Efficacy, safety, and immunogenicity of an inactivated, adjuvanted enterovirus 71 vaccine in infants and children: a multiregion, double-blind, randomised, placebo-controlled, phase 3 trial.

BACKGROUND: Children are susceptible to severe or fatal enterovirus 71 (EV71) infections. We aimed to evaluate the efficacy, safety, and immunogenicity of EV71vac, an aluminium phosphate-adjuvanted inactivated EV71 vaccine in children aged 2-71 months. METHODS: We did a randomised, double-blinded, placebo-controlled, phase 3 trial at five hospitals in Taiwan and two in Vietnam. Children aged 2-71 months were stratified by country and age, and randomly assigned (1:1) to receive two doses of EV71vac or placebo via intramuscular injection 56 days apart. Children aged 2-23 months received a third booster dose on day 366. The primary endpoint was the clinical efficacy of the total vaccinated cohort against EV71-associated diseases during the follow-up period, from 14 days after the second dose to when 15 cases of EV71 infections were confirmed in the per-protocol population. Our safety analysis included all participants who received at least one dose of EV71vac. This trial is registered with ClinicalTrials.gov, NCT03865238, and is complete. FINDINGS: Between April 23 and Dec 25, 2019, of 3663 children assessed, 3061 were randomly assigned, of whom 3049 were vaccinated: 1521 children in the EV71vac group and 1528 in the placebo group. By May 20, 2021, our primary efficacy analysis included 2959 children, with 1476 children in the EV71vac group and 1483 children in the placebo group. The vaccine efficacy of EV71vac was 96·8% (95% CI 85·5-100) against EV71 associated diseases (p<0·0001). The percentage of participants who reported solicited adverse events were similar in both groups: 865 (56·9%) in the EV71vac group and 852 (55·8%) in the placebo group. Almost all reported solicited adverse events were mild and self-limited. INTERPRETATION: EV71vac is safe, well-tolerated, and highly effective in preventing EV71 associated diseases in children aged 2-71 months. FUNDING: Medigen Vaccine Biologics and A+ Industrial Innovative R&D Program of the Ministry of Economic Affairs, Taiwan.

Altered pathogenicity for seasonal influenza virus by single reassortment of the RNP genes derived from the 2009 pandemic influenza virus.

BACKGROUND: The 2009 influenza A pandemic virus (H1N1(pdm)) may reassort with old seasonal influenza A virus (H1N1141) in humans and potentially change their pathogenicity. METHODS AND RESULTS: This study focuses on the reassortment of ribonucleoproteins (RNPs) among H1N1(pdm) and seasonal influenza A viruses. A single RNP gene reassortment altered reporter gene expression levels driven by polymerase complex in transfection system. The growth rates of recombinant viruses with different RNP recombinations were changed in A549 cells. Mice were infected with recombinant viruses containing single RNP gene reassortment, and pathogenicity was examined. The results demonstrated that the median lethal dose (LD50) of the PB2141/PB1141/PA(pdm)/NP141 recombinant virus was lower than that of the seasonal H1N1 virus. Viral titers of this reassorted virus in the lung and spleen were significantly higher than that in seasonal H1N1 virus-challenged mice. CONCLUSIONS: Although the changes of RNP activity did not exactly reflect to mice virulence, we consistently observed that the PA gene of H1N1(pdm) results in increased polymerase activity, better replication in mice, and lower LD50. Our findings suggest that monitoring of gene reassortment for the 2009 pandemic influenza and seasonal human viruses is also important, which would help to constrain the potential emergence of a more virulent influenza A variant.

Safety and immunogenicity of a Recombinant Stabilized Prefusion SARS-CoV-2 Spike Protein Vaccine (MVC-COV1901) Adjuvanted with CpG 1018 and Aluminum Hydroxide in healthy adults: A Phase 1, dose-escalation study.

BACKGROUND: This was a phase 1, dose-escalation open-label trial to evaluate the safety and immunogenicity of MVC-COV1901, a SARS-CoV-2 S-2P protein vaccine adjuvanted with aluminum hydroxide and CpG 1018. METHODS: Between September 28 and November 13 2020, 77 participants were screened. Of these, 45 healthy adults from 20 to 49 years of age were to be administered two doses of MVC-COV1901 in doses of 5 µg, 15 µg, or 25 µg of spike protein at 28 days apart. There were 15 participants in each dose group; all were followed for 28 days after the second dose at the time of the interim analysis. Adverse events and laboratory data were recorded for the safety evaluation. Blood samples were collected for humoral, and cellular immune response at various time points. Trial Registration: ClinicalTrials.gov NCT04487210. FINDINGS: Solicited adverse events were mostly mild and similar. No subject experienced fever. After the second dose, the geometric mean titers (GMTs) for SARS-CoV-2 spike-specific immunoglobulin G were 7178.2, 7746.1, 11,220.6 in the 5 µg, 15 µg, and 25 µg dose groups, respectively. The neutralizing activity were detected in both methods. (Day 43 GMTs, 538.5, 993.1, and 1905.8 for pseudovirus; and 33.3, 76.3, and 167.4 for wild-type virus). The cellular immune response induced by MVC-COV1901 demonstrated substantially higher numbers of IFN-γ- producing cells, suggesting a Th1-skewed immune response. INTERPRETATION: The MVC-COV1901 vaccine was well tolerated and elicited robust immune responses and is suitable for further development. FUNDING: Medigen Vaccine Biologics Corporation.

Immunogenicity, safety, cross-reaction, and immune persistence of an inactivated enterovirus A71 vaccine in children aged from two months to 11 years in Taiwan.

BACKGROUND: To fight against enterovirus A71 (EV-A71)-associated diseases, vaccine development was initiated in Taiwan focusing on two-month-old infants. METHODS: We conducted a phase II, double-blind, randomised, placebo-controlled study on infants and children aged two months to 11 years. This study was conducted in 4 parts (2a, 2b, 2c, and 2d) with age de-escalation sequentially. Two doses were administered with a 28-day or 56-day interval. Participants aged two months to

The safety and immunogenicity of a cell-derived adjuvanted H5N1 vaccine - A phase I randomized clinical trial.

BACKGROUND: Development of an efficacious egg-free mock-up H5N1 vaccine is key to our preparedness against pandemic avian flu. METHODS: This is a single-center, randomized, observer-blinded phase I clinical trial evaluating the safety and immunogenicity of an alum-adjuvanted Madin-Darby canine kidney (MDCK)-derived inactivated whole-virion H5N1 influenza vaccine in healthy adults. Hemagglutination inhibition (HAI) and neutralizing antibody titers were measured using horse and turkey red blood cells (RBCs). RESULTS: Thirty-six adult subjects were randomized to receive two doses of 0.5 mL of the MDCK-derived H5N1 alum-adjuvanted vaccine containing 7.5, 15, or 30 µg of hemagglutinin (HA) 21 days apart. The candidate vaccine was well tolerated and safe across the three dosing groups. The most frequent adverse event was injection site pain (46.5%). Both HAI and neutralizing antibody titers increased after each vaccination in all three dosing groups. The best HAI responses, namely a seroconversion rate of 91.7% and a geometric mean ratio of 9.51 were achieved with the HA dose of 30 µg assayed using horse RBCs at day 42. HAI titers against H5N1 avian influenza virus was significantly higher when measured using horse RBCs compared with turkey RBCs. CONCLUSIONS: This Phase I trial showed the MDCK-derived H5N1 candidate vaccine is safe and immunogenic. The source of RBCs has a significant impact on the measurement of HAI titers (ClinicalTrials.gov number: NCT01675284.).

Detection of low copies of drug-resistant influenza viral gene by a single-tube reaction using peptide nucleic acid as both PCR clamp and sensor probe.

Influenza virus infection causes endemics almost yearly and pandemics occasionally. Although antivirals are available for the clinical treatment of influenza virus infection, the emergence of a drug-resistant virus has reduced the effectiveness of therapy and prophylaxis. Therefore, the timely detection of drug-resistant influenza viruses is important. A single-tube reaction using peptide nucleic acid (PNA) as both a polymerase chain reaction (PCR) clamp and a sensor probe was established to detect the low numbers of copies of viral genes that carry the resistant marker. Influenza A H1N1 viruses resistant to a clinically used antiviral, amantadine, are selected for the experimental design. The PNA-mediated reverse transcription-PCR detected 10 copies/µL of RNA from the resistant strain among 2 × 10(4) copies/µL of RNA from the sensitive strain. A rapid and sensitive method was established for detecting low numbers of drug-resistant genes of the influenza virus. The assay would help to monitorthe emergence of adrug-resistant influenza virus.