RESUMO
Background: The SARS-CoV-2 pandemic has affected more than 250 million people worldwide resulting in 5 million deaths. To contain the pandemic, there is a continued need for safe vaccines that provide durable protection at low and scalable doses that easily delivered. Previously, we showed that an adeno-associated virus (AAV)-based vaccine candidate (AC1) elicited high humoral and cellular immunogenicity in mice and nonhuman primates (NHP) following a single injection, which provided near-sterilizing immunity against SARS-CoV-2 in NHP. Here, we developed optimized AAVCOVID vaccine candidates for higher potency and protection against variants of concern (VOC). Methods: The promoter in AC1 vector was substituted by three different promoters to increase the expression of Spike and they were tested in mice by single IM injection. Transgene expression and anti-Spike antibody and cellular responses were determined to assess vector potency. Then, the candidate that showed higher potency (ACM1) was engineered to express the Beta (ACM-Beta) and Delta (ACM-Delta) VOC Spike. The immunogenicity provided by ACM-Beta and ACM-Delta was characterized in mice and NHP. The cross-reactivity with the Wuhan and VOC Spikes was also assessed in the animals immunized with different Spike variants. Finally, challenge and durability studies were performed in NHPs vaccinated with the new candidates. Results: Vaccination with ACM1 candidate (miniCMV promoter) resulted in 100-fold higher Spike expression and 40-fold higher antibody responses compared to the prototypic AC1 candidate in mice. When ACM1, ACM-Beta and ACM-Delta were compared in mice, we found that the immune responses against the self-transgene were not significantly different. However, cross-reactivity was different, being ACM-Delta the candidate that better cross-neutralized the different VOC. Similar results were observed in NHP: higher potency of the candidates carrying the miniCMV promoter and similar cross-reactivity profiles. Additionally, ACM-Beta showed protection against Beta SARS-CoV-2 challenge and a durability study for ACM-Delta is ongoing. Conclusion: This work shows the adaptability and versatility of AAVCOVID vaccine platform to improve potency and protect against VOC. These observations together with the single, low dose requirement, high yield manufacturability, and 1-month stability for storage at room-temperature may make this technology well-suited to support effective immunization campaigns for emerging pathogens on a global scale.
RESUMO
The SARS-CoV-2 outbreak in December 2019 in China and its expansion across the world and Europe have requested the participation of clinical laboratories as major players in the diagnosis of COVID-19, to perform PCR tests mainly on nasopharyngeal swabs. In Belgium, the first confirmed COVID-19 patient was diagnosed in early February, the first of many, especially travelers returning from winter sports. In order to meet the ever-increasing demands for testing, the Clinical Microbiology Laboratory of the CHU of Liege had to adapt to this situation: firstly, by developing manual PCR tests and then automated solutions, permitting to increase the number of analyzes by ensuring a short turnaround time of results. Then, a system for the communication of results on a large scale has been set up, and finally solutions to deal with the lack of sampling devices have been found. This first wave of the pandemic has also highlighted an unprecedented solidarity within the institution. In this article, we recount the chronology of the management of this unprecedented health crisis within the Clinical Microbiology Laboratory of the CHU of Liege.
RESUMO
Chronicle of a crisis management at the Clinical Microbiology Laboratory of CHU Liege The SARS-CoV-2 outbreak in December 2019 in China and its expansion across the world and Europe have requested the participation of clinical laboratories as major players in the diagnosis of COVID-19, to perform PCR tests mainly on nasopharyngeal swabs. In Belgium, the first confirmed COVID-19 patient was diagnosed in early February, the first of many, especially travelers returning from winter sports. In order to meet the ever-increasing demands for testing, the Clinical Microbiology Laboratory of the CHU of Liege had to adapt to this situation: firstly, by developing manual PCR tests and then automated solutions, permitting to increase the number of analyzes by ensuring a short turnaround time of results. Then, a system for the communication of results on a large scale has been set up, and finally solutions to deal with the lack of sampling devices have been found. This first wave of the pandemic has also highlighted an unprecedented solidarity within the institution. In this article, we recount the chronology of the management of this unprecedented health crisis within the Clinical Microbiology Laboratory of the CHU of Liege.