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Vaccine ; 40(26): 3597-3604, 2022 06 09.
Article in English | MEDLINE | ID: covidwho-1873314


BACKGROUND: At least one-half of adults beginning an immunization series with a three-dose hepatitis B virus (HBV) vaccine (ENGERIX-B, RECOMBIVAX-B) have been reported not to receive the third dose. Use of a two-dose vaccine may improve adherence and lead to greater overall levels of seroprotection. OBJECTIVE: To examine expected levels of adherence and overall seroprotection at one year among adults in routine clinical settings beginning an immunization series with either ENGERIX-B or the two-dose HBV vaccine, HEPLISAV-B. METHODS: Decision-analytic model comparing expected levels of adherence and overall seroprotection at one year among a hypothetical cohort of one million previously unvaccinated adults aged ≥ 30 years receiving first doses of either ENGERIX-B or HEPLISAV-B in a routine clinical setting. We stratified the population by age (30-49 years vs ≥ 50 years) to allow for possible differences in adherence and seroprotection. We estimated our model using published adherence rates for HBV vaccines, and reported seroprotection rates by number of doses administered. We also compared total expected costs of HBV immunization with each vaccine. RESULTS: Use of a two-dose rather than three-dose HBV vaccine would increase the expected number of adults seroprotected at one year by 275,000 per one million persons beginning immunization series, largely reflecting a gain of 290,000 in the expected number of persons fully vaccinated. Results were similar for the two age groups. While the cost per dose of HEPLISAV-B exceeds that of ENGERIX-B, its estimated mean cost per person seroprotected at one year is $50-$70 (∼15%) lower. CONCLUSIONS: Use of a two-dose HBV vaccine would increase the number of adults fully seroprotected at one year compared with the number expected with a three-dose vaccine. Notwithstanding its higher unit cost, mean expected cost per person seroprotected is substantially lower for HEPLISAV-B than ENGERIX-B as a result of much higher levels of seroprotection.

Hepatitis B Vaccines , Hepatitis B , Adult , Cohort Studies , Hepatitis B/prevention & control , Hepatitis B Antibodies , Hepatitis B Surface Antigens , Humans , Immunization , Immunization Schedule
Vaccines (Basel) ; 10(5)2022 Apr 21.
Article in English | MEDLINE | ID: covidwho-1847411


Rapid development and deployment of vaccines is crucial to control the continuously evolving COVID-19 pandemic. The placebo-controlled phase 3 efficacy trial is still the standard for authorizing vaccines in the majority of the world. However, due to a lack of eligible participants in parts of the world, this has not always been feasible. Recently, the Taiwan Food and Drug Administration, following the consensus of the International Coalition of Medicines Regulatory Authorities (ICMRA), adopted the use of immunobridging studies as acceptable for authorizing COVID-19 vaccines in lieu of efficacy data. Here, we describe a study in which our candidate vaccine, MVC-COV1901, an adjuvanted protein subunit vaccine, has been granted emergency use authorization (EUA) in Taiwan based on a noninferiority immunobridging study. Immunogenicity results from the per protocol immunogenicity (PPI) subset (n = 903) from the MVC-COV1901 phase 2 trial were compared with results from 200 subjects who had received an adenovirus vector vaccine, AstraZeneca ChAdOx nCOV-19 (AZD1222), in a separate study. The lower bound of the 95% confidence interval (CI) of the geometric mean titer (GMT) ratio comparing MVC-COV1901 to AZD1222 was 3.4. The lower bound of the 95% CI of the sero-response rate was 95.5%. Both the GMT ratio and sero-response rate exceeded the criteria established by the Taiwan regulatory authority, leading to EUA approval of MVC-COV1901 in Taiwan.

EClinicalMedicine ; 38: 100989, 2021 Aug.
Article in English | MEDLINE | ID: covidwho-1375926


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: 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.