As the latest identified novel severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) variant of concern (VOC), the influence of Omicron on our globe grows promptly. Compared with the last VOC (Delta variant), more mutations were identified, which may address the characteristics of Omicron. Considering these crucial mutations and their implications including an increase in transmissibility, COVID‐19 severity, and reduction of efficacy of currently available diagnostics, vaccines, and therapeutics, Omicron has been classified as one of the VOC. Notably, 15 of these mutations reside in the receptor‐binding domain of spike glycoprotein, which may alter transmissibility, infectivity, neutralizing antibody escape, and vaccine breakthrough cases of COVID‐19. Therefore, our present study characterizes the mutational hotspots of the Omicron variant in comparison with the Delta variant of SARS‐CoV‐2. Furthermore, detailed information was analyzed to characterize the global perspective of Omicron, including transmission dynamic, effect on testing, and immunity, which shall promote the progress of the clinical application and basic research. Collectively, our data suggest that due to continuous variation in the spike glycoprotein sequences, the use of coronavirus‐specific attachment inhibitors may not be the current choice of therapy for emerging SARS‐CoV‐2 VOCs. Hence, we need to proceed with a sense of urgency in this matter.

COVID-19 is the first known pandemic caused by a coronavirus, SARS-CoV-2, which is the third virus in the family Coronaviridae to cause fatal infections in humans after SARS-CoV and MERS-CoV. Animals are involved in the COVID-19 pandemic. This review summarizes the role of animals as reservoirs, natural hosts and experimental models. SARS-CoV-2 originated from animal reservoir, most likely bats and/or pangolins. Anthroponotic transmission has been reported in cats, dogs, tigers, lions and minks. As of now, there is no a strong evidence for natural animal-to-human transmission or sustained animal-to-animal transmission of SARS-CoV-2. Experimental infections conducted by several research groups have shown that monkeys, hamsters, ferrets, cats, tree shrews, transgenic mice and fruit bats were permissive, while dogs, pigs and poultry were resistant. There is an urgent need to understand the zoonotic potential of different viruses in animals, particularly in bats, before they transmit to humans. Vaccines or antivirals against SARS-CoV-2 should be evaluated not only for humans, but also for the protection of companion animals (particularly cats) and susceptible zoo and farm animals.

Background:Vaccination against SARS-CoV-2 is important for reducing hospitalization and mortalities. Both Pfizer-BioNTech (BNT162b2) and the Oxford-AstraZeneca (ChAdOx1 nCoV-19) vaccines are used in Saudi Arabia and in many parts of the world. Post-vaccinal side effects were recorded, so we aimed to screen different complaints after vaccination among vaccinees in Saudi Arabia.Methods:An online questionnaire was designed to screen the local, systemic, and allergic post vaccination reactions for vaccinees who received either one or two doses of the BNT162b2 vaccine or one dose of the ChAdOx1 vaccine. The number and percentage were recorded for each response and analyzed using cross-tab and Chi square tests. The degree of the severity of post vaccination reactions were analyzed using Roc curve. The cofactors that may affect the severity of post-vaccinal reactions including previous COVID-19 infection, age, sex, body mass index, and comorbidities were investigated.Results:During our study, 4,170 individuals reported their responses: 2,601 received one dose of BNT162b2, of whom 456 completed the second dose, and 1,569 received a single dose of ChAdOx1. The side effects were reported in 85.6% of BNT162b2 vaccinees and 96.05% of ChAdOx1 vaccinees who voluntarily responded to a survey about post-vaccination side effects. The side effects were more severe in BNT162b2 than ChAdOx1. ChAdOx1 vaccinees reported mild, moderate, severe and critical side effects in 30.13, 28.62, 29.73, and 1.53%, respectively. In contrast, mild side effects were recorded among the majority of BNT162b2 vaccinees (63.92%) while moderate, severe, and critical side effects were 27.67, 7.68, and 0.72%, respectively. Both local and systemic side effects were recorded more frequently in ChAdOx1 in comparison to BNT162b2 vaccinees. Palpitation was among the new systemic side effects reported in the current study in high frequency. Abnormal menstrual cycle (delaying/increase hemorrhages or pain) was also reported in 0.98% (18/1846) of Pfizer-BioNTech and 0.68% (7/1028) of ChAdOx1 vaccinees, while deep vein thrombosis was only reported in a single case vaccinated with BNT162b2 vaccine.Conclusion:Both vaccines induced post-vaccinal side effects; however, ChAdOx1 induces a higher frequency of post-vaccinal systemic side effects than BNT162b2.

SARS-CoV-2 is a newly emerged coronavirus that causes a respiratory disease with variable severity and fatal consequences. It was first reported in Wuhan and subsequently caused a global pandemic. The viral spike protein binds with the ACE-2 cell surface receptor for entry, while TMPRSS2 triggers its membrane fusion. In addition, RNA dependent RNA polymerase (RdRp), 3′–5′ exoribonuclease (nsp14), viral proteases, N, and M proteins are important in different stages of viral replication. Accordingly, they are attractive targets for different antiviral therapeutic agents. Although many antiviral agents have been used in different clinical trials and included in different treatment protocols, the mode of action against SARS-CoV-2 is still not fully understood. Different potential repurposed drugs, including, chloroquine, hydroxychloroquine, ivermectin, remdesivir, and favipiravir, were screened in the present study. Molecular docking of these drugs with different SARS-CoV-2 target proteins, including spike and membrane proteins, RdRp, nucleoproteins, viral proteases, and nsp14, was performed. Moreover, the binding affinities of the human ACE-2 receptor and TMPRSS2 to the different drugs were evaluated. Molecular dynamics simulation and MM-PBSA calculation were also conducted. Ivermectin and remdesivir were found to be the most promising drugs. Our results suggest that both these drugs utilize different mechanisms at the entry and post-entry stages and could be considered potential inhibitors of SARS-CoV-2 replication.

Infectious bronchitis is highly contagious and constitutes one of the most common and difficult poultry diseases to control. IBV is endemic in probably all countries that raise chickens. It exists as dozens of serotypes/genotypes. Only a few amino acid differences in the S1 protein of vaccine and challenge strains of IBV may result in poor protection. Tropism of IBV includes the respiratory tract tissues, proventriculus and caecal tonsils of the alimentary tract, the oviduct and the kidney. Infectious bronchitis virus (IBV) strain closely related to Massachusetts (Mass) serotype was isolated from broiler chickens suffering from severe renal and respiratory distresses. The isolate was serologically identified by Dot-ELISA and further characterized by RT-PCR then genotyped using S1 gene sequence analysis. Alignment of the S1 sequence of the isolate with 16 IBV strains revealed high homology to isolates related to Mass serotype. Inoculation with the strain reproduced the disease in experimental 1-day-old chickens and resulted in 20% mortality, severe renal and moderate respiratory distresses. Marked histopathological changes in both kidney and trachea were observed in experimentally infected chickens. A protection study using the H120 live attenuated vaccine showed low protection rate in spite of high S1 sequence homology (97%). Protection based criteria were: virus re-isolation attempts from trachea, tracheal and renal histopathology as well as IBV antigens detection by immunofluorescent antibody technique in kidney sections. Periodical evaluation of cross-protective capabilities of IBV vaccine(s) versus recently recovered field isolates should be performed to ensure optimum control of IBV.