ABSTRACT
Despite the remarkable efficacy of COVID-19 vaccines, waning immunity, and the emergence of SARS-CoV-2 variants such as Omicron represents a major global health challenge. Here we present data from a study in non-human primates demonstrating durable protection against the Omicron BA.1 variant induced by a subunit SARS-CoV-2 vaccine, consisting of RBD (receptor binding domain) on the I53-50 nanoparticle, adjuvanted with AS03, currently in Phase 3 clinical trial (NCT05007951). Vaccination induced robust neutralizing antibody (nAb) titers that were maintained at high levels for at least one year after two doses (Pseudovirus nAb GMT: 2207, Live-virus nAb GMT: 1964) against the ancestral strain, but not against Omicron. However, a booster dose at 6-12 months with RBD-Wu or RBD-{beta} (RBD from the Beta variant) displayed on I53-50 elicited equivalent and remarkably high neutralizing titers against the ancestral as well as the Omicron variant. Furthermore, there were substantial and persistent memory T and B cell responses reactive to Beta and Omicron variants. Importantly, vaccination resulted in protection against Omicron infection in the lung (no detectable virus in any animal) and profound suppression of viral burden in the nares (median peak viral load of 7567 as opposed to 1.3x107 copies in unvaccinated animals) at 6 weeks post final booster. Even at 6 months post vaccination, there was significant protection in the lung (with 7 out of 11 animals showing no viral load, 3 out of 11 animals showing ~20-fold lower viral load than unvaccinated controls) and rapid control of virus in the nares. These results highlight the durable cross-protective immunity elicited by the AS03-adjuvanted RBD-I53-50 nanoparticle vaccine platform.
Subject(s)
Memory Disorders , COVID-19ABSTRACT
BackgroundVaccines may elicit long-term boosting of innate immune responses that can help protect against COVID-19. We evaluated the association between recombinant adjuvanted zoster vaccine (RZV) and COVID-19 outcomes at Kaiser Permanente Southern California. MethodsIn a cohort design, adults aged [≥]50 years who received [≥]1 RZV dose prior to 3/1/2020 were matched 1:2 to unvaccinated individuals and followed until 12/31/2020. Adjusted hazard ratios (aHR) and 95% confidence intervals (CIs) for COVID-19 outcomes were estimated using Cox proportional hazards regression. In a test-negative design, cases had a positive SARS-CoV-2 test and controls had only negative tests, from 3/1/2020-12/31/2020. Adjusted odds ratios (aOR) and 95% CIs for prior receipt of RZV were estimated using logistic regression. ResultsIn the cohort design, 149,244 RZV recipients were matched to 298,488 unvaccinated individuals. The aHRs (95% CI) for COVID-19 diagnosis and hospitalization were 0.84 (0.81-0.87) and 0.68 (0.64-0.74), respectively. In the test-negative design, 8.4% of 75,726 test-positive cases and 13.1% of 340,898 test-negative controls had received [≥]1 RZV dose. The aOR (95% CI) was 0.84 (0.81-0.86). ConclusionRZV vaccination was associated with a 16% lower risk of COVID-19 diagnosis and 32% lower risk of hospitalization, suggesting RZV elicits heterologous protection, possibly through trained immunity.
Subject(s)
COVID-19ABSTRACT
As the SARS-COV-2 pandemic evolves, what is expected of vaccines extends beyond efficacy and includes evaluations of both durability and cross-reactivity to emerging variants. To complement an on-going Phase 3 efficacy study, this report expands on previously reported immunogenicity results from a Phase 1 trial of an AS03-adjuvanted, plant-based virus-like particle (VLP) displaying the spike glycoprotein of the Wuhan strain of SARS-CoV-2 virus (NCT04450004). Durability of the humoral and cellular responses against the ancestral strain was evaluated 6 months post-second dose (Day 201) at which time [~]94% of vaccinated individuals remained seropositive. Interferon gamma (IFN-{gamma}) and interleukin 4 (IL-4) responses remained detectable in [~]94% and [~]92% of vaccinated individuals respectively. Cross-reactivity of neutralizing antibodies to Alpha (B.1.17), Beta (B.1.351), and Gamma (P.1) variants of concern (VOC) were also measured. Twenty-one days after the second vaccination, detectable neutralizing antibodies were observed to the Alpha variant by both pseudovirion and wild-type assays for all vaccinated individuals, while 94.7% of individuals had detectable antibodies to the Beta variant in both assays. Neutralizing antibodies to the Gamma variant were detected in 100% and 94.7% of individuals using the pseudovirion and live virus neutralization assays, respectively. In all cases, the vaccine-induced neutralizing GMTs to the VOC 3 weeks post-vaccination were greater than the Wuhan-specific neutralization titers seen in individuals recovered from COVID-19.
Subject(s)
COVID-19ABSTRACT
The rapid spread of SARS-CoV-2 globally continues to impact humanity on a global scale with rising morbidity and mortality. Despite the development of multiple effective vaccines, new vaccines continue to be required to supply ongoing demand. We report Day 42 interim safety and immunogenicity data from a Phase 2, randomized, placebo-controlled trial in Adults aged 18+ immunized with a virus-like particle vaccine candidate produced in plants displaying SARS-CoV-2 spike glycoprotein (CoVLP) adjuvanted with AS03 (NCT04636697). This report focuses on presenting safety, tolerability and immunogenicity, as measured by neutralizing antibody (NAb) and cell mediated immunity (IFN-{gamma} and IL-4 ELISpot) responses, in Adults aged 18-64 (Adults) and Older Adults aged 65+ (Older Adults). CoVLP adjuvanted with AS03 was well-tolerated and adverse events (AE) were primarily mild or moderate and of transient duration. AEs in Older Adults were more limited than those observed in the Adult population. CoVLP with AS03 induced a significant humoral immune response in both age cohorts. CoVLP with AS03 induced a greater humoral response in Adults than Older Adults after a single dose but this effect was overcome with a second dose when both age cohorts responded with NAb titers that were ~10-fold higher than those in a panel of sera from patients recovering from COVID-19. A single dose of CoVLP with AS03 induced a significant IFN-{gamma} response in both age cohorts; a second dose significantly boosted IFN-{gamma} and IL-4 responses in both age cohorts. Adults generated a stronger IFN-{gamma} and IL-4 cellular response than did Older Adults after one or two doses of AS03-adjuvanted CoVLP. Safety and immunogenicity from Adults with comorbidities as well as final safety and immunogenicity responses after 12 months will be reported upon availability.
Subject(s)
COVID-19ABSTRACT
Understanding the ability of SARS-CoV-2 vaccine-elicited antibodies to neutralize and protect against emerging variants of concern and other sarbecoviruses is key for guiding vaccine development decisions and public health policies. We show that a clinical stage multivalent SARS-CoV-2 receptor-binding domain nanoparticle vaccine (SARS-CoV-2 RBD-NP) protects mice from SARS-CoV-2-induced disease after a single shot, indicating that the vaccine could allow dose-sparing. SARS-CoV-2 RBD-NP elicits high antibody titers in two non-human primate (NHP) models against multiple distinct RBD antigenic sites known to be recognized by neutralizing antibodies. We benchmarked NHP serum neutralizing activity elicited by RBD-NP against a lead prefusion-stabilized SARS-CoV-2 spike immunogen using a panel of single-residue spike mutants detected in clinical isolates as well as the B.1.1.7 and B.1.351 variants of concern. Polyclonal antibodies elicited by both vaccines are resilient to most RBD mutations tested, but the E484K substitution has similar negative consequences for neutralization, and exhibit modest but comparable neutralization breadth against distantly related sarbecoviruses. We demonstrate that mosaic and cocktail sarbecovirus RBD-NPs elicit broad sarbecovirus neutralizing activity, including against the SARS-CoV-2 B.1.351 variant, and protect mice against severe SARS-CoV challenge even in the absence of the SARS-CoV RBD in the vaccine. This study provides proof of principle that sarbecovirus RBD-NPs induce heterotypic protection and enables advancement of broadly protective sarbecovirus vaccines to the clinic.
Subject(s)
Severe Acute Respiratory SyndromeABSTRACT
Adjuvanted soluble protein vaccines have been used extensively in humans for protection against various viral infections based on their robust induction of antibody responses. Here, soluble prefusion-stabilized spike trimers (preS dTM) from the severe acute respiratory syndrome coronavirus (SARS-CoV-2) were formulated with the adjuvant AS03 and administered twice to nonhuman primates (NHP). Binding and functional neutralization assays and systems serology revealed that NHP developed AS03-dependent multi-functional humoral responses that targeted multiple spike domains and bound to a variety of antibody FC receptors mediating effector functions in vitro. Pseudovirus and live virus neutralizing IC50 titers were on average greater than 1000 and significantly higher than a panel of human convalescent sera. NHP were challenged intranasally and intratracheally with a high dose (3x106 PFU) of SARS-CoV-2 (USA-WA1/2020 isolate). Two days post-challenge, vaccinated NHP showed rapid control of viral replication in both the upper and lower airways. Notably, vaccinated NHP also had increased spike-specific IgG antibody responses in the lung as early as 2 days post challenge. Moreover, vaccine-induced IgG mediated protection from SARS-CoV-2 challenge following passive transfer to hamsters. These data show that antibodies induced by the AS03-adjuvanted preS dTM vaccine are sufficient to mediate protection against SARS-CoV-2 and support the evaluation of this vaccine in human clinical trials.
Subject(s)
Severe Acute Respiratory SyndromeABSTRACT
The development of a portfolio of SARS-CoV-2 vaccines to vaccinate the global population remains an urgent public health imperative. Here, we demonstrate the capacity of a subunit vaccine under clinical development, comprising the SARS-CoV-2 Spike protein receptor-binding domain displayed on a two-component protein nanoparticle (RBD-NP), to stimulate robust and durable neutralizing antibody (nAb) responses and protection against SARS-CoV-2 in non-human primates. We evaluated five different adjuvants combined with RBD-NP including Essai O/W 1849101, a squalene-in-water emulsion; AS03, an alpha-tocopherol-containing squalene-based oil-in-water emulsion used in pandemic influenza vaccines; AS37, a TLR-7 agonist adsorbed to Alum; CpG 1018-Alum (CpG-Alum), a TLR-9 agonist formulated in Alum; or Alum, the most widely used adjuvant. All five adjuvants induced substantial nAb and CD4 T cell responses after two consecutive immunizations. Durable nAb responses were evaluated for RBD-NP/AS03 immunization and the live-virus nAb response was durably maintained up to 154 days post-vaccination. AS03, CpG-Alum, AS37 and Alum groups conferred significant protection against SARS-CoV-2 infection in the pharynges, nares and in the bronchoalveolar lavage. The nAb titers were highly correlated with protection against infection. Furthermore, RBD-NP when used in conjunction with AS03 was as potent as the prefusion stabilized Spike immunogen, HexaPro. Taken together, these data highlight the efficacy of the RBD-NP formulated with clinically relevant adjuvants in promoting robust immunity against SARS-CoV-2 in non-human primates.