Practices, Attitudes, and Knowledge Regarding Recombinant Zoster Vaccine Among Family Medicine Residents in Riyadh, Saudi Arabia.

Background The aim of the research is to determine the existing knowledge, perceived practices, and attitudes toward the recombinant Zoster vaccine among family medicine residents (FMR) included in the medical profession. The present study aims to narrow down the identified gap in knowledge and develop vaccinations that will assist the targeted deme to eradicate zoster and the aftermaths that accompany it. Methods This research utilizes a descriptive cross-sectional survey design to assess the knowledge, practices, and attitudes of FMR toward the zoster vaccine in Riyadh, Saudi Arabia. By quantifying data at a specific point in time, this design allows for a detailed examination of the current status across various levels of residency programs. Participants from different institutions are interviewed simultaneously, enabling a thorough study of the targeted population group. The study includes 154 FMR from three different levels (R1, R2, R3) enrolled in residency programs at various institutions in Riyadh, Saudi Arabia. These participants were selected from a group of individuals invited to share their prior knowledge, habits, and beliefs regarding the recombinant Zoster vaccine. The study offers detailed statistical insights into demographics, vaccination attitudes, and knowledge among healthcare professionals. Key findings highlight diverse recommendations for different adult groups, the prevalence of vaccine availability, and the main sources of immunization information. Results The study found diverse recommendations for vaccination among different adult groups, with mean recommendations ranging from 2.50 to 2.94. Nearly all respondents (96.8%) reported having the vaccine available at their place of practice. However, knowledge gaps were evident, particularly concerning vaccination timing and specific requirements, highlighting the need for targeted education and clearer guidelines in vaccination practices among healthcare providers. Conclusion The study highlights the nuanced vaccination recommendations among healthcare professionals, particularly for different adult populations, and the availability of varicella-zoster virus (VZV) vaccines. The reliance on diverse information sources underscores the need for targeted educational efforts to ensure accurate and consistent immunization practices across healthcare settings. Addressing uncertainties and promoting informed decision-making can enhance vaccination uptake and patient care outcomes in clinical practice.

Varicella Vaccine: a Molecular Variant That May Contribute to Attenuation.

Varicella was troublesome when varicella vaccine (vOka) was licensed in the United States. Varicella's yearly death toll was ~100, indirect costs were massive, and varicella threatened immunocompromised children. Since licensure, varicella has almost disappeared; nevertheless, vOka attenuation has lacked a molecular explanation. Sadaoka et al. (T. Sadaoka, D. P. Depledge, L. Rajbhandari, J. Breuer, et al., mBio 13:e0186422, 2022, https://doi.org/10.1128/mbio.01864-22), however, have now identified 6 core single nucleotide polymorphisms (SNPs), which singly or in combination may contribute to VOka attenuation; moreover, they found a predominant variant allele of vOka encoding the viral glycoprotein gB that results in glutamine instead of arginine at amino acid 699. This change impairs fusion activity and the ability of varicella-zoster virus (VZV) to infect human neurons from axon terminals. Molecular virological studies of vOka are reassuring in suggesting that reversion to virulence is unlikely and should also help assuage current fears about VZV vaccination and alleviate unanticipated future problems. The impressive work of Sadaoka et al. thus represents an auspicious advance in knowledge.

Relative efficacy of varicella vaccines: network meta-analysis of randomized controlled trials.

OBJECTIVE: Although varicella vaccination is highly effective, no head-to-head randomized controlled trials (RCTs) have compared the efficacy of different vaccine formulations. This study assessed the relative efficacy of different varicella vaccines using network meta-analysis (NMA). METHODS: We estimated the relative efficacies of varicella vaccines and dosing regimens from RCTs using Bayesian NMA. Modeling-based time-series NMA (MBNMA) was performed, accounting for differences in time since vaccination, to extrapolate long-term vaccine efficacy (VE). RESULTS: Eight RCTs were included based on systematic review of biomedical databases. Efficacy data were reported for four varicella-containing vaccines: Varivax (V-MSD, one and two dose), Varilrix (V-GSK, one dose), Priorix-Tetra (MMRV-GSK, one dose), and Sinovac (V-Sinovac, one dose). All varicella vaccines were effective versus no vaccination. Two-dose V-MSD (98.29%, 95% credible interval [CrI] 96.08-99.23) showed significantly higher VE versus all one-dose varicella-containing vaccines, but no significant difference versus two-dose MMRV-GSK (95.19%, 95% CrI 90.3-97.63). Two-dose MMRV-GSK showed higher VE than one-dose V-GSK (66.47%; 95% CrI 43.02-79.43), but no significant differences in VE versus one-dose V-MSD or one-dose V-Sinovac. In one-dose comparisons, V-MSD showed significantly higher VE (93.09%, 95% CrI 89.13-95.96) than V-GSK, but no significant difference versus V-Sinovac (89.22%; 95% CrI 67.1-96.5). MBNMA indicated that protection against varicella was sustained without waning over the 10 year follow-up. CONCLUSIONS: Our study reported higher VE for two-dose V-MSD and MMRV-GSK. Among one-dose formulations, one-dose V-MSD was more efficacious than one-dose V-GSK. Policymakers should take into consideration differences in VE when implementing one- versus two-dose strategies in universal vaccination programs.

Persistence of Varicella-Zoster Virus-Specific Plasma Cells in Adult Human Bone Marrow following Childhood Vaccination.

Childhood immunization with the live-attenuated varicella-zoster virus (VZV) vaccine induces protective immune responses. Routine VZV vaccination started only 2 decades ago, and thus, there are few studies examining the longevity of vaccine-induced immunity. Here, we analyzed the quantity of VZV-specific plasma cells (PCs) and CD4 T cells in the bone marrow (BM) of healthy young adults (n = 15) following childhood VZV immunization. Long-lived BM resident plasma cells constitutively secrete antibodies, and we detected VZV-specific PCs in the BM of all subjects. Anti-VZV plasma antibody titers correlated positively with the number of VZV-specific BM PCs. Furthermore, we quantified the number of interferon gamma (IFN-γ)-producing CD4 T cells specific for VZV glycoprotein E and all other structural and nonstructural VZV proteins in both BM and blood (peripheral blood mononuclear cells [PBMCs]). The frequency of VZV-specific IFN-γ-producing CD4 T cells was significantly higher in PBMCs than BM. Our study shows that VZV-specific PCs and VZV-specific CD4 memory T cells persist up to 20 years after vaccination. These findings indicate that childhood VZV vaccination can elicit long-lived immune memory responses in the bone marrow.IMPORTANCE Childhood varicella-zoster virus (VZV) immunization induces immune memory responses that protect against primary VZV infection, chicken pox. In the United States, routine childhood VZV vaccination was introduced only 2 decades ago. Hence, there is limited information on the longevity of B and CD4 T cell memory, which are both important for protection. Here, we showed in 15 healthy young adults that VZV-specific B and CD4 T cell responses are detectable in bone marrow (BM) and blood up to 20 years after vaccination. Specifically, we measured antibody-secreting plasma cells in the BM and VZV-specific CD4 T cells in BM and blood. These findings suggest that childhood VZV vaccination induces long-lived immunity.