Dataset Information

SARS-CoV-2 Vaccine Effectiveness against Omicron Variant in Infection-Naive Population, Australia, 2022.

ABSTRACT: SARS-CoV-2 transmission in Western Australia, Australia, was negligible until a wave of Omicron variant infections emerged in February 2022, when >90% of adults had been vaccinated. This unique pandemic enabled assessment of SARS-CoV-2 vaccine effectiveness (VE) without potential interference from background immunity from prior infection. We matched 188,950 persons who had a positive PCR test result during February-May 2022 to negative controls by age, week of test, and other possible confounders. Overall, 3-dose VE was 42.0% against infection and 81.7% against hospitalization or death. A primary series of 2 viral-vectored vaccines followed by an mRNA booster provided significantly longer protection against infection >60 days after vaccination than a 3-dose series of mRNA vaccine. In a population free from non-vaccine-derived background immunity, vaccines against the ancestral spike protein were ≈80% effective for preventing serious outcomes from infection with the SARS-CoV-2 Omicron variant.

SUBMITTER: Bloomfield LE

PROVIDER: S-EPMC10202853 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature

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SARS-CoV-2 Vaccine Effectiveness against Omicron Variant in Infection-Naive Population, Australia, 2022.

Bloomfield Lauren E LE Ngeh Sera S Cadby Gemma G Hutcheon Kate K Effler Paul V PV

Emerging infectious diseases 20230504 6

SARS-CoV-2 transmission in Western Australia, Australia, was negligible until a wave of Omicron variant infections emerged in February 2022, when >90% of adults had been vaccinated. This unique pandemic enabled assessment of SARS-CoV-2 vaccine effectiveness (VE) without potential interference from background immunity from prior infection. We matched 188,950 persons who had a positive PCR test result during February-May 2022 to negative controls by age, week of test, and other possible confounder ...[more]

PMID: 37141626

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Project description:Mucosal immunity plays a pivotal role in providing comprehensive protection against upper-airway infections and effectively limiting the shedding and transmission of SARS-CoV-2. Despite its critical importance, there remains a notable absence of nasal spray vaccines endorsed for global use by the World Health Organization. This could be due to the inability of current intranasal vaccines to induce strong mucosal and systemic responses in humans, thus urgently entailing a next-generation of intranasal COVID-19 vaccines with novel and safe technologies. In this study, we prepared a two-component intranasal vaccine that combines adenovirus vectors with a self-assembled subunit protein. Specifically, the adenovirus vector expresses the spike protein of XBB.1.5 variant (Ad5XBB.1.5), and were mixed with the recombinant protein that developed derived from the receptor binding domain (RBD) of XBB.1.5 (RBDXBB.1.5-HR). Combination of Ad5XBB.1.5 and RBDXBB.1.5-HR elicited superior humoral and cellular immunity against XBB.1.5-included variants compared with the individual components. Importantly, the STING signaling pathway was found to be crucial for the adjuvant effect of the adenovirus vector. In addition, to increase the broad-spectrum neutralizing capacities, a trimeric protein derived from the BA.5 variant (RBDBA.5-HR) was incorporated to formulate a three-component vaccine (Ad5XBB.1.5+RBDXBB.1.5-HR+RBDBA.5-HR), indicating the utilization of a combination of an adenovirus-vectored and subunit protein vaccines has the potential to serve as a next-generation intranasal vaccine platform. Of note, intranasally delivery of two-component vaccine provided protective immunity against live Omicron XBB.1.16 virus challenge in mice. Furthermore, the combination of adenovirus and subunit protein vaccine demonstrates excellent tolerability and safety in human subjects, and is able to induce enhanced mucosal immunity as well as high levels of sera neutralizing antibody in all participants. These findings underscore its suitability for clinical application in the prevention of SARS-CoV-2 variants encompassing XBB lineages.

Project description:We aim to estimate the effectiveness of 2-dose and 3-dose mRNA vaccination (BNT162b2 and mRNA-1273) against general Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection (asymptomatic or symptomatic) caused by the omicron BA.1 variant. This propensity-score matched retrospective cohort study takes place in a large public university undergoing weekly Coronavirus Disease 2019 (Covid-19) testing in South Carolina, USA. The population consists of 24,145 university students and employees undergoing weekly Covid-19 testing between January 3rd and January 31st, 2022. The analytic sample was constructed via propensity score matching on vaccination status: unvaccinated, completion of 2-dose mRNA series (BNT162b2 or mRNA-1273) within the previous 5 months, and receipt of mRNA booster dose (BNT162b2 or mRNA-1273) within the previous 5 months. The resulting analytic sample consists of 1,944 university students (mean [SD] age, 19.64 [1.42] years, 66.4% female, 81.3% non-Hispanic White) and 658 university employees (mean [SD] age, 43.05 [12.22] years, 64.7% female, 83.3% non-Hispanic White). Booster protection against any SARS-CoV-2 infection was 66.4% among employees (95% CI: 46.1-79.0%; P<.001) and 45.4% among students (95% CI: 30.0-57.4%; P<.001). Compared to the 2-dose mRNA series, estimated increase in protection from the booster dose was 40.8% among employees (P=.024) and 37.7% among students (P=.001). We did not have enough evidence to conclude a statistically significant protective effect of the 2-dose mRNA vaccination series, nor did we have enough evidence to conclude that protection waned in the 5-month period after receipt of the 2nd or 3rd mRNA dose. Furthermore, we did not find evidence that protection varied by manufacturer. We conclude that in adults 18-65 years of age, Covid-19 mRNA booster doses offer moderate protection against general SARS-CoV-2 infection caused by the omicron variant and provide a substantial increase in protection relative to the 2-dose mRNA vaccination series.

Dataset Information

SARS-CoV-2 Vaccine Effectiveness against Omicron Variant in Infection-Naive Population, Australia, 2022.

Publications

SARS-CoV-2 Vaccine Effectiveness against Omicron Variant in Infection-Naive Population, Australia, 2022.

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