WHO preferred product characteristics for monoclonal antibodies for passive immunization against respiratory syncytial virus (RSV) disease in infants - Key considerations for global use

World Health Organization (WHO) preferred product characteristics describe preferences for product attributes that would help optimize value and use to address global public health needs, with a particular focus on low- and middle-income countries. Having previously published preferred product characteristics for both maternal and paediatric respiratory syncytial virus (RSV) vaccines, WHO recently published preferred product characteristics for monoclonal antibodies to prevent severe RSV disease in infants. This article summarizes the key attributes from the preferred product characteristics and discusses key considerations for future access and use of preventive RSV monoclonal antibodies.

Immunogenicity and Safety of AS03-adjuvanted H5N1 Influenza Vaccine in Children 6-35 Months of Age: Results From a Phase 2, Randomized, Observer-blind, Multicenter, Dose-ranging Study

BACKGROUND

This phase 2 observer-blind, randomized, multicenter, dose-ranging study evaluated immunogenicity and safety of different formulations of an AS03-adjuvanted H5N1 influenza vaccine in children 6-35 months of age.

METHODS

One hundred eighty-five children randomized into 5 groups [1.9 µg hemagglutinin (HA)/AS03B, 0.9 µg HA/AS03C, 1.9 µg HA/AS03C, 3.75 µg HA/AS03C or 3.75 µg HA/AS03D] were to receive 2 doses administered 21 days apart (primary vaccination). AS03 was classified by amount of DL-α-tocopherol, with AS03B the highest amount. One year later, all subjects were to receive unadjuvanted 3.75 µg HA as antigen challenge. Immunogenicity was assessed 21 days after primary vaccination (day 42) and 7 days after antigen challenge (day 392). Immunogenicity-fever index, based on hemagglutination inhibition and microneutralization antibody titers at day 42 and fever 7 days after each vaccination, was used to guide the selection of an acceptable formulation.

RESULTS

After primary vaccination, formulations elicited strong homologous immune responses with all subjects' hemagglutination inhibition titers ≥1:40 post-vaccination. Immunogenicity-fever index based on hemagglutination inhibition and microneutralization assays showed that 1.9 µg HA/AS03B ranked the highest. Antibody levels persisted >4 times above baseline 12 months after primary vaccination with all formulations (day 385). Antibodies increased >4-fold after antigen challenge (day 392/day 385) with 1.9 µg HA/AS03B, 0.9 µg HA/AS03C and 1.9 µg HA/AS03C formulations. Overall per subject, the incidence of fever ranged from 28.6% (3.75 µg HA/AS03D) to 60.5% (1.9 µg HA/AS03B).

CONCLUSIONS

All formulations were highly immunogenic and demonstrated acceptable safety profiles, with the 1.9 µg HA/AS03B providing the most favorable balance of immunogenicity versus reactogenicity for use in children 6-35 months of age.

2319. Clinical Predictors of Influenza and Hospitalization of Children with Influenza in an Emergent Care Setting

Background

Objective measures utilizing early vital sign data show promise in predicting more severe outcomes among adults with influenza, but data are sparse in children. The objectives of this study were to determine the value of vital signs in predicting influenza infection or hospitalization due to influenza infection among children evaluated in an emergency department (ED) or urgent care (UC) setting in Colorado.

Methods

We evaluated vital signs obtained from a prospective cohort study of children aged 6 months to 8 years of age with influenza like illness evaluated at an ED/UC site in Aurora, CO from 2016–2018, and who underwent influenza testing by PCR. We collected the first set of vital signs, peak heart rate and temperature, and converted heart rate (HR) and respiratory rate (RR) to z-scores by age. HR z scores were further adjusted for temperature. Bivariable analyses for each vital sign as a predictor of influenza-related hospitalization and influenza infection as main outcomes were conducted. Predictors with P < 0.2 were entered into a multivariable logistic regression model to determine odds ratios (OR) and 95% CI; model performance was assessed using the Brier score and discriminative ability with the C statistic.

Results

Among 1478 children, 411 were positive for influenza, of which 28 were hospitalized. In multivariable analyses, among children with influenza infection, lower initial oxygen saturation (OR 0.87, 95% CI 0.78–0.98, P = 0.026) and higher adjusted respiratory rate (OR 2.09, 95% CI 1.21–3.61, P = 0.0085) were significant predictors of hospitalization (Figure 1). Among children with ILI, higher peak temperature (OR 1.46, 95% CI 1.30–1.63, P < 0.0001), lower adjusted peak heart rate (OR 0.79, 95% CI 0.69–0.90, P = 0.0005), higher initial oxygen saturation (OR 1.07, 95% CI 1.03–1.12 P = 0.002) and lower adjusted respiratory rate (OR 0.74, 95% CI 0.64–0.87, P = 0.0002) were significant predictors for having PCR-confirmed influenza. However, this model had poor calibration and discriminatory ability.

Conclusion

Higher respiratory rate adjusted for age and lower initial oxygen saturation were significant predictors of hospitalization among young children with PCR-confirmed influenza, but were not reliable discriminators of having influenza infection.

Disclosures

All authors: No reported disclosures.

986. Evaluation of Moderate-to-Severe Influenza Disease in Children 6 Months to 8 Years of Age in Colorado

Background

A clinical endpoint of moderate-to-severe (M/S) influenza has been proposed in children, defined as fever >39°C, otitis media, lower respiratory tract infection, or serious extrapulmonary manifestations. This definition has not been evaluated against clinically relevant outcomes like hospitalization, emergency room care, antimicrobial use, and child/parental absenteeism.

Methods

We conducted a prospective observational study of children aged 6 months–8 years with influenza at the Children’s Hospital Colorado Emergency Department (ED) and its affiliates during two influenza seasons (2016–2017 and 2017–2018). Children with influenza-like-illness (ILI) were enrolled and tested for influenza by polymerase chain reaction (PCR). Parents of influenza cases and matched influenza-negative controls were contacted 2 weeks later for follow-up. The primary outcome was hospitalization for M/S influenza vs. mild influenza. Secondary outcomes included recurrent ED visits, antimicrobial use, child/parental absenteeism. Interim analyses were conducted using SAS v9.4.

Results

Among the 1,480 enrolled children with ILI, 410 (28%) tested positive for influenza by PCR. The median age of influenza cases was 4.0 years (IQR 2.2–6.1), and 20% were considered high-risk for influenza complications. Of influenza cases, 284 (69%) met the definition for M/S influenza. Among M/S influenza subjects, 8.4% were hospitalized, compared with 1.6% with mild influenza (risk difference (RD) 6.9%; 95% CI: 3.0–10.8, P < 0.01). Subjects with M/S influenza were more likely to receive antibiotics (RD 12.0%, 95% CI: 3.4–20.6, P < 0.01) with a trend to higher antiviral use (RD 6.9%, 95% CI: −0.7–14.5, P = 0.09). There was no significant difference for recurrent ED visits nor child/parental absenteeism. After adjusting for comorbidities, age, and influenza strain, the relative risk (RR) of hospitalization or recurrent ED visits was higher among those with M/S influenza vs. mild influenza (RR 2.18, 95% CI: 1.02–4.64, P = 0.04).

Conclusion

Children with M/S influenza have a higher risk of hospitalization compared with mild disease. This proposed definition is a useful clinical endpoint to study the public health and clinical impact of influenza interventions in children.

Disclosures

S. Rao, GSK: Investigator, Research grant. E. Yanni, GSK: Employee, Salary. R. Bekkat-Berkani, GSK: Employee, Salary. A. Schuind, GSK: Employee, Salary. B. Innis, GSK: Employee, Salary. R. Mistry, GSK: Investigator, Research support. E. J. Asturias, GSK: Investigator, Research grant and Research support.

One or two doses of live varicella virus-containing vaccines: Efficacy, persistence of immune responses, and safety six years after administration in healthy children during their second year of life

BACKGROUND

This phase III B follow-up of an initial multicenter study (NCT00226499) will evaluate the ten-year efficacy of two doses of the combined measles-mumps-rubella-varicella vaccine (MMRV) and one dose of the live attenuated varicella vaccine (V) versus a measles-mumps-rubella control group (MMR) for the prevention of clinical varicella disease. Here we present efficacy results for six years post-vaccination.

METHODS

In phase A of the study, healthy children aged 12-22 months from ten European countries were randomized (3:3:1) and received either two doses of MMRV, or one dose of combined MMR and one dose of monovalent varicella vaccine (MMR+V), or two doses of the MMR vaccine (control), 42 days apart. Vaccine efficacy against all and against moderate or severe varicella (confirmed by detection of viral DNA or epidemiological link) was assessed from six weeks up to six years post-dose 2 for the MMRV and MMR+V groups, and was calculated with 95% confidence intervals (CI). The severity of varicella was calculated using the modified Vázquez scale (mild ≤ 7; moderately severe = 8-15; severe ≥ 16). Herpes zoster cases were also recorded.

RESULTS

5289 children (MMRV = 2279, mean age = 14.2, standard deviation [SD] = 2.5; MMR+V = 2266, mean age = 14.2, SD = 2.4; MMR = 744, mean age = 14.2, SD = 2.5 months) were included in the efficacy cohort. 815 varicella cases were confirmed. Efficacy of two doses of MMRV against all and against moderate or severe varicella was 95.0% (95% CI: 93.6-96.2) and 99.0% (95% CI: 97.7-99.6), respectively. Efficacy of one dose of varicella vaccine against all and against moderate or severe varicella was 67.0% (95% CI: 61.8-71.4) and 90.3% (95% CI: 86.9-92.8), respectively. There were four confirmed herpes zoster cases (MMR+V = 2, MMR = 2), all were mild and three tested positive for the wild-type virus.

CONCLUSIONS

Two doses of the MMRV vaccine and one dose of the varicella vaccine remain efficacious through six years post-vaccination.

Seeking help: B cells adapting to flu variability

The study of influenza vaccines has revealed potential interactions between preexisting immunological memory and antigenic context and/or adjuvantation. In the face of antigenic diversity, the process of generating B cell adaptability is driven by cross-reactive CD4 memory cells, such as T follicular helper cells from previous infections or vaccinations. Although such "helped" B cells are capable of adapting to variant antigens, lack of CD4 help could lead to a suboptimal antibody response. Collectively, this indicates an interplay between CD4 T cells, adjuvant, and B cell adaptability.

Comment on "CD4+ T cell autoimmunity to hypocretin/orexin and cross-reactivity to a 2009 H1N1 influenza A epitope in narcolepsy"

Scientists from the maker of the Pandemrix vaccine for influenza present their views on results linking epitopes in influenza and narcolepsy.

A randomized controlled study to evaluate the immunogenicity of a trivalent inactivated seasonal influenza vaccine at two dosages in children 6 to 35 months of age

The trivalent inactivated influenza vaccine Fluarix™ is licensed in the US for adults and children from 3 years old. This randomized observer-blind study (NCT00764790) evaluated Fluarix™ at two doses; 0.25 ml (Flu-25) and 0.5 ml (Flu-50) in children aged 6-35 months. The primary objective was to demonstrate immunogenic non-inferiority vs. a control vaccine (Fluzone®; 0.25 ml). Children received Flu-25 (n = 1107), Flu-50 (n = 1106) or control vaccine (n = 1104) at Day 0 and for un-primed children, also on Day 28. Serum hemagglutination-inhibition titers were determined pre-vaccination and at Day 28 (primed) or Day 56 (un-primed). Non-inferiority was assessed by post-vaccination geometric mean titer (GMT) ratio, (upper 95% confidence interval [CI] ≤ 1.5) and difference in seroconversion rate (upper 95% CI ≤ 10%). Reactogenicity/safety was monitored. The immune response to Flu-50 met all regulatory criteria. Indicated by adjusted GMT ratios [with 95% CI], the criteria for non-inferiority of Flu-50 vs. control vaccine were reached for the B/Florida strain (1.13 [1.01-1.25]) but not for the A/Brisbane/H1N1 (1.74 [1.54-1.98]) or A/Uruguay/H3N2 (1.72 [1.57-1.89]) strains. In children aged 18-35 months similar immune responses were observed for Flu-50 and the control vaccine. Flu-50 induced a higher response than Flu-25 for all strains. Temperature (≥ 37.5°C) was reported in 6.2%, 6.4%, and 6.6% of the Flu-25, Flu-50, and control group, respectively. Reactogenicity/safety endpoints were within the same range for all vaccines. In children aged 6-35 months, immune responses with Flu-50 fulfilled regulatory criteria but did not meet the pre-defined criteria for non-inferiority vs. control. This appeared to be due to differences in immunogenicity in children aged<18 months.

Safety and cross-reactive immunogenicity of candidate AS03-adjuvanted prepandemic H5N1 influenza vaccines: a randomized controlled phase 1/2 trial in adults

BACKGROUND

The tocopherol-based oil-in-water emulsion adjuvant system family (AS03) improves antigen sparing with split-virion H5N1 influenza vaccines, representing an important development for pandemic preparedness. In this phase 1/2 randomized, controlled, observer-blinded study in 680 adults, we assessed the immunogenicity and safety of A/Indonesia/5/05 H5N1 (IBCDC-RG2, clade 2.1) prepandemic candidate vaccines produced at 2 separate manufacturing sites.

METHODS

Two doses, each of which contained 3.75 microg of hemagglutinin antigen, were given 21 days apart either without adjuvant or with an adjuvant system containing 11.86 mg or 5.93 mg of tocopherol (AS03).

RESULTS

The AS03-adjuvanted A/Indonesia/05/2005 (NIBRG-14) vaccines were significantly more immunogenic than nonadjuvanted vaccine in homologous assays. Neutralizing cross-clade immunogenicity against clades 1, 2.2, and 2.3 was demonstrated at day 42 with all vaccines; at 6 months, seroconversion rates were highest for clade 2.2 (60.7%) and for clade 1 (38.3%). Adjuvantation was associated with increased short-term injection-site reactions (pain) in 80% of participants, with such reactions assessed as being of grade 3 severity for 4.0% of doses. No other safety or reactogenicity concerns were identified over 6 months of follow-up.

CONCLUSIONS

Humoral responses against the adjuvanted 3.75-microg hemagglutinin antigen vaccines from both manufacturing sites fulfilled European and US licensure criteria for immunogenicity for influenza vaccines.

Challenge of conducting a placebo-controlled randomized efficacy study for influenza vaccine in a season with low attack rate and a mismatched vaccine B strain: a concrete example

Background

Our aim was to determine the efficacy of a trivalent inactivated split virus influenza vaccine (TIV) against culture-confirmed influenza A and/or B in adults 18 to 64 years of age during the 2005/2006 season in the Czech Republic.

Methods

6203 subjects were randomized to receive TIV (N = 4137) or placebo (N = 2066). The sample size was based on an assumed attack rate of 4% which provided 90% power to reject the hypothesis that vaccine efficacy (VE) was ≥ 45%. Cases of influenza like illness (defined as fever (oral temperature ≥37.8°C) plus cough and/or sore throat) were identified both by active (biweekly phone contact) and passive (self reporting) surveillance and nasal and throat swabs were collected from subjects for viral culture.

Results

TIV was well tolerated and induced a good immune response. The 2005/2006 influenza season was exceptionally mild in the study area, as it was throughout Europe, and only 46 culture-confirmed cases were found in the study cohort (10 influenza A and 36 influenza B). Furthermore among the B isolates, 35 were identified as B/Hong Kong 330/2001-like (B/Victoria/2/87 lineage) which is antigenically unrelated to the vaccine B strain (B/Yamagata/16/88 lineage). The attack rate in the vaccine group (0.7%) was not statistically significantly different from the attack rate in the placebo group (0.9%).

Conclusion

Due to the atypical nature of the influenza season during this study we were unable to assess TIV efficacy. This experience illustrates the challenge of conducting a prospective influenza vaccine efficacy trial during a single season when influenza attack rates and drift in circulating strains or B virus lineage match can be difficult to estimate in advance.

Trial Registration

Clinical trial registery: NCT00197223.

Suspected transmission of methicillin-resistant Staphylococcus aureus between domestic pets and humans in veterinary clinics and in the household

OBJECTIVE

To describe MRSA infection and colonization in household pets, and transmission of MRSA between animals and humans.

METHODS

MRSA infection and colonization in household pets and human contacts were evaluated during investigations initiated after identification of MRSA infection or colonization of a household pet in order to determine if there had been transmission between animals and humans. All MRSA isolates were screened for Panton-Valentine leukocidin (PVL) genes by use of polymerase chain reaction, and isolate relatedness was determined by use of pulsed-field gel electrophoresis (PFGE).

RESULTS

Investigations of six situations where MRSA was identified in one or more animals in a household or veterinary facility were performed. MRSA was isolated from 8 animals (5 dogs and 3 cats) with clinical infections, 1 cat that was in contact with 2 infected cats and 14/88 (16%) of household contacts or veterinary personnel. Both animal-to-human and human-to-animal transmission were suspected. An indistinguishable MRSA isolate was recovered from at least one human that was in contact with each animal case. All isolates were classified as Canadian epidemic MRSA-2, the predominant community-associated MRSA clone in humans in Canada. No isolates possessed genes encoding for the PVL.

CONCLUSIONS

Transmission of MRSA between humans and animals, in both directions, was suspected. MRSA appears to be an emerging veterinary and zoonotic pathogen.

A short report on highlights of world-wide development of RIX4414: A Latin American experience

An oral, human-derived monovalent (G1P1A) rotavirus vaccine, strain RIX4414, has been developed by GlaxoSmithKline, Rixensart, Belgium. The safety, immunogenicity and efficacy of this vaccine were evaluated in a randomized, double-blind, placebo-controlled, phase IIb trial conducted in Brazil, Mexico and Venezuela. Healthy infants were given two doses of vaccine (104.7, 105.2 or 105.8 ffu) or placebo at age 2 and 4 months, with routine DTPw-HBV and Hib vaccines. OPV was given separately, at least 2 weeks before or after administration of the study vaccine. A total of 2155 infants were enrolled, of whom 1618 received one of the three vaccine viral concentrations and 537 were given placebo. Analysis of efficacy included diarrheal episodes occurring from 2 weeks after second dose until one year of age. Efficacy rates against any rotavirus gastroenteritis, severe rotavirus gastroenteritis and hospitalizations for rotavirus disease were as high as 70% (46-84%; 95%CI), 86% (63-96%; 95%CI), and 93% (54-100%; 95%CI), respectively. For non-G1 (mainly G9) serotypes, RIX4414 vaccine conferred protection as high as 83% (40-97%; 95%CI) against severe gastroenteritis. A decrease was noted in the incidence of severe rotavirus-related gastroenteritis after first dose. It is demonstrated that two doses of RIX4414 are highly efficacious against severe rotavirus gastroenteritis and hospitalization, including disease caused by non-G1 strains, namely G9 serotypes.

Efficacy of a bivalent L1 virus-like particle vaccine in prevention of infection with human papillomavirus types 16 and 18 in young women: a randomised controlled trial

BACKGROUND

Vaccination against the most common oncogenic human papillomavirus (HPV) types, HPV-16 and HPV-18, could prevent development of up to 70% of cervical cancers worldwide. We did a randomised, double-blind, controlled trial to assess the efficacy, safety, and immunogenicity of a bivalent HPV-16/18 L1 virus-like particle vaccine for the prevention of incident and persistent infection with these two virus types, associated cervical cytological abnormalities, and precancerous lesions.

METHODS

We randomised 1113 women between 15-25 years of age to receive three doses of either the vaccine formulated with AS04 adjuvant or placebo on a 0 month, 1 month, and 6 month schedule in North America and Brazil. Women were assessed for HPV infection by cervical cytology and self-obtained cervicovaginal samples for up to 27 months, and for vaccine safety and immunogenicity.

FINDINGS

In the according-to-protocol analyses, vaccine efficacy was 91.6% (95% CI 64.5-98.0) against incident infection and 100% against persistent infection (47.0-100) with HPV-16/18. In the intention-to-treat analyses, vaccine efficacy was 95.1% (63.5-99.3) against persistent cervical infection with HPV-16/18 and 92.9% (70.0-98.3) against cytological abnormalities associated with HPV-16/18 infection. The vaccine was generally safe, well tolerated, and highly immunogenic.

INTERPRETATION

The bivalent HPV vaccine was efficacious in prevention of incident and persistent cervical infections with HPV-16 and HPV-18, and associated cytological abnormalities and lesions. Vaccination against such infections could substantially reduce incidence of cervical cancer.

Identification of a novel hepatitis E virus in Nigeria

Sporadic cases of acute hepatitis E among ten native Nigerian adults were reported in Port-Harcourt (Nigeria). Hepatitis E virus (HEV) was detected in serum and/or faecal samples of seven patients by RT-PCR of the open reading frame (ORF)-1 polymerase region and the 3'-end of ORF2. Restriction analysis widely used to distinguish genotypes I and III showed that all Nigerian strains have a pattern similar to the Mexican strain (NotI, nt 286; SmaI, nt 397; no KpnI restriction site) but displayed a BsmI restriction site at nt 213 as do most African HEV strains sequenced so far. Sequence analysis performed from internal ORF1 and ORF2 PCR products displayed strong homogeneity between the HEV isolates, determining a regional cluster. Phylogenetic analysis of nucleotide sequences revealed that these strains were more related to the Mexican prototype genotype III (87% homology in ORF1, 80% homology in ORF2) than to either the African strain genotype I (74% homology in ORF1, 77% homology in ORF2) or the USA strain genotype II (75% homology in ORF1, 77% homology in ORF2). Genetic divergence up to 15% in ORF2 with the Mexican genotype clearly defined a new subgenotype within genotype III. At the amino acid level, Nigerian strains showed more homology with genotype III (96%) than with genotype I (92%). This study clearly determined the co-existence of genotypes I and III in Africa. These Nigerian HEV strains belonging to genotype III, but sharing some properties with genotype I, could be one of the missing links between African and Latin American HEV and could help us to determine the phylogenetic evolution of HEV from the ancestral virus.

IgM capture ELISA for detection of IgM antibodies to dengue virus: comparison of 2 formats using hemagglutinins and cell culture derived antigens

The highly sensitive AFRIMS format IgM capture ELISA for the diagnosis of dengue virus infections requires the use of mouse brain derived hemagglutinins and consequently also the use of 20% acetone extracted normal human serum to eliminate high background. These reagents are not always easily available and we have thus compared the AFRIMS format with another published format which uses cell culture derived antigens (culture fluid, CF, format) in order to determine if it is reasonable to use cell culture derived antigens in situations where hemagglutinins and normal human serum are difficult to obtain. The study shows that using AFRIMS results as the reference point, the CF format described here has a sensitivity of 90% and a specificity of 96%.