ABSTRACT
Adenovirus vectors have been employed to develop a vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for curtailing the Covid-19 pandemic spreading. Many different viral vectors have been mainly targeting the SARS-CoV-2 spike (S) protein as an antigen. Spike (S) protein is comprised of S1 and S2 subunits, in which the receptor-binding domain (RBD) of S1 is responsible for recognizing and engaging with its host cellular receptor protein angiotensin-converting enzyme 2 (ACE2), S2 accounts for membrane fusion of virus and host cell. Chimpanzee adenovirus was also used as a vector vaccine for SARS-CoV-2 (ChAdSARS-CoV-2-S) by intramuscular injection, and intranasal administration has been tested. Adenovirus vector-based vaccines are the most advanced, with several vaccines receiving Emergency Use Authorization (EUA). It was shown that rhesus macaques were protected from SARS-CoV-2 challenge after a month of being vaccinated with ChAd-SARS-CoV-2-S. A single intranasal or two intramuscular ChAd-SARSCoV-2-S vaccines could induce humoral antibodies and T cell responses to protect the upper and lower respiratory tract against SARS-CoV-2. As the effectiveness was demonstrated in non-human primates, ChAd-SARS-CoV-2-Sa potential option for preventing SARS-CoV-2 infection in humans. However, detecting novel more transmissible and pathogenic SARS-CoV-2 variants added concerns about the vaccine efficacy and needs monitoring. Moreover, the cause of recently documented rare cases of vaccine indicated immune thrombotic thrombocytopenia. This review article provided details for the adenovirus vector vaccine for SARS-CoV-2 in humans and tried to provide solutions to the adenovirus vector hemagglutinin issueCopyright © 2023, World's Veterinary Journal.All Rights Reserved.
ABSTRACT
Background and aim: Access to liver transplantation (LT) can beaffected by several barriers resulting in delayed referral and increased risk of mortality. Therefore, hub-and-spoke networks have been implemented in order to manage patients with liver disease. COVID-19 pandemic may have significantly changed this scenario, as most of medical resources have been allocated for the care of patients with SARS-CoV-2 infection. This study aimed to assess the influence of COVID-19 pandemic on referrals of patients with liver disease to a LT Center.Materials and methods: An integrated referral program was developed since 10.2017 at Multivisceral Transplant Unit, PadovaUniversity. All consecutive adult patients with liver disease referred for the first time using this program from 10.2017 to 12.2020 were prospectively collected. Clinical characteristics were analyzedoverall and according to era of referral (pre-COVID-19 era:10.2017-02.2020;COVID-19 era:03.2020-12.2020).Results: 231 patients with liver disease were referred over the study period (men 61%, mean ± SD age: 54±10 years). End-stage liver disease was the most common underlying condition (78.3%), followed by acute liver injury/acute liver failure (17.3%). During COVID-19 pandemic, the rate of referred patients showed a stable trend, if compared with the previous period (5.1 patients/monthvs. 6.1 patients/month), also when only in-patient referrals wereconsidered (pre-COVID-19 era vs.COVID-19 era: 2.9 vs. 3.2 patients/month). Considering 181 patients with cirrhosis, underlying etiology (p=0.22), severity of liver disease (MELD score: 21±7 vs. 20±8;p=0.44), and inpatient referrals (42% vs. 51%;p=0.34) did not differ between pre-COVID-19 and COVID-19 eras. There was a decreasing rate of ICU admission for cirrhosis-related complicationsduring COVID-19 pandemic (22% vs. 34%;p=0.3), with an increased in-hospital transplant-free mortality (41% vs. 30%;p=0.3).Conclusions: Conclusion: Our results did not show a significant decrease in the number of referrals and type of indications during the COVID-19 pandemic;however, the in-hospital transplant free mortality showed an increasing trend, which could be the consequence of a decreasing rate of ICU admissions. Taken together, thesefactors confirmed the importance of a referral network for the care of patients with liver disease, but also how the COVID-19 pandemic may influence the short-term outcome of patients with liver disease.