Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants.

BACKGROUND: Whether vaccination during pregnancy could reduce the burden of respiratory syncytial virus (RSV)-associated lower respiratory tract illness in newborns and infants is uncertain. METHODS: In this phase 3, double-blind trial conducted in 18 countries, we randomly assigned, in a 1:1 ratio, pregnant women at 24 through 36 weeks' gestation to receive a single intramuscular injection of 120 µg of a bivalent RSV prefusion F protein-based (RSVpreF) vaccine or placebo. The two primary efficacy end points were medically attended severe RSV-associated lower respiratory tract illness and medically attended RSV-associated lower respiratory tract illness in infants within 90, 120, 150, and 180 days after birth. A lower boundary of the confidence interval for vaccine efficacy (99.5% confidence interval [CI] at 90 days; 97.58% CI at later intervals) greater than 20% was considered to meet the success criterion for vaccine efficacy with respect to the primary end points. RESULTS: At this prespecified interim analysis, the success criterion for vaccine efficacy was met with respect to one primary end point. Overall, 3682 maternal participants received vaccine and 3676 received placebo; 3570 and 3558 infants, respectively, were evaluated. Medically attended severe lower respiratory tract illness occurred within 90 days after birth in 6 infants of women in the vaccine group and 33 infants of women in the placebo group (vaccine efficacy, 81.8%; 99.5% CI, 40.6 to 96.3); 19 cases and 62 cases, respectively, occurred within 180 days after birth (vaccine efficacy, 69.4%; 97.58% CI, 44.3 to 84.1). Medically attended RSV-associated lower respiratory tract illness occurred within 90 days after birth in 24 infants of women in the vaccine group and 56 infants of women in the placebo group (vaccine efficacy, 57.1%; 99.5% CI, 14.7 to 79.8); these results did not meet the statistical success criterion. No safety signals were detected in maternal participants or in infants and toddlers up to 24 months of age. The incidences of adverse events reported within 1 month after injection or within 1 month after birth were similar in the vaccine group (13.8% of women and 37.1% of infants) and the placebo group (13.1% and 34.5%, respectively). CONCLUSIONS: RSVpreF vaccine administered during pregnancy was effective against medically attended severe RSV-associated lower respiratory tract illness in infants, and no safety concerns were identified. (Funded by Pfizer; MATISSE ClinicalTrials.gov number, NCT04424316.).

A Transient, Excited Species of the Autoinhibited α-State of the Bacterial Transcription Factor RfaH May Represent an Early Intermediate on the Fold-Switching Pathway.

RfaH is a two-domain transcription factor in which the C-terminal domain switches fold from an α-helical hairpin to a ß-roll upon binding the ops-paused RNA polymerase. To ascertain the presence of a sparsely populated excited state that may prime the autoinhibited resting state of RfaH for binding ops-paused RNA polymerase, we carried out a series of NMR-based exchange experiments to probe for conformational exchange on the millisecond time scale. Quantitative analysis of these data reveals exchange between major ground (∼95%) and sparsely populated excited (∼5%) states with an exchange lifetime of ∼3 ms involving residues at the interface between the N-terminal and C-terminal domains formed by the ß3/ß4 hairpin and helix α3 of the N-terminal domain and helices α4 and α5 of the C-terminal domain. The largest 15N backbone chemical shift differences are associated with the ß3/ß4 hairpin, leading us to suggest that the excited state may involve a rigid body lateral displacement/rotation away from the C-terminal domain to adopt a position similar to that seen in the active RNA polymerase-bound state. Such a rigid body reorientation would result in a reduction in the interface between the N- and C-terminal domains with the possible introduction of a cavity or cavities. This hypothesis is supported by the observation that the population of the excited species and the exchange rate of interconversion between ground and excited states are reduced at a high (2.5 kbar) pressure. Mechanistic implications for fold switching of the C-terminal domain in the context of RNA polymerase binding are discussed.

Efficacy of a 4-Antigen Staphylococcus aureus Vaccine in Spinal Surgery: The STaphylococcus aureus suRgical Inpatient Vaccine Efficacy (STRIVE) Randomized Clinical Trial.

BACKGROUND: Staphylococcus aureus is a global pathogen that is frequently responsible for healthcare-associated infections, including surgical site infections (SSIs). Current infection prevention and control approaches may be limited, with S. aureus antibiotic resistance remaining problematic. Thus, a vaccine to prevent or reduce S. aureus infection is critically needed. We evaluated the efficacy and safety of an investigational 4-antigen S. aureus vaccine (SA4Ag) in adults undergoing elective open posterior spinal fusion procedures with multilevel instrumentation. METHODS: In this multicenter, site-level, randomized, double-blind trial, patients aged 18-85 years received a single dose of SA4Ag or placebo 10-60 days before surgery. SA4Ag efficacy in preventing postoperative S. aureus bloodstream infection and/or deep incisional or organ/space SSIs was the primary end point. Safety evaluations included local reactions, systemic events, and adverse events (AEs). Immunogenicity and colonization were assessed. RESULTS: Study enrollment was halted when a prespecified interim efficacy analysis met predefined futility criteria. SA4Ag showed no efficacy (0.0%) in preventing postoperative S. aureus infection (14 cases in each group through postoperative day 90), despite inducing robust functional immune responses to each antigen compared with placebo. Colonization rates across groups were similar through postoperative day 180. Local reactions and systemic events were mostly mild or moderate in severity, with AEs reported at similar frequencies across groups. CONCLUSIONS: In patients undergoing elective spinal fusion surgical procedures, SA4Ag was safe and well tolerated but, despite eliciting substantial antibody responses that blocked key S. aureus virulence mechanisms, was not efficacious in preventing S. aureus infection. Clinical Trials Registration. NCT02388165.

Safety and Immunogenicity of Bivalent RSVpreF Vaccine Coadministered with Seasonal Inactivated Influenza Vaccine in Older Adults.

BACKGROUND: Respiratory syncytial virus (RSV) and influenza are both typically seasonal diseases, with winter peaks in temperate climates. Coadministration of an RSV vaccine and influenza vaccine could be a benefit, requiring 1 rather than 2 visits to a healthcare provider for individuals receiving both vaccines. METHODS: The primary immunogenicity objective of this phase 3, 1:1 randomized, double-blind, placebo-controlled study in healthy ≥65-year-olds in Australia was to demonstrate noninferiority of immune responses with coadministration of the stabilized RSV prefusion F protein-based vaccine (RSVpreF) and seasonal inactivated influenza vaccine (SIIV) versus SIIV or RSVpreF administered alone, using a 1.5-fold noninferiority margin (lower bound 95% CI >0.667). Safety and tolerability were evaluated by collecting reactogenicity and adverse event data. RESULTS: Of 1403 participants randomized, 1399 received vaccinations (median [range] age, 70 [65‒91] years). Local reactions and systemic events were mostly mild or moderate when RSVpreF was coadministered with SIIV or administered alone. No vaccine-related serious adverse events were reported. Geometric mean ratios were 0.86 for RSV-A and 0.85 for RSV-B neutralizing titers at 1 month after RSVpreF administration and 0.77 to 0.90 for strain-specific hemagglutination inhibition assay titers at 1 month after SIIV. All comparisons achieved the prespecified 1.5-fold noninferiority margin. CONCLUSION: The primary study objectives were met, demonstrating noninferiority of RSVpreF and SIIV immune responses when RSVpreF was coadministered with SIIV and that RSVpreF had an acceptable safety and tolerability profile when coadministered with SIIV. The results of this study support coadministration of RSVpreF and SIIV in an older adult population. CLINICAL TRIAL REGISTRATION: NCT05301322.

Experimental NOE, Chemical Shift, and Proline Isomerization Data Provide Detailed Insights into Amelotin Oligomerization.

Amelotin is an intrinsically disordered protein (IDP) rich in Pro residues and is involved in hydroxyapatite mineralization. It rapidly oligomerizes under physiological conditions of pH and pressure but reverts to its monomeric IDP state at elevated pressure. We identified a 105-residue segment of the protein that becomes ordered upon oligomerization, and we used pressure-jump NMR spectroscopy to measure long-range NOE contacts that exist exclusively in the oligomeric NMR-invisible state. The kinetics of oligomerization and dissociation were probed at the residue-specific level, revealing that the oligomerization process is initiated in the C-terminal half of the segment. Using pressure-jump NMR, the degree of order in the oligomer at the sites of Pro residues was probed by monitoring changes in cis/trans equilibria relative to the IDP state after long-term equilibration under oligomerizing conditions. Whereas most Pro residues revert to trans in the oligomeric state, Pro-49 favors a cis configuration and three Pro residues retain an unchanged cis fraction, pointing to their local lack of order in the oligomeric state. NOE contacts and secondary 13C chemical shifts in the oligomeric state indicate the presence of an 11-residue α-helix, preceded by a small intramolecular antiparallel ß-sheet, with slower formation of long-range intermolecular interactions to N-terminal residues. Although none of the models generated by AlphaFold2 for the amelotin monomer was consistent with experimental data, subunits of a hexamer generated by AlphaFold-Multimer satisfied intramolecular NOE and chemical shift data and may provide a starting point for developing atomic models for the oligomeric state.

A methyl-TROSY based 13C relaxation dispersion NMR experiment for studies of chemical exchange in proteins.

A methyl Transverse Relaxation Optimized Spectroscopy (methyl-TROSY) based, multiple quantum (MQ) 13C Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion NMR experiment is described. The experiment is derived from the previously developed MQ 13C-1H CPMG scheme (Korzhnev in J Am Chem Soc 126: 3964-73, 2004) supplemented with a CPMG train of refocusing 1H pulses applied with constant frequency and synchronized with the 13C CPMG pulse train. The optimal 1H 'decoupling' scheme that minimizes the amount of fast-relaxing methyl MQ magnetization present during CPMG intervals, makes use of an XY-4 phase cycling of the refocusing composite 1H pulses. For small-to-medium sized proteins, the MQ 13C CPMG experiment has the advantage over its single quantum (SQ) 13C counterpart of significantly reducing intrinsic, exchange-free relaxation rates of methyl coherences. For high molecular weight proteins, the MQ 13C CPMG experiment eliminates complications in the interpretation of MQ 13C-1H CPMG relaxation dispersion profiles arising from contributions to exchange from differences in methyl 1H chemical shifts between ground and excited states. The MQ 13C CPMG experiment is tested on two protein systems: (1) a triple mutant of the Fyn SH3 domain that interconverts slowly on the chemical shift time scale between the major folded state and an excited state folding intermediate; and (2) the 82-kDa enzyme Malate Synthase G (MSG), where chemical exchange at individual Ile δ1 methyl positions occurs on a much faster time-scale.

A Phase 1/2 Study of a Respiratory Syncytial Virus Prefusion F Vaccine With and Without Adjuvant in Healthy Older Adults.

BACKGROUND: Respiratory syncytial virus (RSV) is an important cause of disease in older adults. We evaluated the safety and immunogenicity of a stabilized RSV prefusion F subunit (RSVpreF) vaccine candidate with/without adjuvant in adults aged 65-85 years. METHODS: Primary cohort participants were equally randomized to 1 of 7 RSVpreF formulations: 60 µg with either Al(OH)3 or CpG/Al(OH)3, 120 µg with either Al(OH)3 or CpG/Al(OH)3, 240 µg with either Al(OH)3 or CpG/Al(OH)3, 240 µg unadjuvanted, or placebo, administered concomitantly with high-dose seasonal inactivated influenza vaccine (SIIV). Participants in the month 0,2 cohort were randomized to RSVpreF 240 µg with CpG/Al(OH)3 or placebo, administered at months 0 and 2. RESULTS: All RSVpreF vaccine candidates elicited robust and persistent serum neutralizing responses when administered alone or with SIIV. There was no notable difference in neutralizing response between the formulations, including those containing CpG. In the month 0,2 cohort, there was no booster effect of dose 2. SIIV responses were similar or slightly lower with concomitant administration of RSVpreF. Most systemic and local reactions were mild and more frequent after RSVpreF than placebo. CONCLUSIONS: RSVpreF formulations were well tolerated and elicited robust neutralizing responses in older adults; however, CpG/Al(OH)3 did not further enhance responses. Clinical Trials Registration. NCT03572062.

Tilted, Uninterrupted, Monomeric HIV-1 gp41 Transmembrane Helix from Residual Dipolar Couplings.

Cryo-electron microscopy and X-ray crystallography have shown that the pre- and postfusion states of the HIV-1 gp41 viral coat protein, although very different from one another, each adopt C3 symmetric structures. A stable homotrimeric structure for the transmembrane domain (TM) also was modeled and supported by experimental data. For a C3 symmetric structure, alignment in an anisotropic medium must be axially symmetric, with the unique axis of the alignment tensor coinciding with the C3 axis. However, NMR residual dipolar couplings (RDCs) measured under three different alignment conditions were found to be incompatible with C3 symmetry. Subsequent measurements by paramagnetic relaxation enhancement, analytical ultracentrifugation, and DEER EPR, indicate that the transmembrane domain is monomeric. 15N NMR relaxation data and RDCs show that TM is highly ordered and uninterrupted for a total length of 32 residues, extending well into the membrane proximal external region.

Co-Evolutionary Fitness Landscapes for Sequence Design.

Efficient and accurate models to predict the fitness of a sequence would be extremely valuable in protein design. We have explored the use of statistical potentials for the coevolutionary fitness landscape, extracted from known protein sequences, in conjunction with Monte Carlo simulations, as a tool for design. As proof of principle, we created a series of predicted high-fitness sequences for three different protein folds, representative of different structural classes: the GA (all-α) and GB (α/ß) binding domains of streptococcal protein G, and an SH3 (all-ß) domain. We found that most of the designed proteins can fold stably to the target structure, and a structure for a representative of each for GA, GB and SH3 was determined. Several of our designed proteins were also able to bind to native ligands, in some cases with higher affinity than wild-type. Thus, a search using a statistical fitness landscape is a remarkably effective tool for finding novel stable protein sequences.

Quantitative Resolution of Monomer-Dimer Populations by Inversion Modulated DEER EPR Spectroscopy.

A simple method, based on inversion modulated double electron-electron resonance electron paramagnetic resonance (DEER EPR) spectroscopy, is presented for determining populations of monomer and dimer in proteins (as well as any other biological macromolecules). The method is based on analysis of modulation depth versus electron double resonance (ELDOR) pulse flip angle. High accuracy is achieved by complete deuteration, extensive sampling of a large number of ELDOR pulse flip angle values, and combined analysis of differently labeled spin samples. We demonstrate the method using two different proteins: an obligate monomer exemplified by the small immunoglobulin binding B domain of protein A, and the p66 subunit of HIV-1 reverse transcriptase which exists as an equilibrium mixture of monomer and dimer species whose relative populations are affected by glycerol content. This information is crucial for quantitative analysis of distance distributions involving proteins that may exist as mixtures of monomer, dimer and high order multimers under the conditions of the DEER EPR experiment.

Long Distance Measurements up to 160†Šin the GroEL Tetradecamer Using Q-Band DEER EPR Spectroscopy.

Current distance measurements between spin-labels on multimeric protonated proteins using double electron-electron resonance (DEER) EPR spectroscopy are generally limited to the 15-60 Šrange. Here we show how DEER experiments can be extended to dipolar evolution times of ca. 80 µs, permitting distances up to 170 Što be accessed in multimeric proteins. The method relies on sparse spin-labeling, supplemented by deuteration of protein and solvent, to minimize the deleterious impact of multispin effects and substantially increase the apparent spin-label phase memory relaxation time, complemented by high sensitivity afforded by measurements at Q-band. We demonstrate the approach using the tetradecameric molecular machine GroEL as an example. Two engineered surface-exposed mutants, R268C and E315C, are used to measure pairwise distance distributions with mean values ranging from 20 to 100 Šand from 30 to 160 Å, respectively, both within and between the two heptameric rings of GroEL. The measured distance distributions are consistent with the known crystal structure of apo GroEL. The methodology presented here should significantly expand the use of DEER for the structural characterization of conformational changes in higher order oligomers.

The C34 Peptide Fusion Inhibitor Binds to the Six-Helix Bundle Core Domain of HIV-1 gp41 by Displacement of the C-Terminal Helical Repeat Region.

The conformational transition of the core domain of HIV-1 gp41 from a prehairpin intermediate to a six-helix bundle is responsible for virus-cell fusion. Several inhibitors which target the N-heptad repeat helical coiled-coil trimer that is fully accessible in the prehairpin intermediate have been designed. One such inhibitor is the peptide C34 derived from the C-heptad repeat of gp41 that forms the exterior of the six-helix bundle. Here, using a variety of biophysical techniques, including dye tagging, size-exclusion chromatography combined with multiangle light scattering, double electron-electron resonance EPR spectroscopy, and circular dichroism, we investigate the binding of C34 to two six-helix bundle mimetics comprising N- and C-heptad repeats either without (core(SP)) or with (core(S)) a short spacer connecting the two. In the case of core(SP), C34 directly exchanges with the C-heptad repeat. For core(S), up to two molecules of C34 bind the six-helix bundle via displacement of the C-heptad repeat. These results suggest that fusion inhibitors such as C34 can target a continuum of transitioning conformational states from the prehairpin intermediate to the six-helix bundle prior to the occurrence of irreversible fusion of viral and target cell membranes.

Dependence of distance distributions derived from double electron-electron resonance pulsed EPR spectroscopy on pulse-sequence time.

Pulsed double electron-electron resonance (DEER) provides pairwise P(r) distance distributions in doubly spin labeled proteins. We report that in protonated proteins, P(r) is dependent on the length of the second echo period T owing to local environmental effects on the spin-label phase memory relaxation time Tm . For the protein ABD, this effect results in a 1.4 Šincrease in the P(r) maximum from T=6 to 20 µs. Protein A has a bimodal P(r) distribution, and the relative height of the shorter distance peak at T=10 µs, the shortest value required to obtain a reliable P(r), is reduced by 40 % relative to that found by extrapolation to T=0. Our results indicate that data at a series of T values are essential for quantitative interpretation of DEER to determine the extent of the T dependence and to extrapolate the results to T=0. Complete deuteration (99 %) of the protein was accompanied by a significant increase in Tm and effectively abolished the P(r) dependence on T.

Proline Peptide Bond Isomerization in Ubiquitin Under Folding and Denaturing Conditions by Pressure-Jump NMR.

Proline isomerization is widely recognized as a kinetic bottleneck in protein folding, amplified for proteins rich in Pro residues. We introduced repeated hydrostatic pressure jumps between native and pressure-denaturing conditions inside an NMR sample cell to study proline isomerization in the pressure-sensitized L50A ubiquitin mutant. Whereas in two unfolded heptapeptides, X-Pro peptide bonds isomerized ca 1.6-fold faster at 1 bar than at 2.5 kbar, for ubiquitin ca eight-fold faster isomerization was observed for Pro-38 and ca two-fold for Pro-19 and Pro-37 relative to rates measured in the pressure-denatured state. Activation energies for isomerization in pressure-denatured ubiquitin were close to literature values of 20 kcal/mole for denatured polypeptides but showed a substantial drop to 12.7 kcal/mole for Pro-38 at atmospheric pressure. For ubiquitin isomers with a cis E18-P19 peptide bond, the 1-bar NMR spectrum showed sharp resonances with near random coil chemical shifts for the C-terminal half of the protein, characteristic of an unfolded chain, while most of the N-terminal residues were invisible due to exchange broadening, pointing to a metastable partially folded state for this previously recognized 'folding nucleus'. For cis-P37 isomers, a drop in pressure resulted in the rapid loss of nearly all unfolded-state NMR resonances, while the recovery of native state intensity revealed a slow component attributed to cis â†’ trans isomerization of P37. This result implies that the NMR-invisible cis-P37 isomer adopts a molten globule state that encompasses the entire length of the ubiquitin chain, suggestive of a structure that mostly resembles the folded state.

Efficacy and safety of bivalent RSVpreF maternal vaccination to prevent RSV illness in Japanese infants: Subset analysis from the pivotal randomized phase 3 MATISSE trial.

BACKGROUND: Maternal vaccination with respiratory syncytial virus prefusion F vaccine (RSVpreF) is effective at preventing RSV-associated lower respiratory tract illness (LRTI) in newborns/infants. METHODS: This subgroup analysis from the global, phase 3, randomized, double-blind, placebo-controlled MATISSE (Maternal Immunization Study for Safety and Efficacy) trial evaluated participants enrolled in Japan. Pregnant women 24-36 weeks' gestation were randomized 1:1 to receive RSVpreF or placebo. Maternal safety endpoints included local reactions/systemic events within 7 days, adverse events (AEs) through 1 month, and serious AEs (SAEs) through 6 months after vaccination. In infants born to maternal participants, safety endpoints included specific birth outcomes, AEs through 1 month after birth, and SAEs and newly diagnosed chronic medical conditions through 12 or 24 months after birth. Vaccine efficacy in infants was assessed against RSV-positive, medically attended LRTI (RSV-MA-LRTI) and severe RSV-MA-LRTI through 180 days after birth. RESULTS: In Japan, 230 maternal participants received RSVpreF and 232 received placebo; 218 and 216 infants born to these mothers, respectively, were analyzed. Observed vaccine efficacy (95 % CIs) against infant RSV-MA-LRTI within 90 and 180 days after birth was 100.0 % (30.9, 100.0; RSVpreF, 0 cases; placebo, 7 cases) and 87.6 % (7.2, 99.7; RSVpreF, 1 case; placebo, 8 cases), respectively. Vaccine efficacy (95 % CIs) against severe RSV-MA-LRTI within 90 and 180 days was 100.0 % (-140.9, 100.0; RSVpreF, 0 cases; placebo, 3 cases) and 75.1 % (-151.5, 99.5; RSVpreF, 1 case; placebo, 4 cases), respectively. No safety concerns were identified. AE rates ≤1 month after vaccination/birth were similar in the RSVpreF (maternal, 16.1 %; infant, 48.6 %) and placebo (19.8 %; 50.5 %) groups. Preterm birth rates were also similar (RSVpreF, 3.2 %; placebo, 6.0 %). CONCLUSIONS: Safety and efficacy data in Japanese participants were consistent with overall MATISSE results, supporting the efficacy of maternal RSVpreF vaccination against severe MA-RSV-LRTI/MA-RSV-LRTI in infants, with no safety concerns. NCT04424316.

Structure and dynamics of full-length HIV-1 capsid protein in solution.

The HIV-1 capsid protein plays a crucial role in viral infectivity, assembling into a cone that encloses the viral RNA. In the mature virion, the N-terminal domain of the capsid protein forms hexameric and pentameric rings, while C-terminal domain homodimers connect adjacent N-terminal domain rings to one another. Structures of disulfide-linked hexamer and pentamer assemblies, as well as structures of the isolated domains, have been solved previously. The dimer configuration in C-terminal domain constructs differs in solution (residues 144-231) and crystal (residues 146-231) structures by ∼30°, and it has been postulated that the former connects the hexamers while the latter links pentamers to hexamers. Here we study the structure and dynamics of full-length capsid protein in solution, comprising a mixture of monomeric and dimeric forms in dynamic equilibrium, using ensemble simulated annealing driven by experimental NMR residual dipolar couplings and X-ray scattering data. The complexity of the system necessitated the development of a novel computational framework that should be generally applicable to many other challenging systems that currently escape structural characterization by standard application of mainstream techniques of structural biology. We show that the orientation of the C-terminal domains in dimeric full-length capsid and isolated C-terminal domain constructs is the same in solution, and we obtain a quantitative description of the conformational space sampled by the N-terminal domain relative to the C-terminal domain on the nano- to millisecond time scale. The positional distribution of the N-terminal domain relative to the C-terminal domain is large and modulated by the oligomerization state of the C-terminal domain. We also show that a model of the hexamer/pentamer assembly can be readily generated with a single configuration of the C-terminal domain dimer, and that capsid assembly likely proceeds via conformational selection of sparsely populated configurations of the N-terminal domain within the capsid protein dimer.

Safety and Immunogenicity of the BNT162b2 Vaccine Coadministered with Seasonal Inactivated Influenza Vaccine in Adults.

INTRODUCTION: Vaccination is a critical tool for preventing coronavirus disease 2019 (COVID-19) and influenza illnesses. Coadministration of the COVID-19 vaccine, BNT162b2, with seasonal inactivated influenza vaccine (SIIV) can provide substantial benefits, including streamlining vaccine delivery. METHODS: In this phase 3 study, healthy 18- to 64-year-olds who had received three previous doses of BNT162b2 were randomized (1:1) to the coadministration group (month 0, BNT162b2 + SIIV; month 1, placebo) or the separate-administration group (month 0, placebo + SIIV; month 1, BNT162b2). The primary immunogenicity objective was to demonstrate that the immune responses elicited by BNT162b2 and SIIV [measured by full-length S-binding immunoglobulin G (IgG) levels and strain-specific hemagglutination inhibition assay (HAI) titers against four influenza strains 1 month post-vaccination, respectively] when coadministered were noninferior to those elicited by either vaccine administered alone, based on a prespecified 1.5-fold noninferiority margin [lower bound 95% CI for geometric mean ratio (GMR) > 0.67]. Reactogenicity and adverse event (AE) rates were evaluated. RESULTS: Randomized participants who received study vaccination (N = 1128; coadministration group, n = 564; separate-administration group, n = 564) had a median age of 39 years. Model-adjusted GMRs for coadministration to separate administration were 0.83 (95% CI 0.77, 0.89) for full-length S-binding IgG levels and 0.89-1.00 (lower bound of all 95% CIs > 0.67) for the four influenza strain-specific HAI titers, with all endpoints achieving the prespecified noninferiority criterion. Reactogenicity events were mostly mild or moderate when BNT162b2 was coadministered with SIIV. Serious AEs were reported in < 1% of participants within 1 month after any vaccination; none were considered vaccine-related. CONCLUSIONS: BNT162b2 coadministered with SIIV elicited immune responses that were noninferior to those elicited by BNT162b2 alone and SIIV alone, and BNT162b2 had an acceptable safety profile when coadministered with SIIV. The results of this study support the coadministration of BNT162b2 and SIIV in adults. TRIAL REGISTRATION: ClinicalTrials.gov registration: NCT05310084.

A randomized study to evaluate safety and immunogenicity of the BNT162b2 COVID-19 vaccine in healthy Japanese adults.

We report interim safety and immunogenicity findings from an ongoing phase 1/2 study of BNT162b2 in healthy Japanese adults. Participants were randomized 3:1 to receive 2 intramuscular injections of 30 µg BNT162b2 or placebo 21 days apart. Overall, 160 individuals were randomized: 119 received BNT162b2, and 41 received placebo. Participants were stratified by age: 20-64 years (n = 130) and 65-85 years (n = 30). More than 97% of BNT162b2 recipients received 2 doses. Local reactions and systemic events were generally transient and mild to moderate. Severe adverse events were uncommon; there were no serious adverse events. One month after dose 2, SARS-CoV-2 50% serum neutralizing geometric mean titers were 571 and 366, and geometric mean fold rises were 55.8 and 36.6, in the younger and older age groups, respectively. In summary, BNT162b2 has an acceptable safety profile and produces a robust immune response, regardless of age, in Japanese adults. (ClinicalTrials.gov, NCT04588480).

Persistence of Immune Responses Through 36 Months in Healthy Adults After Vaccination With a Novel Staphylococcus aureus 4-Antigen Vaccine (SA4Ag).

BACKGROUND: Staphylococcus aureus causes serious health care- and community-associated disease, requiring improved preventive measures such as vaccines. The investigational S. aureus 4-antigen vaccine (SA4Ag), comprising capsular polysaccharide serotypes 5 and 8 (CP5 and CP8) conjugated to CRM197, recombinant mutant clumping factor A (rmClfA), and recombinant manganese transporter protein C (rP305A or rMntC), was well tolerated, inducing robust functional immune responses to all 4 antigens through 12 months postvaccination. This is a serological extension study through 36 months postvaccination. METHODS: In 2 previous studies, healthy adults received SA4Ag, SA3Ag (without rMntC), or placebo; serology was also assessed at ~24 and ~36 months postvaccination. Functional immune responses (antibody responses that facilitate killing of S. aureus or neutralize S. aureus virulence mechanisms) were assessed with opsonophagocytic activity killing assays (CP5 or CP8) and a fibrinogen-binding inhibition assay (ClfA). A competitive Luminex immunoassay assessed ClfA and rMntC responses. Adverse events within 48 hours of blood draw were recorded. RESULTS: Four hundred forty subjects (18-64 years old, 255; 65-85 years old, 185) were enrolled. At 24 and 36 months postvaccination, subjects receiving SA4Ag had substantially higher geometric mean titers (GMTs) for CP5, CP8, and ClfA vs baseline; geometric mean fold rises (GMFRs) from baseline to month 36 were 2.7-8.1. For rMntC, 36-month GMTs declined from peak levels but remained above baseline for all SA4Ag groups; GMFRs from baseline to month 36 were 1.8 and 1.5 in the younger and older cohorts, respectively. CONCLUSIONS: Persistent functional immune responses to S. aureus antigens were observed through 36 months in healthy adults. CLINICALTRIALSGOV: NCT01643941 and NCT01364571.

S. aureus colonization in healthy Australian adults receiving an investigational S. aureus 3-antigen vaccine.

OBJECTIVES: Assess Staphylococcus aureus (S. aureus) colonization in healthy Australian adults receiving an investigational S. aureus 3-antigen vaccine (SA3Ag). METHODS: In this phase 1, double-blind, sponsor-unblinded study, participants were randomized to receive a single dose (1 of 3 dose levels) of SA3Ag or placebo and a booster dose or placebo at 6 months. S. aureus isolates from nasal, perineal, and oropharyngeal swabs before and through 12 months post-vaccination were identified. RESULTS: Baseline S. aureus colonization prevalence was 30.6% (any site), with nasal carriage (27.0%) more common than oropharyngeal/perineal (3.2% each). Following initial vaccination (low-dose: 102; mid-dose: 101; high-dose: 101; placebo: 102) and booster (low-dose: 45; mid-dose: 44; high-dose: 27; placebo: 181), placebo and SA3Ag groups showed similar S. aureus carriage through 12 months. Most colonized participants (74.0%) were colonized by single spa types. Placebo and SA3Ag groups had similar persistence of colonization, with 19.6-30.7% due to single spa types. Acquisition was observed in mid- and high-dose recipients (∼20%) and low-dose and placebo recipients (∼12%). Vaccination resulted in substantial increases in antibodies to all 3 antigens, irrespective of carriage status. CONCLUSIONS: Based on descriptive analyses of this small study, SA3Ag vaccination did not impact S. aureus acquisition or carriage. Carriage status did not impact antibody responses to SA3Ag.