13.4 vs 41.8, P < 0.0001). Significantly fewer serum specimens had a microneutralization titer of 40 or above against 3391/2017 virus than that against 4801/2014 virus (26.4% vs 60.0%, P < 0.0001). Conversely, the geometric mean hemagglutination inhibition titer was slightly higher against 3391/2017 virus than that against the 4801/2014 virus (96.9 vs 55.4, P < 0.0001). Moreover, 59.1% of specimens had a significantly lower microneutralization antibody titer (≥4-fold) against 3391/2017 virus than that against 4801/2014 virus, but none for hemagglutination titer (P < 0.0001). Similar results of microneutralization and hemagglutination titers were observed for day 21-post-vaccination sera. Hence, the 2017 A(H3N2) summer peak in Hong Kong was associated with a low-microneutralization titer against the circulating virus. Our results support the use of microneutralization assay with human serum in assessing population susceptibility and antigenic changes of A(H3N2) virus. Novel and available immunization approach, such as topical imiquimod followed by intradermal vaccination, to broaden the neutralizing antibody response of influenza vaccine should be considered.

Immunogenicity and safety of a trivalent inactivated influenza vaccine produced in Shenzhen, China

ABSTRACT A split-virion trivalent inactivated influenza vaccine produced according to the Chinese pharmacopeia (Shz-IIV3) has been commercially available in China since 2014. Here, we describe the results of a phase IV open-label trial to describe the immunogenicity and safety of the 2014–2015 Northern Hemisphere formulation of Shz-IIV3 in individuals ≥ 6 months of age. Subjects 6–35 months of age received 2 half-doses of Shz-IIV3 (0.25 ml) 28 d apart, and subjects ≥ 3 y of age received a single full dose (0.5 ml). The study included 602 subjects. Except for the A (H3N2) strain in subjects 3–17 years, geometric mean hemagglutination inhibition titer ratios were ≥ 10 and rates of seroconversion/significant increase in titer were ≥ 78% in all age groups. For the H3N2 strain in subjects 3–17 years, the geometric mean titer ratio was 3.8 and the rate of seroconversion/significant increase was 56%. Post-vaccination seroprotection rates were ≥ 88% for all strains in all age groups. The most common solicited reactions were injection-site pain/tenderness and fever, most of which were grade 1 and resolved within 3 d. Vaccine-related unsolicited adverse events were reported only by subjects 6–23 months, most of which were mild abnormal crying and irritability. No vaccine-related serious adverse events and no deaths were reported. No new safety signals or unexpected safety events occurred, although an immediate anaphylactic skin reaction occurred in one subject. This study confirmed that the 2014–2015 Northern Hemisphere formulation of Shz-IIV3 was well tolerated and highly immunogenic in subjects ≥ 6 months of age.

Safety and immunogenicity of an intramuscular quadrivalent influenza vaccine in children 3 to 8 y of age: A phase III randomized controlled study

ABSTRACTA quadrivalent, inactivated, split-virion influenza vaccine containing a strain from both B lineages (IIV4) has been developed, but its safety and immunogenicity in young children has not been described. This was a phase III, randomized, double-blind, active-controlled, multi-center study to examine the immunogenicity and safety of IIV4 in children 3–8 y of age (EudraCT no. 2011-005374-33). Participants were randomized 5:1:1 to receive the 2013/2014 Northern Hemisphere formulation of IIV4, an investigational trivalent comparator (IIV3) containing the B/Victoria lineage strain, or the licensed Northern Hemisphere IIV3 containing the B/Yamagata lineage strain. Participants who had not previously received a full influenza vaccination schedule received 2 doses of vaccine 28 d apart; all others received a single dose. 1242 children were included. For all 4 strains, IIV4 induced geometric mean haemagglutination inhibition titres non-inferior to those induced by the IIV3 comparators. For both B strains, geometric mean antibody titres induced by IIV4 were superior to those induced by the IIV3 with the alternative lineage strain. Similar proportions of participants vaccinated with IIV4 and IIV3 reported solicited injection-site reactions, solicited systemic reactions, and vaccine-related adverse events. A single vaccine-related serious adverse event, thrombocytopenia, was reported 9 d after vaccination with IIV4 and resolved without sequelae. In conclusion, in children aged 3–8 y who received one dose or 2 doses 28 d apart, IIV4 had an acceptable safety profile, was as immunogenic as IIV3 for the shared strains, and had superior immunogenicity for the additional B strain.

Safety and immunogenicity of high-dose trivalent inactivated influenza vaccine in adults 50–64 years of age

BackgroundIndividuals 50–64 years of age have reduced immune responses to influenza vaccines. The current study examined whether a high-dose inactivated trivalent influenza vaccine (IIV3-HD) might improve immune responses over a standard-dose inactivated influenza vaccine (IIV3-SD) in this age group. MethodsThis was a multicenter, observer-blinded, randomized, active-controlled phase II trial. Adults 50–64 years of age were randomized 1:1 to receive IIV3-HD or IIV3-SD. Hemagglutination inhibition titers were measured before and 28 days after vaccination. Reactogenicity was recorded for 7 days after vaccination and adverse events for 28 days. Results148 participants received IIV3-HD and 152 received IIV3-SD. For all vaccine strains, day 28 geometric mean hemagglutination inhibition titers were significantly higher in the IIV3-HD group than in the IIV3-SD group (geometric mean titer ratio [95% confidence interval (CI)]=1.43 [1.04–1.97] for A/H1N1, 1.65 [1.21–2.25] for A/H3N2, and 1.60 [1.23–2.08] for B). Seroconversion rates were significantly higher in the IIV3-HD group than in the IIV3-SD group for strains A/H3N2 and B but not A/H1N1 (difference [95% CI]=13.5% [4.76–22.0] for A/H3N2, 23.1% [11.7–33.6] for B, and −0.2% [−9.66 to 9.18] for A/H1N1). The post-vaccination seroprotection rate was significantly higher in the IIV3-HD group than in the IIV3-SD group for strain B but not for strains A/H1N1 or A/H3N2 (difference=9.1% [2.95–15.7] for B, 2.0% [−0.907 to 5.68] for A/H1N1, and 0.6% [−3.14 to 4.43] for A/H3N2). Reactogenicity was higher in the IIV3-HD group than in the IIV3-SD group, but reactions were mostly of low intensity, transient, and self-limited. Rates of unsolicited adverse events were similar between groups. No serious AEs, AEs leading to early withdrawal, or deaths were reported. ConclusionsThe study suggests that in adults 50–64 years of age, IIV3-HD may improve immunogenicity compared to IIV3-SD while maintaining an acceptable safety profile.

Enhanced and persistent antibody response against homologous and heterologous strains elicited by a MF59®-adjuvanted influenza vaccine in infants and young children

BackgroundNon-adjuvanted seasonal influenza vaccines show only modest efficacy in young children. This study compared the immunogenicity, reactogenicity and safety of the MF59®-adjuvanted trivalent subunit vaccine (aTIV) with two non-adjuvanted trivalent vaccines, TIV-1, the non-adjuvanted version of aTIV, and TIV-2, a split virion vaccine. Methods6078 children received two doses of aTIV (n=3125), TIV-1 (n=1479), or TIV-2 (n=1474) four weeks apart (Days 1 and 29). Children aged 6 to <36 months and 36 to <72 months received 0.25mL and 0.50mL doses, respectively. Immunogenicity was assessed by hemagglutination inhibition (HI) assay (n=2435) on Days 1, 29, 50 and 209. Safety was assessed up to Day 394. ResultsAfter the second vaccination (Day 50), the aTIV group showed significantly higher geometric mean HI titers and seroconversion rates than the TIV-1 or TIV-2 groups against all homologous and heterologous strains. The difference was enhanced at HI titers ≥110. aTIV elicited a faster, more persistent antibody response, with significantly higher titers in the aTIV group after one vaccination (Day 29) and after six months (Day 209) than in either TIV group. aTIV was more reactogenic than were TIV-1 and TIV-2 but rates of severe adverse events were very low for all three vaccines. ConclusionIn infants and young children, the MF59-adjuvanted vaccine induced substantially faster (after one dose), higher, persistent HI titers than the non-adjuvanted vaccines, with consistently higher seroprotection rates at increased threshold HI titers.This trial is registered at clinicaltrials.gov: NCT01346592.

Nine μg intradermal influenza vaccine and 15 μg intramuscular influenza vaccine induce similar cellular and humoral immune responses in adults

Intanza® 9 μg (Sanofi Pasteur), a trivalent split-virion vaccine administered by intradermal (ID) injection, was approved in Europe in 2009 for the prevention of seasonal influenza in adults 18 to 59 years. Here, we examined the immune responses induced in adults by the ID 9 μg vaccine and the standard trivalent intramuscular (IM) vaccine (Vaxigrip® 15 μg, Sanofi Pasteur). This trial was a randomized, controlled, single-center, open-label study in healthy adults 18 to 40 years of age during the 2007/8 influenza season. Subjects received a single vaccination with the ID 9 μg (n = 38) or IM 15 μg (n = 42) vaccine. Serum, saliva, and peripheral blood mononuclear cells were collected up to 180 days post-vaccination.Geometric mean hemagglutination inhibition titers, seroprotection rates, seroconversion rates, and pre-vaccination-to-post-vaccination ratios of geometric mean hemagglutination inhibition titers did not differ between the two vaccines. Compared with pre-vaccination, the vaccines induced similar increases in vaccine-specific circulating B cells at day 7 but did not induce significant increases in vaccine-specific memory B cells at day 180. Cell-mediated immunity to all three vaccine strains, measured in peripheral blood mononuclear cells, was high at baseline and not increased by either vaccine. Neither vaccine induced a mucosal immune response. These results show that the humoral and cellular immune responses to the ID 9 μg vaccine are similar to those to the standard IM 15 μg vaccine.

Seroprevalence Survey of Avian influenza A (H5) in wild migratory birds in Yunnan Province, Southwestern China

BackgroundHighly pathogenic avian influenza virus (HPAIV) is a highly contagious disease which is a zoonotic pathogen of significant economic and public health concern. The outbreaks caused by HPAIV H5N1 of Asian origin have caused animal and human disease and mortality in several countries of Southeast Asia, such as Bangladesh, Cambodia, China, India, Indonesia, Laos, Myanmar, Thailand and Viet Nam. For the first time since 1961, this HPAIV has also caused extensive mortality in wild birds and has sparked debate of the role wild birds have played in the spread of this virus. Other than confirmed mortality events, little is known of this virus in wild birds. There is no report on the seroprevalence of avian influenza H5 infection in wild migratory birds in Yunnan Province. In this study we examined live wild birds in Yunnan Province for H5 specific antibody to better understand the occurrence of this disease in free living birds.MethodsSera from 440 wild birds were collected from in Kunming and Northern Ailaoshan of Yunnan Province, Southwestern China, and assayed for H5 antibodies using the hemagglutination inhibition (HI) assays.ResultsThe investigation revealed that the seroprevalence of avian influenza H5 was as following: Ciconiiformes 2.6%, Strigiformes 13.04%, Passeriformes 20%, Cuculiformes 21.74%, Gruiformes 0%, Columbiformes 0%, Charadriiformes 0% and Coraciiformes 0%. Statistical analyses showed that there was a significant difference of prevalence between the orders (P < 0.01). Specific avian influenza H5 antibodies were detected in 23 of 440 (5.23%) sera. Mean HI titer 23 positive sera against H5 were 5.4 log2.ConclusionsThe results of the present survey indicated that the proportion of wild birds had previously infected AIV H5 at other times of the year. To our knowledge, this is the first seroprevalence report of avian influenza H5 infection in wild migratory birds in China’ s southwestern Yunnan Province. The results of the present survey have significant public health concerns.

Effects of black cumin seed (Nigella sativa L.) on performance and immune system in newly evolved crossbred laying hens

Background: A limited number of studies have tested the effect of diets supplemented with black cumin seed (BCS) on the performance of laying hen. Objective: To determine the effects of various levels of dietary BCS on the performance of laying hen. Birds and methods: Three hundred 40-week-old rural Leghorn (White Leghorn males X F1 females of Fayoumi male X Rhode Island Red female) crossbred hens were randomly assigned to four groups with five replicates of 15 birds each (75 laying hens per group), and fed diets supplemented with 0%, 3%, 4% or 5% BCS for 60 days. Statistical analysis was performed by means of ANOVA. Results: BCS at all levels revealed greater egg production, egg weight and egg mass than the control group. Similarly, feed conversion was improved by 0.50, 0.55 and 0.36 points compared to controls with the addition of 3%, 4% or 5% levels of BCS, respectively. Haugh units and yolk weights of eggs from hens that were fed diets containing 3%, 4% and 5% BCS were significantly greater than those from the control group. Supplementation of 4% or 5% BCS significantly increased shell thickness and decreased serum LDL cholesterol and egg yolk cholesterol concentration as compared to other groups. Mean hemagglutination inhibition titers against Newcastle disease virus were higher than in controls. Conclusion: BCS at levels of 4% or 5% positively influenced egg production, egg weight and shell quality. Furthermore, it decreased the concentration of serum LDL cholesterol and egg yolk cholesterol concentrations and enhanced immunity against Newcastle disease virus.

Immunogenicity and safety of inactivated influenza vaccines in primed populations: A systematic literature review and meta-analysis

Several inactivated influenza vaccine formulations for systemic administration in man are currently available for annual (seasonal) immunization: split virus and subunit (either plain-aqueous, or virosomal, or adjuvanted by MF59). From a literature search covering the period 1978–2009, 33 articles could be identified, which described randomized clinical trials comparing at least two of the four vaccine formulations with respect to serum hemagglutination inhibition (HI) antibody response, local and systemic vaccine reactions and serious adverse events after vaccination, and employing seasonal vaccine components and doses. In total, 9121 vaccinees of all ages, either healthy or with underlying diseases, were involved. Most vaccinees were primed or had been vaccinated in previous years. For immunogenicity, homologous post-vaccination geometric mean HI titers (GMTs) were analyzed by a random effects model for continuous data. Unreported standard deviations (SD) were addressed by imputing assumed SD-values. Age and health state of the vaccinees appeared to have little influence on the outcome. The immunogenicity of split, aqueous and virosomal subunit formulations were similar, with geometric mean ratio values (GMR, quotient of paired GMT-values) varying around one (0.93–1.24). The MF59-adjuvanted subunit vaccine induced, on average, larger antibody titers than the non-adjuvanted vaccine formulations, but the absolute increase was small (GMR-values varying between 1.25 and 1.40). Vaccine reactions were analyzed using a random effects model for binary data. Local and systemic reactogenicity was similar among non-adjuvanted formulations. The adjuvanted subunit formulation was more frequently associated with local reactions than the non-adjuvanted formulations (rate ratio: 2.12, significant). Systemic reactions were similar among all vaccine formulations. The original articles emphasized the mild and transient character of the vaccine reactions and the absence of serious vaccine-related adverse events. This adequate amount of evidence led to the conclusion that all the currently available inactivated influenza vaccine formulations are safe, well tolerated and similarly effective to control seasonal influenza outbreaks across primed populations and age ranges.

Effect on Cellular and Humoral Immune Responses of the AS03 Adjuvant System in an A/H1N1/2009 Influenza Virus Vaccine Administered to Adults during Two Randomized Controlled Trials

The influence of AS03(A), a tocopherol oil-in-water emulsion-based adjuvant system, on humoral and cell-mediated responses to A/California/7/2009 H1N1 pandemic vaccine was investigated. In two observer-blind studies, a total of 261 healthy adults aged 18 to 60 years were randomized to receive either AS03(A)-adjuvanted H1N1 vaccine containing 3.75 μg hemagglutinin (HA) or nonadjuvanted H1N1 vaccine containing 15 or 3.75 μg HA on days 0 and 21. Hemagglutination inhibition (HI) antibody and T-cell responses were analyzed up to day 42. A first dose of AS03(A)-adjuvanted vaccine (3.75 μg HA) or nonadjuvanted vaccine (15 μg HA) induced HI responses of similar magnitudes that exceeded licensure criteria (e.g., 94 to 100% with titers of ≥ 40). A lower response following 3.75 μg HA without adjuvant was observed (73% with titers of ≥ 40). Following a second dose, geometric mean HI titers at day 42 were higher for AS03(A)-adjuvanted vaccine (636 and 637) relative to nonadjuvanted vaccine (341 for 15 μg HA and 150 for 3.75 μg HA). Over the 42-day period, the increase in frequency of A/H1N1/2009-specific CD4⁺ T cells was significantly higher in the adjuvanted group than in the nonadjuvanted group. There was no evidence of correlation between baseline CD4⁺ T-cell frequencies and day 21 HI antibody titers, while there was some correlation (R = 0.35) between day 21 CD4⁺ T-cell frequencies and day 42 HI titers. AS03(A) adjuvant enhanced the humoral and CD4⁺ T-cell-mediated responses to A/H1N1/2009 vaccine. Baseline A/H1N1/2009-specific CD4⁺ T-cell frequencies did not predict post-dose 1 antibody responses, but there was some correlation between post-dose 1 CD4⁺ T-cell frequencies and post-dose 2 antibody responses.

The Effect of Storage Conditions on the Potency of Newcastle Disease Vaccine La Sota

Thirty (30) vials of Newcastle Disease (ND) vaccine. La Sota were procured locally and tested for potency when stored under conditions of irregular power supply. The vaccines were of the same batch and were eighteen months to the expiration time. The potency of the vaccines was tested using Haemagglutination (HA) test before storage. The vaccines’ immunogenicity was determined in a batch of 250, 3 weeks old white cockerels after which the vaccines were stored in the refrigerator with two-third of the storage period at 0-4 C and the remaining one third at room temperature of 26-30 C. During the study, the o o methods of vaccine storage were alternated frequently to reflect the frequent power outages. The humoral immune response of the vaccinated chickens was estimated by Haemagglutination Inhibition (HI) test. The potency of the vaccines was tested on days 28, 56, 84, 112 and 140 post storage. On day 140, another batch of 250, 3 weeks old white cockerels were vaccinated with a vial from the stock and the humoral immune response of these chickens was evaluated at 3 weeks post vaccination. The mean HA titre of the vaccine before storage was 128, while the mean HA titres of the vaccines after storage (i.e., day 140) was 8. The mean HI titres of the vaccinated chickens before and after storage were 1005.7 and 8.3, respectively. Student t test was used to compare the mean HI titre of the chicken vaccinated prior and at the end of vaccine storage. The GMT mean HI titre of the chickens vaccinated prior to storage was significantly (p<0.05) higher than that of the chicken vaccinated at the end of vaccine storage.

Randomized, Double‐Blind Controlled Phase 3 Trial Comparing the Immunogenicity of High‐Dose and Standard‐Dose Influenza Vaccine in Adults 65 Years of Age and Older

Influenza-associated morbidity and mortality has not decreased in the last decade, despite increased receipt of vaccine. To improve the immunogenicity of influenza vaccine, a high-dose (HD) trivalent, inactivated influenza vaccine was developed. A multicenter, randomized, double-blind controlled study was conducted to compare HD vaccine (which contains 60 microg of hemagglutinin per strain) with the licensed standard-dose (SD) vaccine (which contains 15 microg of hemagglutinin per strain) in adults > or = 65 years of age. HD vaccine was administered to 2575 subjects, and SD vaccine was administered to 1262 subjects. There was a statistically significant increase in the rates of seroconversion and mean hemagglutination inhibition titers at day 28 after vaccination among those who received HD vaccine, compared with those who received SD vaccine. Mean postvaccination titers for individuals who received HD vaccine were 116 for H1N1, 609 for H3N2, and 69 for B strain; for those who received SD vaccine, mean postvaccination titers were as 67 for H1N1, 333 for H3N2, and 52 for B strain. The HD vaccine met superiority criteria for both A strains, and the responses for B strain met non-inferiority criteria. Seroprotection rates were also higher for those who received HD vaccine than for those who received SD vaccine vaccine, for all strains. Local reactions were more frequent in individuals who received HD vaccine, but the reactions were mild to moderate. There was a statistically significant increase in the level of antibody response induced by HD influenza vaccine, compared with that induced by SD vaccine, without an attendant increase in the rate or severity of clinically relevant adverse reactions. These results suggest that the high-dose vaccine may provide improved protective benefits for older adults. ClinicalTrials.gov identifier: NCT00391053 .

Serological Responses of Chickens to Low Challenge Doses of Mycoplasma Synoviae

Groups of eight chickens were challenged with 10-fold dilutions of one of two strains of Mycoplasma synoviae (MS); each challenge group contained two noninfected sentinels. Both strains were highly efficient in colonizing the respiratory tract with challenge doses as low as 76 and 24 color-changing units/bird. Infection spread rapidly (within 7 days) to sentinels, while uninfected control chickens separated from infected chickens by two empty pens remained uninfected for the 56-day experimental period. Although sentinels and birds challenged with the lowest doses had weaker or slightly slower antibody responses in some cases as measured by serum plate agglutination, enzyme-linked immunosorbent assay (ELISA), and hemagglutination inhibition (HI), they generally exhibited a typical antibody response. Agglutination reactions tended to be weak, but a high percentage of tests (generally >30% from day 14 postchallenge) were positive. ELISA results were variable, and in some cases reactor rates were low (generally <20%), even though the chickens were colonized in the upper respiratory tract. The HI test was reliable in detecting infected groups; usually >50% were positive from 14 days postchallenge. Mean HI titers were higher when using hemagglutination antigens prepared from the homologous MS strain as compared with antigen prepared from the heterologous strain or with standard antigen prepared from WVU 1853.