Vaccine efficacy against SARS-CoV-2 for Pfizer BioNTech, Moderna, and AstraZeneca vaccines: a systematic review

Impact of vaccination against SARS-CoV-2 on mortality risk, ICU admission rate, and hospitalization length in hospitalized COVID-19 patients: a cross-sectional study

BACKGROUND

Vaccination against SARS-CoV-2 has been crucial in impeding virus spread and preventing fatal complications. Despite growing evidence of vaccine efficacy, data on its impact on hospitalized patients remain limited. We aimed to estimate the risk of mortality, ICU admission, and hospitalization length among hospitalized COVID-19 patients based on vaccination status.

METHODS

In this single-center cross-sectional study, we included patients above 16 years old hospitalized due to COVID-19. Patients were categorized as unvaccinated, partially vaccinated (single dose), or fully vaccinated (at least one booster dose). We performed logistic and linear regression analyses, including both bivariable and multivariable models, to evaluate the association between vaccination status, demographic characteristics, and study outcomes.

RESULTS

Of 299 participants, 21.7%, 15.7%, and 62.5% were unvaccinated, partially vaccinated, and fully vaccinated, respectively. Full vaccination was associated with significantly reduced mortality risk (OR: 0.235, 95%CI: 0.103-0.538) and lower ICU admission rates (OR: 0.252, 95%CI: 0.131-0.484). Vaccinated patients had shorter hospital stays (fully vaccinated: 6.38 ± 1.65 days; unvaccinated: 9.22 ± 2.84 days, p < 0.001). Older age independently predicted higher mortality (OR: 1.062, 95%CI: 1.030-1.095), ICU admission (OR: 1.047, 95%CI: 1.027-1.068), and longer hospital stays (estimate: 0.027, 95%CI: 0.012-0.043). Multiple comorbidities were associated with higher mortality and longer hospitalization (OR: 1.794, 95%CI: 1.244-2.587; estimate: 0.395, 95%CI: 0.142-0.648).

CONCLUSION

Full vaccination against SARS-CoV-2 is associated with significantly improved clinical outcomes in hospitalized COVID-19 patients, including reduced mortality, lower ICU admission rates, and shorter hospital stays.

An Ecological Study Relating the SARS-CoV-2 Epidemiology with Health-Related, Socio-Demographic, and Geographical Characteristics in South Tyrol (Italy)

The literature associating the spread of SARS-CoV-2 with the healthcare-related, geographical, and demographic characteristics of the territory is inconclusive and contrasting. We studied these relationships during winter 2021/2022 in South Tyrol, a multicultural Italian alpine province, performing an ecological study based on the 20 districts of the area. Data about incidence, hospitalization, and death between November 2021 and February 2022 were collected and associated to territorial variables via bivariate analyses and multivariate regressions. Both exposure variables and outcomes varied widely among districts. Incidence was found to be mainly predicted by vaccination coverage (negative correlation). Mortality and ICU admission rates partially followed this distribution, while the case fatality rate was inversely correlated to average salary, and hospital admission rates increased where hospitals capacity was higher, and from the southern to the northern border of the province. These findings, besides confirming the efficacy of vaccination in preventing both new and severe SARS-CoV-2 cases, highlight that several geographical and socio-demographic variables can be related to disease epidemiology. Remote areas with wage gaps and lower access to care suffered most from the pandemic. Our findings, therefore, underly the existence of health inequity issues that need to be targeted by implementing specifically tailored public health interventions.

The Impact of COVID-19 on RNA Therapeutics: A Surge in Lipid Nanoparticles and Alternative Delivery Systems

The COVID-19 pandemic has significantly accelerated progress in RNA-based therapeutics, particularly through the successful development and global rollout of mRNA vaccines. This review delves into the transformative impact of the pandemic on RNA therapeutics, with a strong focus on lipid nanoparticles (LNPs) as a pivotal delivery platform. LNPs have proven to be critical in enhancing the stability, bioavailability, and targeted delivery of mRNA, facilitating the unprecedented success of vaccines like those developed by Pfizer-BioNTech and Moderna. Beyond vaccines, LNP technology is being explored for broader therapeutic applications, including treatments for cancer, rare genetic disorders, and infectious diseases. This review also discusses emerging RNA delivery systems, such as polymeric nanoparticles and viral vectors, which offer alternative strategies to overcome existing challenges related to stability, immune responses, and tissue-specific targeting. Additionally, we examine the pandemic's influence on regulatory processes, including the fast-tracked approvals for RNA therapies, and the surge in research funding that has spurred further innovation in the field. Public acceptance of RNA-based treatments has also grown, laying the groundwork for future developments in personalized medicine. By providing an in-depth analysis of these advancements, this review highlights the long-term impact of COVID-19 on the evolution of RNA therapeutics and the future of precision drug delivery technologies.

Encapsulation of Dexamethasone into mRNA-Lipid Nanoparticles Is a Promising Approach for the Development of Liver-Targeted Anti-Inflammatory Therapies

The objective of this study was to develop two lipid nanoparticle (LNP) formulations capable of efficiently expressing a reporter mRNA while co-delivering the anti-inflammatory drug dexamethasone (DX) to reduce inflammatory side effects in protein replacement therapies. Two types of LNPs were developed, in which 25% of cholesterol was replaced by DX. These LNPs contained either 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) or 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) as a helper lipid. The resulting LNPs exhibited high stability, homogeneity, and near-neutral Zeta potentials. SAXS experiments confirmed DX incorporation into the LNP core, with slow in vitro DX release observed over 48 h. The LNPs achieved high mRNA encapsulation efficiency (95-100%) and effectively transfected HepG2 cells, dendritic cells, and hPBMCs. While LNPs increased cytokine release (IL-1β, TNF-α, MCP-1), LNPs-DX significantly reduced cytokine levels, demonstrating enhanced anti-inflammatory properties while maintaining mRNA expression levels. In vivo biodistribution showed predominant liver localization post-intramuscular injection, regardless of the DSPC or DOPE composition. LNPs co-loaded with mRNA and DX are promising candidates for continuous protein replacement. Due to their ability to reduce treatment-related inflammation while maintaining significant mRNA expression levels, these LNPs are perfectly suited for the treatment of liver-related metabolic diseases.

Frequency of SARS-CoV-2 Infections among Healthcare Workers in Germany: 3-Year Follow-Up Study

The emergence of SARS-CoV-2 in 2019 led to a global pandemic with a significant impact on healthcare systems. Healthcare workers were particularly vulnerable due to frequent contact with COVID-19 patients. Despite vaccination, they remained at higher risk as the vaccines provided limited protection against infection with viral variants, like Delta or Omicron BA.1 and BA.5. Three years after the onset of the pandemic, we evaluated SARS-CoV-2 infection frequencies among healthcare workers with varying levels of patient contact: high-risk (frequent COVID-19 patient contact), intermediate-risk (non-COVID-19 patient contact), and low-risk (no patient contact). We assessed their cellular and humoral immune responses based on their vaccination status and number of prior infections. SARS-CoV-2-specific antibodies were measured by immunoglobulin ELISA, and neutralizing antibody titers were determined against the viral variants D614G, Delta, and Omicron BA.1 and BA.5. Cellular immune responses were analyzed using an interferon-γ ELISpot. Notably, three years into the pandemic, healthcare workers in daily contact with COVID-19 patients did not have higher infection rates compared to healthcare workers with non-COVID-19 patient contact or no patient contact. Immune responses were similar across all groups, highlighting the effectiveness of vaccination and current hygiene standards in preventing virus transmission from patients to staff.

SARS-CoV-2 evolution has increased resistance to monoclonal antibodies and first-generation COVID-19 vaccines: Is there a future therapeutic role for soluble ACE2 receptors for COVID-19?

COVID-19 has caused calamitous health, economic and societal consequences. Although several COVID-19 vaccines have received full authorization for use, global deployment has faced political, financial and logistical challenges. The efficacy of first-generation COVID-19 vaccines is waning and breakthrough infections are allowing ongoing transmission and evolution of SARS-CoV-2. Furthermore, COVID-19 vaccine efficacy relies on a functional immune system. Despite receiving three primary doses and three or more heterologous boosters, some immunocompromised patients may not be adequately protected by COVID-19 vaccines and remain vulnerable to severe disease. The evolution of new SARS-CoV-2 variants has also resulted in the rapid obsolescence of monoclonal antibodies. Convalescent plasma from COVID-19 survivors has produced inconsistent results. New drugs such as Paxlovid (nirmatrelvir/ritonavir) are beyond the reach of low- and middle-income countries. With widespread use of Paxlovid, it is likely nirmatrelvir-resistant clades of SARS-CoV-2 will emerge in the future. There is thus an urgent need for new effective anti-SARS-CoV-2 treatments. The in vitro efficacy of soluble ACE2 against multiple SARS-CoV-2 variants including omicron (B.1.1.529), was recently described using a competitive ELISA assay as a surrogate marker for virus neutralization. This indicates soluble wild-type ACE2 receptors are likely to be resistant to viral evolution. Nasal and inhaled treatment with soluble ACE2 receptors has abrogated severe disease in animal models of COVID-19. There is an urgent need for clinical trials of this new class of antiviral therapeutics, which could complement vaccines and Paxlovid.

Optimizing mRNA-Loaded Lipid Nanoparticles as a Potential Tool for Protein-Replacement Therapy

Lipid nanoparticles (LNPs) tailored for mRNA delivery were optimized to serve as a platform for treating metabolic diseases. Four distinct lipid mixes (LMs) were formulated by modifying various components: LM1 (ALC-0315/DSPC/Cholesterol/ALC-0159), LM2 (ALC-0315/DOPE/Cholesterol/ALC-0159), LM3 (ALC-0315/DSPC/Cholesterol/DMG-PEG2k), and LM4 (DLin-MC3-DMA/DSPC/Cholesterol/ALC-0159). LNPs exhibited stability and homogeneity with a mean size of 75 to 90 nm, confirmed by cryo-TEM and SAXS studies. High mRNA encapsulation (95-100%) was achieved. LNPs effectively delivered EGFP-encoding mRNA to HepG2 and DC2.4 cell lines. LNPs induced cytokine secretion from human peripheral blood mononuclear cells (PBMCs), revealing that LM1, LM2, and LM4 induced 1.5- to 4-fold increases in IL-8, TNF-α, and MCP-1 levels, while LM3 showed minimal changes. Reporter mRNA expression was observed in LNP-treated PBMCs. Hemotoxicity studies confirmed formulation biocompatibility with values below 2%. In vivo biodistribution in mice post intramuscular injection showed significant mRNA expression, mainly in the liver. The modification of LNP components influenced reactogenicity, inflammatory response, and mRNA expression, offering a promising platform for selecting less reactogenic carriers suitable for repetitive dosing in metabolic disease treatment.

In Silico and In Vitro Evaluation of the Molecular Mimicry of the SARS-CoV-2 Spike Protein by Common Short Constituent Sequences (cSCSs) in the Human Proteome: Toward Safer Epitope Design for Vaccine Development

Spike protein sequences in SARS-CoV-2 have been employed for vaccine epitopes, but many short constituent sequences (SCSs) in the spike protein are present in the human proteome, suggesting that some anti-spike antibodies induced by infection or vaccination may be autoantibodies against human proteins. To evaluate this possibility of "molecular mimicry" in silico and in vitro, we exhaustively identified common SCSs (cSCSs) found both in spike and human proteins bioinformatically. The commonality of SCSs between the two systems seemed to be coincidental, and only some cSCSs were likely to be relevant to potential self-epitopes based on three-dimensional information. Among three antibodies raised against cSCS-containing spike peptides, only the antibody against EPLDVL showed high affinity for the spike protein and reacted with an EPLDVL-containing peptide from the human unc-80 homolog protein. Western blot analysis revealed that this antibody also reacted with several human proteins expressed mainly in the small intestine, ovary, and stomach. Taken together, these results showed that most cSCSs are likely incapable of inducing autoantibodies but that at least EPLDVL functions as a self-epitope, suggesting a serious possibility of infection-induced or vaccine-induced autoantibodies in humans. High-risk cSCSs, including EPLDVL, should be excluded from vaccine epitopes to prevent potential autoimmune disorders.

Effectiveness of the SARS-CoV-2 Vaccination in Preventing Severe Disease-Related Outcomes: A Population-Based Study in the Italian Province of Bolzano (South Tyrol)

Objective: To investigate the effectiveness of SARS-CoV2 vaccination in preventing ordinary or intensive care unit (ICU) admissions and deaths among cases registered during a variant transitional pandemic phase in the geographically and culturally unique territory of the Province of Bolzano (South Tyrol), an Italian region with low vaccination coverage. Methods: We collected data from 93,643 patients registered as positive for SARS-CoV-2 by health authorities during the winter of 2021-22. The data were analyzed retrospectively using descriptive statistics and multiple logistic regression. Results: 925 patients were hospitalized (0.99%), 89 (0.10%) were in intensive care, and 194 (0.21%) died. Vaccinated patients had a significantly lower risk of being hospitalized: adjusted Odds Ratio (aOR): 0.39; 95% CI: 0.33-0.46, ICU admission: aOR: 0.16; 95% CI: 0.09-0.29 and death: aOR: 0.41; 95% CI: 0.29-0.58. Similar risk reductions were also observed in booster-vaccinated patients, independent of sex, age, and predominant variant. Furthermore, the median length of stay (LoS) in the ICU was significantly longer for unvaccinated individuals compared to vaccinated subjects (9 vs. 6 days; p < 0.003). Conclusion: Primary series vaccination and ongoing campaign booster doses were effective in preventing all severe disease-related outcomes and in reducing ICU Length of Stay, even during a transitional pandemic phase and in a unique territorial context.