Project description:Prime-boost regimens for COVID-19 vaccines elicit poor antibody responses against Omicron-based variants and employ frequent boosters to maintain antibody levels. We present a natural infection-mimicking technology that combines features of mRNA- and protein nanoparticle-based vaccines through encoding self-assembling enveloped virus-like particles (eVLPs). eVLP assembly is achieved by inserting an ESCRT- and ALIX-binding region (EABR) into the SARS-CoV-2 spike cytoplasmic tail, which recruits ESCRT proteins to induce eVLP budding from cells. Purified spike-EABR eVLPs presented densely arrayed spikes and elicited potent antibody responses in mice. Two immunizations with mRNA-LNP encoding spike-EABR elicited potent CD8+ T cell responses and superior neutralizing antibody responses against original and variant SARS-CoV-2 compared with conventional spike-encoding mRNA-LNP and purified spike-EABR eVLPs, improving neutralizing titers >10-fold against Omicron-based variants for 3 months post-boost. Thus, EABR technology enhances potency and breadth of vaccine-induced responses through antigen presentation on cell surfaces and eVLPs, enabling longer-lasting protection against SARS-CoV-2 and other viruses.
Project description:Viral variants of concern may emerge with dangerous resistance to the immunity generated by the current vaccines to prevent coronavirus disease 2019 (Covid-19). Moreover, if some variants of concern have increased transmissibility or virulence, the importance of efficient public health measures and vaccination programs will increase. The global response must be both timely and science based.
Project description:The SARS-CoV-2 global pandemic has seen rapid spread, disease morbidities and death associated with substantive social, economic and societal impacts. Treatments rely on re-purposed antivirals and immune modulatory agents focusing on attenuating the acute respiratory distress syndrome. No curative therapies exist. Vaccines remain the best hope for disease control and the principal global effort to end the pandemic. Herein, we summarize those developments with a focus on the role played by nanocarrier delivery.
Project description:SARS-CoV-2, the causal agent of COVID-19, first emerged in late 2019 in China. It has since infected more than 870,000 individuals and caused more than 43,000 deaths globally. Here, we discuss therapeutic and prophylactic interventions for SARS-CoV-2 with a focus on vaccine development and its challenges. Vaccines are being rapidly developed but will likely come too late to affect the first wave of a potential pandemic. Nevertheless, critical lessons can be learned for the development of vaccines against rapidly emerging viruses. Importantly, SARS-CoV-2 vaccines will be essential to reducing morbidity and mortality if the virus establishes itself in the population.
Project description:COVID-19 emerged in late 2019 and has rapidly spread through many countries globally. The causative SARS-CoV-2 virus was not known until recently, and there is little or no natural immunity in human populations. There is an urgent need for vaccines and drugs to combat this new pandemic. In just a few months, huge efforts and resources by government, academia, and industry have been thrown into the race to develop a vaccine. This brief review summarizes and discusses the array of technologies being applied to vaccine development, highlighting the strengths and weaknesses of the various approaches.
Project description:The ongoing COVID-19 pandemic, caused by SARS-CoV-2, is an unprecedented challenge to humanity. Global herd immunity may be necessary before resumption of normal economic and societal activities. Since the beginning of the outbreak, the development of COVID-19 vaccines has proceeded at record speed using nearly all available platforms or strategies to maximize vaccine success. A total of 42 vaccine candidates have now entered clinical trials and encouraging data from several vaccine candidates in phase 1 or 2 clinical trials have been reported. In this review, we examine current COVID-19 vaccine candidates, discuss their strengths and weaknesses, summarize published clinical data and analyze future challenges.
Project description:Vaccines to prevent acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection elicit an immune neutralizing response. Some concerns have been raised regarding the safety of SARS-CoV-2 vaccines, largely based on case-reports of serious thromboembolic events after vaccination. Some mechanisms have been suggested which might explain the adverse cardiovascular reactions to SARS-CoV-2 vaccines. Different vaccine platforms are currently available which include live attenuated vaccines, inactivated vaccines, recombinant protein vaccines, vector vaccines, DNA vaccines and RNA vaccines. Vaccines increase the endogenous synthesis of SARS-CoV-2 Spike proteins from a variety of cells. Once synthetized, the Spike proteins assembled in the cytoplasma migrate to the cell surface and protrude with a native-like conformation. These proteins are recognized by the immune system which rapidly develops an immune response. Such response appears to be quite vigorous in the presence of DNA vaccines which encode viral vectors, as well as in subjects who are immunized because of previous exposure to SARS-CoV-2. The resulting pathological features may resemble those of active coronavirus disease. The free-floating Spike proteins synthetized by cells targeted by vaccine and destroyed by the immune response circulate in the blood and systematically interact with angiotensin converting enzyme 2 (ACE2) receptors expressed by a variety of cells including platelets, thereby promoting ACE2 internalization and degradation. These reactions may ultimately lead to platelet aggregation, thrombosis and inflammation mediated by several mechanisms including platelet ACE2 receptors. Whereas Phase III vaccine trials generally excluded participants with previous immunization, vaccination of huge populations in the real life will inevitably include individuals with preexisting immunity. This might lead to excessively enhanced inflammatory and thrombotic reactions in occasional subjects. Further research is urgently needed in this area.