Deletion of fifteen open reading frames from modified vaccinia virus Ankara fails to improve immunogenicity

Modified vaccinia virus Ankara (MVA) is a highly attenuated strain of vaccinia virus, which has been used as a recombinant vaccine vector in many vaccine development programmes. The loss of many immunosuppressive and host-range genes resulted in a safe and immunogenic vaccine vector. However it still retains some immunomodulatory genes that may reduce MVA immunogenicity. Earlier reports demonstrated that the deletion of the A41L, B15R, C6L, or C12L open reading frames (ORFs) enhanced cellular immune responses in recombinant MVA (rMVA) by up to 2-fold. However, previously, we showed that deletion of the C12L, A44L, A46R, B7R, or B15R ORFs from rMVA, using MVA-BAC recombineering technology, did not enhance rMVA immunogenicity at either peak or memory cellular immune responses. Here, we extend our previous study to examine the effect of deleting clusters of genes on rMVA cellular immunogenicity. Two clusters of fifteen genes were deleted in one rMVA mutant that encodes either the 85A antigen of Mycobacterium tuberculosis or an immunodominant H2-Kd-restricted murine malaria epitope (pb9). The deletion mutants were tested in prime only or prime and boost vaccination regimens. The responses showed no improved peak or memory CD8+ T cell frequencies. Our results suggest that the reported small increases in MVA deletion mutants could not be replicated with different antigens, or epitopes. Therefore, the gene deletion strategy may not be taken as a generic approach for improving the immunogenicity of MVA-based vaccines, and should be carefully assessed for every individual recombinant antigen

Deletion of fifteen open reading frames from modified vaccinia virus Ankara fails to improve immunogenicity

Modified vaccinia virus Ankara (MVA) is a highly attenuated strain of vaccinia virus, which has been used as a recombinant vaccine vector in many vaccine development programmes. The loss of many immunosuppressive and host-range genes resulted in a safe and immunogenic vaccine vector. However it still retains some immunomodulatory genes that may reduce MVA immunogenicity. Earlier reports demonstrated that the deletion of the A41L, B15R, C6L, or C12L open reading frames (ORFs) enhanced cellular immune responses in recombinant MVA (rMVA) by up to 2-fold. However, previously, we showed that deletion of the C12L, A44L, A46R, B7R, or B15R ORFs from rMVA, using MVA-BAC recombineering technology, did not enhance rMVA immunogenicity at either peak or memory cellular immune responses. Here, we extend our previous study to examine the effect of deleting clusters of genes on rMVA cellular immunogenicity. Two clusters of fifteen genes were deleted in one rMVA mutant that encodes either the 85A antigen of Mycobacterium tuberculosis or an immunodominant H2-Kd-restricted murine malaria epitope (pb9). The deletion mutants were tested in prime only or prime and boost vaccination regimens. The responses showed no improved peak or memory CD8+ T cell frequencies. Our results suggest that the reported small increases in MVA deletion mutants could not be replicated with different antigens, or epitopes. Therefore, the gene deletion strategy may not be taken as a generic approach for improving the immunogenicity of MVA-based vaccines, and should be carefully assessed for every individual recombinant antigen

A Cross-Sectional Analysis into the Willingness and Hesitancy to Test and Vaccinate Against COVID-19 Among the Elderly Population in the Kingdom of Saudi Arabia

Reem S AlOmar,1 Nouf A AlShamlan,1 Marwa Mahmoud Shafey,1 Assim M AlAbdulKader,1 Khalid S AlHarkan,1 Wejdan M Al-Johani,1 Sameerah Motabgani,1 Nourah K Alkaltham,1 Abdullah A Alharbi2 1Department of Family and Community Medicine, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia; 2Family and Community Medicine Department, Faculty of Medicine, Jazan University, Jazan City, Jazan, Saudi ArabiaCorrespondence: Reem S AlOmar, Email [email protected]: COVID-19 remains a public health concern. Vaccinations, testing and tracing have been proven to provide strong protection against severe illness and death. Older adults are amongst the groups with an increased risk of severe illness. This study aimed to explore the willingness and hesitancy of the elderly population in the Kingdom of Saudi Arabia to test and vaccinate against COVID-19.Methods: This cross-sectional study targeted participants aged 65 years and above. The questionnaire included both sociodemographic variables, and variables related to willingness and hesitancy to vaccinate and test for COVID-19 that were mainly based on existing literature. Bivariate analyses were performed to test for associations. Significance was set at the 0.05 level.Results: The total sample of respondents was 502. The results show that 52.4% were not aware of a previous infection. Participants aged above 70 years and females were found to be more aware of a previous infection (51.6% and 53.1% respectively) (P < 0.05). Also, 54.7% felt it necessary to test against COVID-19, and among those, 70.8% believed that testing would contain and control the spread. The results also show that 3.2% were not vaccinated to date, compared to 95.41% who had the complete dose as well as the recommended booster dose for elderlies. Age, sex and level of education were significantly associated with vaccine uptake, where participants aged between 65 and 70 years, males and high levels of education were associated with a complete vaccine uptake.Discussion: The current findings add to the epidemiological evidence and show that the social network theory within the context of health may have played a role in self-awareness of previous infections. Also, social factors should be incorporated in public health interventions and public health campaigns targeting the elderly are still needed especially with the continued discovery of variants of interests.Keywords: COVID-19, public health, health promotion, prevention, elderl

Enhancing cellular immunogenicity of MVA-vectored vaccines by utilizing the F11L endogenous promoter

Modified vaccinia virus Ankara (MVA)-vectored vaccines against malaria, influenza, tuberculosis and recently Ebola virus are in clinical development. Although this vector is safe and immunogenic in humans, efforts remain on-going to enhance immunogenicity through various approaches such as using stronger promoters to boost transgene expression. We previously reported that endogenous MVA promoters such as pB8 and pF11 increased transgene expression and immunogenicity, as compared to the conventional p7.5 promoter. Here, we show that both promoters also rivalled the mH5 promoter in enhancing MVA immunogenicity. We investigated the mechanisms behind this improved immunogenicity and show that it was a result of strong early transgene expression in vivo, rather than in vitro as would normally be assessed. Moreover, keeping the TK gene intact resulted in a modest improvement in immunogenicity. Utilizing pB8 or pF11 as ectopic promoters at the TK locus instead of their natural loci also increased transgene expression and immunogenicity. In addition to a reporter antigen, the pF11 promoter was tested with the expression of two vaccine antigens for which cellular immunogenicity was significantly increased as compared to the p7.5 promoter. Our data support the use of the pF11 and pB8 promoters for improved immunogenicity in future MVA-vectored candidate vaccines

Enhancing cellular immunogenicity of MVA-vectored vaccines by utilizing the F11L endogenous promoter

Modified vaccinia virus Ankara (MVA)-vectored vaccines against malaria, influenza, tuberculosis and recently Ebola virus are in clinical development. Although this vector is safe and immunogenic in humans, efforts remain on-going to enhance immunogenicity through various approaches such as using stronger promoters to boost transgene expression. We previously reported that endogenous MVA promoters such as pB8 and pF11 increased transgene expression and immunogenicity, as compared to the conventional p7.5 promoter. Here, we show that both promoters also rivalled the mH5 promoter in enhancing MVA immunogenicity. We investigated the mechanisms behind this improved immunogenicity and show that it was a result of strong early transgene expression in vivo, rather than in vitro as would normally be assessed. Moreover, keeping the TK gene intact resulted in a modest improvement in immunogenicity. Utilizing pB8 or pF11 as ectopic promoters at the TK locus instead of their natural loci also increased transgene expression and immunogenicity. In addition to a reporter antigen, the pF11 promoter was tested with the expression of two vaccine antigens for which cellular immunogenicity was significantly increased as compared to the p7.5 promoter. Our data support the use of the pF11 and pB8 promoters for improved immunogenicity in future MVA-vectored candidate vaccines

COVID-19: Factors associated with psychological distress, fear, and coping strategies among community members across 17 countries

Abstract Background The current pandemic of COVID-19 impacted the psychological wellbeing of populations globally. Objectives We aimed to examine the extent and identify factors associated with psychological distress, fear of COVID-19 and coping. Methods We conducted a cross-sectional study across 17 countries during Jun-2020 to Jan-2021. Levels of psychological distress (Kessler Psychological Distress Scale), fear of COVID-19 (Fear of COVID-19 Scale), and coping (Brief Resilient Coping Scale) were assessed. Results A total of 8,559 people participated; mean age (&plusmn;SD) was 33(&plusmn;13) years, 64% were females and 40% self-identified as frontline workers. More than two-thirds (69%) experienced moderate-to-very high levels of psychological distress, which was 46% in Thailand and 91% in Egypt. A quarter (24%) had high levels of fear of COVID-19, which was as low as 9% in Libya and as high as 38% in Bangladesh. More than half (57%) exhibited medium to high resilient coping; the lowest prevalence (3%) was reported in Australia and the highest (72%) in Syria. Being female (AOR 1.31 [95% CIs 1.09-1.57]), perceived distress due to change of employment status (1.56 [1.29-1.90]), comorbidity with mental health conditions (3.02 [1.20-7.60]) were associated with higher levels of psychological distress and fear. Doctors had higher psychological distress (1.43 [1.04-1.97]), but low levels of fear of COVID-19 (0.55 [0.41-0.76]); nurses had medium to high resilient coping (1.30 [1.03-1.65]). Conclusions The extent of psychological distress, fear of COVID-19 and coping varied by country; however, we identified few higher risk groups who were more vulnerable than others. There is an urgent need to prioritise health and well-being of those people through well-designed intervention that may need to be tailored to meet country specific requirements. </jats:sec