Immunogenicity and Safety of Heterologous Omicron BA.1 and Bivalent SARS-CoV-2 Recombinant Spike Protein Booster Vaccines: A Phase 3 Randomized Clinical Trial.

BACKGROUND: Mutations present in emerging SARS-CoV-2 variants permit evasion of neutralization with prototype vaccines. A novel Omicron BA.1 subvariant-specific vaccine (NVX-CoV2515) was tested alone or as a bivalent preparation with the prototype vaccine (NVX-CoV2373) to assess antibody responses to SARS-CoV-2. METHODS: Participants aged 18 to 64 years immunized with 3 doses of prototype mRNA vaccines were randomized 1:1:1 to receive a single dose of NVX-CoV2515, NVX-CoV2373, or the bivalent mixture in a phase 3 study investigating heterologous boosting with SARS-CoV-2 recombinant spike protein vaccines. Immunogenicity was measured 14 and 28 days after vaccination for the SARS-CoV-2 Omicron BA.1 sublineage and ancestral strain. Safety profiles of vaccines were assessed. RESULTS: Of participants who received trial vaccine (N = 829), those administered NVX-CoV2515 (n = 286) demonstrated a superior neutralizing antibody response to BA.1 vs NVX-CoV2373 (n = 274) at day 14 (geometric mean titer ratio, 1.6; 95% CI, 1.33-2.03). Seroresponse rates were 73.4% (91/124; 95% CI, 64.7-80.9) for NVX-CoV2515 vs 50.9% (59/116; 95% CI, 41.4-60.3) for NVX-CoV2373. All formulations were similarly well tolerated. CONCLUSIONS: NVX-CoV2515 elicited a superior neutralizing antibody response against the Omicron BA.1 subvariant as compared with NVX-CoV2373 when administered as a fourth dose. Safety data were consistent with the established safety profile of NVX-CoV2373. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov (NCT05372588).

Effect of Starch and Paperboard Reinforcing Structures on Insulative Fiber Foam Composites.

Single-use plastic foams are used extensively as interior packaging to insulate and protect items during shipment but have come under increasing scrutiny due to the volume sent to landfills and their negative impact on the environment. Insulative compression molded cellulose fiber foams could be a viable alternative, but they do not have the mechanical strength of plastic foams. To address this issue, a novel approach was used that combined the insulative properties of cellulose fiber foams, a binder (starch), and three different reinforcing paperboard elements (angular, cylindrical, and grid) to make low-density foam composites with excellent mechanical strength. Compression molded foams and composites had a consistent thickness and a smooth, flat finish. Respirometry tests showed the fiber foams mineralized in the range of 37 to 49% over a 46 d testing period. All of the samples had relatively low density (Dd) and thermal conductivity (TC). The Dd of samples ranged from 33.1 to 64.9 kg/m3, and TC ranged from 0.039 to 0.049 W/mk. The addition of starch to the fiber foam (FF+S) and composites not only increased Dd, drying time (Td), and TC by an average of 18%, 55%, and 5.5%, respectively, but also dramatically increased the mechanical strength. The FF+S foam and paperboard composites had 240% and 350% higher average flexural strength (σfM) and modulus (Ef), respectively, than the FF-S composites. The FF-S grid composite and all the FF+S foam and composite samples had equal or higher σfM than EPS foam. Additionally, FF+S foam and paperboard composites had 187% and 354% higher average compression strength (CS) and modulus (Ec), respectively, than the FF-S foam and composites. All the paperboard composites for both FF+S and FF-S samples had comparable or higher CS, but only the FF+S cylinder and grid samples had greater toughness (Ωc) than EPS foam. Fiber foams and foam composites are compatible with existing paper recycling streams and show promise as a biodegradable, insulative alternative to EPS foam internal packaging.

Immunogenicity and safety of a bivalent (omicron BA.5 plus ancestral) SARS-CoV-2 recombinant spike protein vaccine as a heterologous booster dose: interim analysis of a phase 3, non-inferiority, randomised, clinical trial.

BACKGROUND: SARS-CoV-2 variants evade immunity despite vaccination with prototype COVID-19 vaccines or previous infection. The 2019nCoV-311 (part 2) study is evaluating immune responses after two booster doses of a vaccine containing the omicron BA.5 subvariant spike protein in adults previously vaccinated with a prototype mRNA vaccine. This interim analysis reports on day 28 immunogenicity and safety outcomes after one booster dose. METHODS: In this phase 3, randomised, observer-blinded study conducted at 35 sites in Australia, medically stable, previously COVID-19-vaccinated (mRNA-based; ≥three doses) adults aged 18 years or older were enrolled and randomly allocated (1:1:1; via an interactive web response system) to receive two doses of bivalent (NVX-CoV2373 + NVX-CoV2540; bivalent group), authorised prototype (NVX-CoV2373; prototype group), or BA.5 (NVX-CoV2540; BA.5 group) vaccine. Only blinded personnel performed study assessments or had participant contact to collect data after study vaccination. Participants received vaccines containing 5 µg SARS-CoV-2 recombinant spike protein and 50 µg Matrix-M adjuvant, administered via a 0·5 mL intramuscular injection (2·5 µg of NVX-CoV2373 plus 2·5 µg of NVX-CoV2540 for the bivalent vaccine, prepared on-site as a 1:1 mixture). The coprimary endpoints include day 28 neutralising antibody geometric mean titre (GMT) ratios (GMTRs) to omicron BA.5 and the ancestral strain, and seroresponse rates to BA.5, in the bivalent and prototype groups. These endpoints were calculated in the per-protocol analysis set, which was defined as participants who had received a vaccine dose, had baseline and day 28 immunogenicity data, and were PCR-negative for SARS-CoV-2, with no major protocol deviations. The primary objective was to determine the primary outcome (antibody responses), which consisted of three comparisons: superiority of the bivalent versus prototype vaccine for neutralising antibody GMT to BA.5 (ie, lower bound of the GMTR 95% CI >1·0); non-inferiority of neutralising antibody seroresponse rate to BA.5 (ie, lower bound of the seroresponse rate 95% CI >-5%); and non-inferiority of neutralising antibody GMT to the ancestral strain (ie, lower bound of GMTR 95% CI >0·67). This trial was registered at ClinicalTrials.gov, number NCT05372588. FINDINGS: Between March 22, 2023 and May 2, 2023, 837 participants were screened for eligibility and 766 were randomly allocated to receive the BA.5 (n=255), prototype (n=252), or bivalent (n=259) vaccine. After accounting for exclusions due to participants being baseline SARS-CoV-2-positive, having previous infection, or protocol deviations, the per-protocol analysis set included 694 participants (236 in BA.5 group, 227 in prototype group, and 231 in bivalent group). In this interim analysis (maximum follow-up 35 days after the first dose), the bivalent group, compared with the prototype group, had superior neutralising antibody responses to BA.5 (GMT 1017·8 [95% CI 891·0-1162·6] vs 515·1 [450·4-589·0]; GMTR 2·0 [1·69-2·33]) and a non-inferior seroresponse rate to BA.5 at day 28 (39·8% [33·5-46·5] vs 12·3% [8·4-17·3]; difference 27·5% [19·8-35·0]). The bivalent group also had non-inferior neutralising antibody responses to the ancestral strain (GMTR 1·0 [0·84-1·20]), compared with the prototype group. All vaccines were similarly well tolerated. INTERPRETATION: All three coprimary endpoints were met in part 2 of the ongoing 2019nCoV-311 study. These data support the development of monovalent and/or bivalent vaccines for the most currently circulating variants, to optimise protection. With no new safety findings, further investigation of omicron-based subvariant vaccines is supported by the evidence. FUNDING: Novavax.