A systematic review of Vaccine Breakthrough Infections by SARS-CoV-2 Delta Variant

Disease Severity in Vaccinated Adults Hospitalized with Breakthrough COVID-19

Background: Vaccination against SARS-CoV-2 is widely used and confers protection against morbidity and mortality in COVID-19. Little is known about disease severity and outcomes in fully vaccinated patients during hospitalization for COVID-19. Aim: To determine whether vaccination status and time from vaccination-to-hospitalization impacted disease severity in patients admitted with COVID-19. Methods: A multicenter retrospective cohort study was conducted on hospitalized adults with COVID-19 between January 1 and September 8, 2021, in Rhode Island, USA. Vaccination status and markers of disease severity, including C-reactive protein, D-Dimer values, and supplemental oxygen use during hospitalization, were obtained. Results: Two thousand three hundred forty-four patients were included. For every vaccinated patient, three unvaccinated patients were matched for a total of 424 patients in the analytic sample. Vaccinated patients had lower peak C-reactive protein (beta = -39.10, 95% CI [-79.10, -0. 65]) and supplemental oxygen requirements (beta = -38.14, 95% CI [-61.62, -9.91]) compared to unvaccinated patients. Patients who had a greater discrepancy between date of vaccination and admission had higher C-reactive protein (beta = 0.37, 95% CI [0.02, 0.71]) and supplemental oxygen requirements (beta = 0.44, 95% CI [0.15, 0.75]. Conclusion: Vaccination against SARS-CoV-2 was associated with a protective effect on disease severity during hospitalization for breakthrough COVID-19. Time elapsed since vaccination was associated with indicators of greater disease severity suggestive of waning protection over time.

Antibody Titers and the Risk of Infection During the SARS-CoV-2 Omicron Phase in Bizen City, Japan

BACKGROUND

Understanding the association between the immune response and the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has implications for forthcoming prevention strategies. We evaluated the association between antibody titers and the risk of infection for the general population during the Omicron-dominant phase.

METHODS

This was a prospective cohort study of residents or people affiliated with institutions in Bizen City, which included 1899 participants. We measured the titers of antibodies against SARS-CoV-2 repeatedly every 2 months from June 2022 to March 2023. Infection status was obtained from self-reported questionnaires and the official registry. We estimated risk ratios (RRs) for infection within 2 months of the date of each antibody measurement with 95% confidence intervals (CIs) based on antibody titer categories and spline functions.

RESULTS

Compared with the <2500 arbitrary unit (AU)/mL category, the 2500-5000, 5000-10 000, and ≥10 000 AU/mL categories had adjusted RRs of 0.81 (95% CI, .61-1.08), 0.51 (95% CI, .36-.72), and 0.41 (95% CI, .31-.54), respectively. The spline function showed a nonlinear relationship between antibody titer and risk.

CONCLUSIONS

Higher antibody titers were associated with a lower risk. We demonstrate the usefulness of measuring an antibody titers to determine the appropriate timing for future prevention strategies.

Kinetics of SARS-CoV-2 antibody titers after booster vaccinations during an Omicron surge in Japan

BACKGROUND

Despite the emergence of SARS-CoV-2 variants and waning immunity after initial vaccination, data on antibody kinetics following booster doses, particularly those adapted to Omicron subvariants like XBB.1.5, remain limited. This study assesses the kinetics of anti-spike protein receptor-binding domain (S-RBD) IgG antibody titers post-booster vaccination in a Japanese population during the Omicron variant epidemic.

METHODS

A prospective cohort study was conducted in Bizen City, Japan, from November 2023 to January 2024. Participants included residents and workers aged ≥18 years, with at least three COVID-19 vaccinations. Antibody levels were measured from venous blood samples. The study analyzed 424 participants and 821 antibody measurements, adjusting for variables such as age, sex, underlying conditions, and prior infection status. Mixed-effects models were employed to describe the kinetics of log-transformed S-RBD antibody titers.

RESULTS

The study found that S-RBD antibody titers declined over time but increased with the number of booster vaccinations, particularly those adapted to Omicron and its subvariant XBB.1.5 (Pfizer-BioNTech Omicron-compatible: 0.156, 95%CI -0.032 to 0.344; Pfizer-BioNTech XBB-compatible: 0.226; 95%CI -0.051 to 0.504; Moderna Omicron-compatible: 0.279, 95%CI 0.012 to 0.546; and Moderna XBB-compatible: 0.338, 95%CI -0.052 to 0.728). Previously infected individuals maintained higher antibody titers, which declined more gradually compared to uninfected individuals (coefficient for interaction with time 0.006; 95%CI 0.001 to 0.011). Sensitivity analyses using Generalized Estimating Equations and interval-censored random intercept model confirmed the robustness of these findings.

CONCLUSIONS

The study provides specific data on antibody kinetics post-booster vaccination, including the XBB.1.5-adapted vaccine, in a highly vaccinated Japanese population. The results highlight the importance of considering individual demographics and prior infection history in optimizing vaccination strategies.

Combining SARS-CoV-2 interferon-gamma release assay with humoral response assessment to define immune memory profiles

OBJECTIVES

In the post-SARS-CoV-2 pandemic era, "breakthrough infections" are still documented, due to variants of concerns (VoCs) emergence and waning humoral immunity. Despite widespread utilization, the definition of the anti-Spike (S) immunoglobulin-G (IgG) threshold to define protection has unveiled several limitations. Here, we explore the advantages of incorporating T-cell response assessment to enhance the definition of immune memory profile.

METHODS

SARS-CoV-2 interferon-gamma release assay test (IGRA) was performed on samples collected longitudinally from immunocompetent healthcare workers throughout their immunization by infection and/or vaccination, anti-receptor-binding domain IgG levels were assessed in parallel. The risk of symptomatic infection according to cellular/humoral immune capacities during Omicron BA.1 wave was then estimated.

RESULTS

Close to 40% of our samples were exclusively IGRA-positive, largely due to time elapsed since their last immunization. This suggests that individuals have sustained long-lasting cellular immunity, while they would have been classified as lacking protective immunity based solely on IgG threshold. Moreover, the Cox regression model highlighted that Omicron BA.1 circulation raises the risk of symptomatic infection while increased anti-receptor-binding domain IgG and IGRA levels tended to reduce it.

CONCLUSION

The discrepancy between humoral and cellular responses highlights the significance of assessing the overall adaptive immune response. This integrated approach allows the identification of vulnerable subjects and can be of interest to guide antiviral prophylaxis at an individual level.

SARS-CoV-2 journey: from alpha variant to omicron and its sub-variants

The COVID-19 pandemic has affected hundreds of millions of individuals and caused more than six million deaths. The prolonged pandemic duration and the continual inter-individual transmissibility have contributed to the emergence of a wide variety of SARS-CoV-2 variants. Genomic surveillance and phylogenetic studies have shown that substantial mutations in crucial supersites of spike glycoprotein modulate the binding affinity of the evolved SARS-COV-2 lineages to ACE2 receptors and modify the binding of spike protein with neutralizing antibodies. The immunological spike mutations have been associated with differential transmissibility, infectivity, and therapeutic efficacy of the vaccines and the immunological therapies among the new variants. This review highlights the diverse genetic mutations assimilated in various SARS-CoV-2 variants. The implications of the acquired mutations related to viral transmission, infectivity, and COVID-19 severity are discussed. This review also addresses the effectiveness of human neutralizing antibodies induced by SARS-CoV-2 infection or immunization and the therapeutic antibodies against the ascended variants.

Factors Associated to Community Practices Toward the COVID-19 Pandemic: A Cross-Sectional Study in Indonesia

Background

COVID-19 still continue to spread and affects most nations globally to date. In this context, community knowledge, attitudes, and practices (KAP) toward COVID-19 are the most important for controlling and preventing the infectious pandemic disease.

Objective

This study aimed to investigate the factors associated with community practices related to COVID-19.

Methods

Cross-sectional study was conducted on 330 residents of Sumedang District, Indonesia. Selection of the sample using stratified random sampling. KAP toward COVID-19 was measured using the WHO questionnaire which is valid and reliable. The data were analyzed using the Rasch model, Pearson correlation, and linear regression.

Results

This study revealed that most respondents tend to answer correctly on the sociality and disease transmission knowledge (+2.08 logit; SE 1.63), incorrectly in conceptual knowledge (logit measure -2.05; SE 0.45), tended to have a positive attitude (+1.6 logit; 0.54) and practice (+1.63 logit; SE 0.61). Based on the results of the Wright map, the most challenging statement for respondents was to use masks. Knowledge and attitude were significantly associated with the practice of COVID-19 prevention (p<0.001). Attitude is the dominant factor influencing society practice towards COVID-19 (Stand. Estimate= 0.2737; 95% CI=0.1608-0.378; p<0.001) and knowledge play an important role in improving COVID-19 prevention behaviour.

Conclusion

New insight from this research shows that even attitude is the most dominant factor, yet this study also indicated that knowledge is critical for positive attitudes of society to support COVID-19 prevention practices. Since, knowledge is the basis for positive attitudes in preventing the transmission of Covid 19. Therefore, health education that explicates concepts, sociality and disease transmission is important to boost attitudes of the society in the practice of Covid 19 prevention.

Unravelling humoral immunity in SARS-CoV-2: Insights from infection and vaccination

Following infection and vaccination against SARS-CoV-2, humoral components of the adaptive immune system play a key role in protecting the host. Specifically, B cells generate high-affinity antibodies against various antigens of the virus. In this review, we discuss the mechanisms of immunity initiation through both natural infection and vaccination, shedding light on the activation of B cell subsets in response to SARS-CoV-2 infection and vaccination. The innate immune system serves as the initial line of primary and nonspecific defence against viruses. However, within several days following infection or a vaccine dose, a virus-specific immune response is initiated, primarily by B cells that produce antibodies. These antibodies contribute to the resolution of the disease. Subsequently, these B cells transition into memory B cells, which play a crucial role in providing long-term immunity against the virus. CD4+ T helper cells initiate a cascade, leading to B cell somatic hypermutation, germinal center memory B cells, and the production of neutralizing antibodies. B-cell dysfunction can worsen disease severity and reduce vaccine efficacy. Notably, individuals with B cell immunodeficiency show lower IL-6 production. Furthermore, this review delves into several aspects of immune responses, such as hybrid immunity, which has shown promise in boosting broad-spectrum protection. Cross-reactive immunity is under scrutiny as well, as pre-existing antibodies can offer protection against the disease. We also decipher breakthrough infection mechanisms, especially with the novel variants of the virus. Finally, we discuss some potential therapeutic solutions regarding B cells including convalescent plasma therapy, B-1 cells, B regulatory cell (Breg) modulation, and the use of neutralizing monoclonal antibodies in combating the infection. Ongoing research is crucial to grasp population immunity trends and assess the potential need for booster doses in maintaining effective immune responses against potential viral threats.

Neutralizing Antibody Levels and Epidemiological Characteristics of Patients with Breakthrough COVID-19 Infection in Toyama, Japan

Breakthrough infection (BI) after coronavirus disease 2019 (COVID-19) vaccination has increased owing to the emergence of novel SARS-CoV-2 variants. In this study, we analyzed the epidemiological information and possession status of neutralizing antibodies in patients with BI using SARS-CoV-2 pseudotyped viruses. Analysis of 44 specimens from patients diagnosed with COVID-19 after two or more vaccinations showed high inhibition of infection by 90% or more against the Wuhan strain and the Alpha and Delta variants of pseudotyped viruses in 40 specimens. In contrast, almost no neutralizing activity was observed against the Omicron BA.1 variant. Many patients without neutralizing activity or BI were immunosuppressed. The results of this study show that contact with an infected person can result in BI, even when there are sufficient neutralizing antibodies in the blood. Thus, sufficient precautions must be taken to prevent infection even after vaccination.

Correlative analysis of wastewater trends with clinical cases and hospitalizations through five dominant variant waves of COVID-19

Wastewater-based epidemiology (WBE) has been utilized to track community infections of Coronavirus Disease 2019 (COVID-19) by detecting RNA of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), within samples collected from wastewater. The correlations between community infections and wastewater measurements of the RNA can potentially change as SARS-CoV-2 evolves into new variations by mutating. This study analyzed SARS-CoV-2 RNA, and indicators of human waste in wastewater from two sewersheds of different scales (University of Miami (UM) campus and Miami-Dade County Central District wastewater treatment plant (CDWWTP)) during five internally defined COVID-19 variant dominant periods (Initial, Pre-Delta, Delta, Omicron and Post-Omicron wave). SARS-CoV-2 RNA quantities were compared against COVID-19 clinical cases and hospitalizations to evaluate correlations with wastewater SARS-CoV-2 RNA. Although correlations between documented clinical cases and hospitalizations were high, prevalence for a given wastewater SARS-CoV-2 level varied depending upon the variant analyzed. The correlative relationship was significantly steeper (more cases per level found in wastewater) for the Omicron-dominated period. For hospitalization, the relationships were steepest for the Initial wave, followed by the Delta wave with flatter slopes during all other waves. Overall results were interpreted in the context of SARS-CoV-2 virulence and vaccination rates among the community.

Molecular and Clinical Epidemiology of SARS-CoV-2 Infection among Vaccinated and Unvaccinated Individuals in a Large Healthcare Organization from New Jersey

New Jersey was among the first states impacted by the COVID-19 pandemic, with one of the highest overall death rates in the nation. Nevertheless, relatively few reports have been published focusing specifically on New Jersey. Here we report on molecular, clinical, and epidemiologic observations, from the largest healthcare network in the state, in a cohort of vaccinated and unvaccinated individuals with laboratory-confirmed SARS-CoV-2 infection. We conducted molecular surveillance of SARS-CoV-2-positive nasopharyngeal swabs collected in nine hospitals from December 2020 through June 2022, using both whole genome sequencing (WGS) and a real-time RT-PCR screening assay targeting spike protein mutations found in variants of concern (VOCs) within our region. De-identified clinical data were obtained retrospectively, including demographics, COVID-19 vaccination status, ICU admission, ventilator support, mortality, and medical history. Statistical analyses were performed to identify associations between SARS-CoV-2 variants, vaccination status, clinical outcomes, and medical risk factors. A total of 5007 SARS-CoV-2-positive nasopharyngeal swabs were successfully screened and/or sequenced. Variant screening identified three predominant VOCs, including Alpha (n = 714), Delta (n = 1877), and Omicron (n = 1802). Omicron isolates were further sub-typed as BA.1 (n = 899), BA.2 (n = 853), or BA.4/BA.5 (n = 50); the remaining 614 isolates were classified as "Other". Approximately 31.5% (1577/5007) of the samples were associated with vaccine breakthrough infections, which increased in frequency following the emergence of Delta and Omicron. Severe clinical outcomes included ICU admission (336/5007 = 6.7%), ventilator support (236/5007 = 4.7%), and mortality (430/5007 = 8.6%), with increasing age being the most significant contributor to each (p < 0.001). Unvaccinated individuals accounted for 79.7% (268/336) of ICU admissions, 78.3% (185/236) of ventilator cases, and 74.4% (320/430) of deaths. Highly significant (p < 0.001) increases in mortality were observed in individuals with cardiovascular disease, hypertension, cancer, diabetes, and hyperlipidemia, but not with obesity, thyroid disease, or respiratory disease. Significant differences (p < 0.001) in clinical outcomes were also noted between SARS-CoV-2 variants, including Delta, Omicron BA.1, and Omicron BA.2. Vaccination was associated with significantly improved clinical outcomes in our study, despite an increase in breakthrough infections associated with waning immunity, greater antigenic variability, or both. Underlying comorbidities contributed significantly to mortality in both vaccinated and unvaccinated individuals, with increasing risk based on the total number of comorbidities. Real-time RT-PCR-based screening facilitated timely identification of predominant variants using a minimal number of spike protein mutations, with faster turnaround time and reduced cost compared to WGS. Continued evolution of SARS-CoV-2 variants will likely require ongoing surveillance for new VOCs, with real-time assessment of clinical impact.

Protection against Severe Illness versus Immunity-Redefining Vaccine Effectiveness in the Aftermath of COVID-19

Anti-SARS-CoV-2 vaccines have played a pivotal role in reducing the risk of developing severe illness from COVID-19, thus helping end the COVID-19 global public health emergency after more than three years. Intriguingly, as SARS-CoV-2 variants emerged, individuals who were fully vaccinated did get infected in high numbers, and viral loads in vaccinated individuals were as high as those in the unvaccinated. However, even with high viral loads, vaccinated individuals were significantly less likely to develop severe illness; this begs the question as to whether the main effect of anti-SARS-CoV-2 vaccines is to confer protection against severe illness or immunity against infection. The answer to this question is consequential, not only to the understanding of how anti-SARS-CoV-2 vaccines work, but also to public health efforts against existing and novel pathogens. In this review, we argue that immune system sensitization-desensitization rather than sterilizing immunity may explain vaccine-mediated protection against severe COVID-19 illness even when the SARS-CoV-2 viral load is high. Through the lessons learned from COVID-19, we make the case that in the disease's aftermath, public health agencies must revisit healthcare policies, including redefining the term "vaccine effectiveness."

The Impact of Vaccination Among Hospitalized Patients with the Diagnosis of COVID-19

Objective

We aimed to investigate the vaccination status and the risk factors for the intensive care unit (ICU) support need of the laboratory-confirmed breakthrough COVID-19 infection inpatients.

Materials and Methods

This multi-center point-prevalence study was conducted on inpatients, divided into two groups as 'fully' and 'partially' vaccinated according to COVID-19 vaccination status.

Results

Totally 516 patients were included in the study. The median age was 65 (55-77), and 53.5% (n=276) of the patients were male. Hypertension (41.9%, n=216), diabetes mellitus (DM) (31.8%, n=164), and coronary artery disease (CAD) (16.3%, n=84) were the predominant comorbidities. Patients were divided into two groups ICU (n=196) and non-ICU (n=301). Hypertension (p=0.026), DM (p=0.048), and congestive heart failure (CHF) (p=0.005) were significantly higher in ICU patients and the median age was younger among non-ICU patients (p=0.033). Of patients, 16.9% (n=87) were fully vaccinated, and this group's need for ICU support was statistically significantly lower (p=0.021).

Conclusion

We conclude that older age, hypertension, DM, CHF, and being partially vaccinated were associated with the need for ICU support. Therefore, all countries should continuously monitor post-vaccination breakthrough COVID-19 infections to determine the national booster vaccine administration approach that will provide vulnerable individuals the highest protection.

Association Between Cycle Threshold Value and Vaccination Status Among Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Cases in Ontario, Canada, in December 2021

Background

Increased immune evasion by emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and occurrence of breakthrough infections raise questions about whether coronavirus disease 2019 vaccination status affects SARS-CoV-2 viral load among those infected. This study examined the relationship between cycle threshold (Ct) value, which is inversely associated with viral load, and vaccination status at the onset of the Omicron wave onset in Ontario, Canada.

Methods

Using linked provincial databases, we compared median Ct values across vaccination status among polymerase chain reaction-confirmed Omicron variant SARS-CoV-2 cases (sublineages B.1.1.529, BA.1, and BA.1.1) between 6 and 30 December 2021. Cases were presumed to be Omicron based on S-gene target failure. We estimated the relationship between vaccination status and Ct values using multiple linear regression, adjusting for age group, sex, and symptom status.

Results

Of the 27 029 presumed Omicron cases in Ontario, the majority were in individuals who had received a complete vaccine series (87.7%), followed by unvaccinated individuals (8.1%), and those who had received a booster dose (4.2%). The median Ct value for post-booster dose individuals (18.3 [interquartile range, 15.4-22.3]) was significantly higher than that for unvaccinated (17.9 [15.2-21.6]; P = .02) and post-vaccine series individuals (17.8 [15.3-21.5]; P = .005). Post-booster dose cases remained associated with a significantly higher median Ct value than cases in unvaccinated individuals (P ≤ .001), after adjustment for covariates. Compared with values in persons aged 18-29 years, Ct values were significantly lower among most age groups >50 years.

Conclusions

While slightly lower Ct values were observed among unvaccinated individuals infected with Omicron compared with post-booster dose cases, further research is required to determine whether a significant difference in secondary transmission exists between these groups.

Urticaria after breakthrough Omicron BA.5.1 severe acute respiratory syndrome coronavirus 2 infection in a triple-vaccinated (Pfizer) patient: a case report

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 continues to threaten public health. The virus is causing breakthrough infections in vaccinated individuals. Also, scarce information is available about cutaneous manifestations after severe acute respiratory syndrome coronavirus 2 infection.

CASE PRESENTATION AND FINDINGS

A case of a triple-vaccinated (Pfizer) 37-year-old Hispanic American (Colombian) male who developed urticaria after Omicron BA.5.1 severe acute respiratory syndrome coronavirus 2 breakthrough infection is described. Virus isolation and whole genome sequencing along with immune and molecular assays were performed. Dermatological manifestations (skin rash and urticaria) after Omicron BA.5.1 infection were observed. Sequence analysis of the Omicron BA.5.1 isolate also revealed several important mutations. Hemogram analysis revealed leukocytosis and neutrophilia. Serology testing revealed anti-spike immunoglobulin G serum titers but negative detection of immunoglobulin M at 10 days after symptom onset. Anti-nucleocapsid, anti-spike 1 immunoglobulin G, anti-spike trimer, and anti-receptor-binding-domain immunoglobulin G and immunoglobulin E sera were detected at different titers 10 days after symptom onset. Several serum levels of chemokines/cytokines (Interferon-α, interferon-γ, interleukin-12/interleukin-23p40, interleukin-18, interferon gamma-induced protein-10, monocyte chemoattractant protein-1, monokine induced by gamma, macrophage inflammatory protein-1α, chemokine (C-C motif) ligand-5 , tumor necrosis factor-β1, Tumor necrosis factor-α) were detected, but interleukin-2, interleukin-4, interleukin-6, interleukin-8, and interleukin-17A were below the limit of detection.

INTERPRETATION AND CONCLUSIONS

To our knowledge, this is the first study describing skin effects of a severe acute respiratory syndrome coronavirus 2 Omicron BA.5 variant breakthrough infection in a triple-vaccinated patient in Colombia. Several important mutations were found in the spike glycoprotein of the virus isolated; these mutations are associated with immune evasion and changes in antigenic properties of the virus. Physicians overseeing coronavirus disease 2019 cases should be aware of the potential skin effects of the infection. Pathogenesis of severe acute respiratory syndrome coronavirus 2 infection and its association with proinflammatory cytokines and chemokines may enhance the development of urticaria and other skin manifestations in immunized individuals. However, further studies are needed to better understand the complexity of coronavirus disease in such situations.

Pulmonary computed tomographic manifestations of COVID-19 in vaccinated and non-vaccinated patients

This study aimed to analyze computed tomographic (CT) imaging features of vaccinated and non-vaccinated COVID-19 patients. The study population of this retrospective single-center cohort study consisted of hospitalized COVID-19 patients who received a chest CT at the study site between July 2021 and February 2022. Qualitative scoring systems (RSNA, CO-RADS, COV-RADS), imaging pattern analysis and semi-quantitative scoring of lung changes were assessed. 105 patients (70,47% male, 62.1 ± 16.79 years, 53.3% fully vaccinated) were included in the data analysis. A significant association between vaccination status and the presence of the crazy-paving pattern was observed in univariate analysis and persisted after step-wise adjustment for possible confounders in multivariate analysis (RR: 2.19, 95% CI: [1.23, 2.62], P = 0.024). Scoring systems for probability assessment of the presence of COVID-19 infection showed a significant correlation with the vaccination status in univariate analysis; however, the associations were attenuated after adjustment for virus variant and stage of infection. Semi-quantitative assessment of lung changes due to COVID-19 infection revealed no association with vaccination status. Non-vaccinated patients showed a two-fold higher probability of the crazy-paving pattern compared to vaccinated patients. COVID-19 variants could have a significant impact on the CT-graphic appearance of COVID-19.

Analysis of the Virus SARS-CoV-2 as a Potential Bioweapon in Light of International Literature

INTRODUCTION

As of early 2022, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic still represents a worldwide medical emergency situation. The ongoing vaccination programs can slow down the spread of the virus; however, from time to time, the newly emerging variants of concern and antivaccination movements carry the possibility for the disease to remain in our daily lives. After the appearance of SARS-CoV-2, there was scholarly debate whether the virus was of natural origin, or it emerged from a laboratory, some even thinking the agent's potential biological weapon properties suggest the latter scenario. Later, the bioweapon theory was dismissed by the majority of experts, but the question remains that despite its natural origin, how potent a biological weapon the SARS-CoV-2 virus can become over time.

MATERIALS AND METHODS

Based on 12 bioweapon threat assessment criteria already published in 2018, we performed a literature search and review, focusing on relevant potential bioweapon properties of the virus SARS-CoV-2. Instead of utilizing a survey among experts, we tried to qualify and quantify characteristics according to the available data found in peer-reviewed papers. We also identified other key elements not mentioned in the original 12 bioweapon criteria, which can play an important role in assessing future biological weapons.

RESULTS

According to the international literature we analyzed, SARS-CoV-2 is a moderately infectious agent (ID50 estimated between 100 and 1,000), with high infection-to-disease ratio (35%-45% rate of asymptomatic infected) and medium incubation period (1-34 days, mean 6-7 days). Its morbidity and mortality rate can be categorized as medium (high morbidity rate with significant mortality rate). It can be easily produced in large quantities, has high aerosol stability, and has moderate environmental stability. Based on laboratory experiments and statistical model analysis, it can form and is contagious with droplet nuclei, and with spray technique utilization, it could be weaponized effectively. Several prophylactic countermeasures are available in the form of vaccines; however, specific therapeutic options are much more limited. In connection with the original assessment criteria, the SARS-CoV-2 only achieved a "0" score on the ease of detection because of readily available, relatively sensitive, and specific rapid antigen tests. Based on the pandemic experience, we also propose three new assessment categories: one that establishes a mean to measure the necessary quarantine restrictions related to a biological agent, another one that can represent the personal protective equipment required to work safely with a particular agent, and a third one that quantifies the overall disruptive capability, based on previous real-life experiences. These factors could further specify the threat level related to potential biological weapons.

CONCLUSIONS

Our results show that the virus can become a potent bioweapon candidate in the future, achieving a total score of 24 out of 36 on the original 12 criteria. The SARS-CoV-2 has already proven its pandemic generating potential and, despite worldwide efforts, still remains an imminent threat. In order to be prepared for the future possibility of the virus arising as a bioweapon, we must remain cautious and take the necessary countermeasures.

Monitoring algorithm of hospitalized patients in a medical center with SARS-CoV-2 (Omicron variant) infection: clinical epidemiological surveillance and immunological assessment

Purpose

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a major healthcare threat worldwide. Since it was first identified in November 2021, the Omicron (B.1.1.529) variant of SARS-CoV-2 has evolved into several lineages, including BA.1, BA.2-BA.4, and BA.5. SARS-CoV-2 variants might increase transmissibility, pathogenicity, and resistance to vaccine-induced immunity. Thus, the epidemiological surveillance of circulating lineages using variant phenotyping is essential. The aim of the current study was to characterize the clinical outcome of Omicron BA.2 infections among hospitalized COVID-19 patients and to perform an immunological assessment of such cases against SARS-CoV-2.

Patients and Methods

We evaluated the analytical and clinical performance of the BioIC SARS-CoV-2 immunoglobulin (Ig)M/IgG detection kit, which was used for detecting antibodies against SARS-CoV-2 in 257 patients infected with the Omicron variant.

Results

Poor prognosis was noted in 38 patients, including eight deaths in patients characterized by comorbidities predisposing them to severe COVID-19. The variant-of-concern (VOC) typing and serological analysis identified time-dependent epidemic trends of BA.2 variants emerging in the outbreak of the fourth wave in Taiwan. Of the 257 specimens analyzed, 108 (42%) and 24 (9.3%) were positive for anti-N IgM and IgG respectively.

Conclusion

The VOC typing of these samples allowed for the identification of epidemic trends by time intervals, including the B.1.1.529 variant replacing the B.1.617.2 variant. Moreover, antibody testing might serve as a complementary method for COVID-19 diagnosis. The combination of serological testing results with the reverse transcription-polymerase chain reaction cycle threshold value has potential value in disease prognosis, thereby aiding in epidemic investigations conducted by clinicians or the healthcare department.

SARS-CoV-2 breakthrough infections during the second wave of COVID-19 at Pune, India

Breakthrough infections following SARS-CoV-2 vaccination remain the global concern. The current study was conducted during the second wave of COVID-19 (1st March-7th July 2021) in Pune, India, at two tertiary care hospitals. Of the 6,159 patients diagnosed as COVID-19, 372/2,210 (16.8%) were breakthrough infections. Of these, 81.1 and 18.8% received one or two doses of Covishield or Covaxin, respectively. Of note, 30.7% patients were with comorbidities, hypertension being the commonest (12.44%). The majority of infections were mild (81.2%). Forty-three patients with breakthrough infections were hospitalized with severe (n = 27, 62.8%) or moderate (n = 16, 37.2%) disease. The receptor binding domain (RBD) sequences from vaccinated (n = 126) and non-vaccinated (n = 168) samples were used for variant analysis. The delta variant was predominant followed by kappa in both vaccinated and non-vaccinated groups. Viral load (qRT-PCR) was not different among these categories. Full-genome comparisons of sequences in relation to vaccination status did not identify any mutation characteristic of the vaccinated group. Irrespective of the number of doses, neutralizing antibody titers (PRNT50) during the first week of clinical disease were higher in the vaccinated patients than the unvaccinated category. In conclusion, though not completely, SARS-CoV-2 vaccines used for country-wide immunization did reduce disease severity among the individuals without any comorbidity by inducing rapid immune response against distinctly different delta and kappa variants. The utility against emerging variants with further mutations need to be carefully examined.

The causal effect of physical activity intensity on COVID-19 susceptibility, hospitalization, and severity: Evidence from a mendelian randomization study

The protection of physical activity (PA) against COVID-19 is a rising research interest. However, the role of physical activity intensity on this topic is yet unclear. To bridge the gap, we performed a Mendelian randomization (MR) study to verify the causal influence of light and moderate-to-vigorous PA on COVID-19 susceptibility, hospitalization, and severity. The Genome-Wide Association Study (GWAS) dataset of PA (n = 88,411) was obtained from the UK biobank and the datasets of COVID-19 susceptibility (n = 1,683,768), hospitalization (n = 1,887,658), and severity (n = 1,161,073) were extracted from the COVID-19 Host Genetics Initiative. A random-effect inverse variance weighted (IVW) model was carried out to estimate the potential causal effects. A Bonferroni correction was used for counteracting. The problem of multiple comparisons. MR-Egger test, MR-PRESSO test, Cochran's Q statistic, and Leave-One-Out (LOO) were used as sensitive analysis tools. Eventually, we found that light PA significantly reduced the risk of COVID-19 infection (OR = 0.644, 95% CI: 0.480-0.864, p = 0.003). Suggestive evidence indicated that light PA reduced the risks of COVID-19 hospitalization (OR = 0.446, 95% CI: 0.227 to 0.879, p = 0.020) and severe complications (OR = 0.406, 95% CI: 0.167-0.446, p = 0.046). By comparison, the effects of moderate-to-vigorous PA on the three COVID-19 outcomes were all non-significant. Generally, our findings may offer evidence for prescribing personalized prevention and treatment programs. Limited by the available datasets and the quality of evidence, further research is warranted to re-examine the effects of light PA on COVID-19 when new GWAS datasets emerge.

Exploring the experience of developing COVID-19 vaccines in Iran

Widespread public vaccination is one of the effective mechanisms to ensure the health and prevent deaths in societies. The coronavirus disease 2019 (COVID-19) vaccine is a stark instance in this regard. Vaccine development is a complex process requiring firm-level capabilities, various infrastructures, long-term planning, and stable and efficient policies. Due to the global demand for vaccines during the pandemic, the national capability to produce vaccines is critical. To this end, the current paper investigates influential factors, at the firm- and policy-level, in the COVID-19 vaccine development process in Iran. By adopting a qualitative research method and conducting 17 semi-structured interviews and analyzing policy documents, news, and reports, we extracted internal and external factors affecting the success and failure of a vaccine development project. We also discuss the characteristics of the vaccine ecosystem and the gradual maturity of policies. This paper draws lessons for vaccine development in developing countries at both firm and policy levels.

Global emerging Omicron variant of SARS-CoV-2: Impacts, challenges and strategies

Newly emerging variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are continuously posing high global public health concerns and panic resulting in waves of coronavirus disease 2019 (COVID-19) pandemic. Depending on the extent of genomic variations, mutations and adaptation, few of the variants gain the ability to spread quickly across many countries, acquire higher virulency and ability to cause severe disease, morbidity and mortality. These variants have been implicated in lessening the efficacy of the current COVID-19 vaccines and immunotherapies resulting in break-through viral infections in vaccinated individuals and recovered patients. Altogether, these could hinder the protective herd immunity to be achieved through the ongoing progressive COVID-19 vaccination. Currently, the only variant of interest of SARS-CoV-2 is Omicron that was first identified in South Africa. In this review, we present the overview on the emerging SARS-CoV-2 variants with a special focus on the Omicron variant, its lineages and hybrid variants. We discuss the hypotheses of the origin, genetic change and underlying molecular mechanism behind higher transmissibility and immune escape of Omicron variant. Major concerns related to Omicron including the efficacy of the current available immunotherapeutics and vaccines, transmissibility, disease severity, and mortality are discussed. In the last part, challenges and strategies to counter Omicron variant, its lineages and hybrid variants amid the ongoing COVID-19 pandemic are presented.

Knowledge, attitudes, and behaviors regarding COVID-19 among hospitalized patients in Taizhou, China

Objection

This study investigated the relationship between the knowledge, attitudes, and behaviors among hospitalized patients regarding the prevention and control of COVID-19.

Method

An online cross-sectional survey was conducted among hospitalized patients between July 8 and August 11, 2021, at a tertiary hospital in Taizhou, China. We performed descriptive analysis, t test, ANOVA (analysis of variance), and generalized linear regression modeling on the exported data. All data were analyzed using R software, version 4.1.0.

Results

A total of 1185 valid questionnaires were returned. The average score of the participants on COVID-19 behaviors was 69.3 (SD = 15.6, with a full score of 87), indicating that most inpatients had good COVID-19 prevention and control behaviors. In addition, we found that inpatients with higher COVID-19 awareness also behaved better (B (95%CI) = 1.00 (0.73-1.27)) and were more willing to recommend vaccination to other people (OR (95%CI) = 1.11 (1.06-1.17)). Moreover, hospitalized patients who had positive attitudes toward implementing COVID-19 prevention and control measures had better practices (B (95%CI) = 2.50 (2.24-2.76)) and more willingness to recommend vaccinations (OR (95%CI) = 1.20 (1.14-1.26)).

Conclusion

The research showed that the COVID-19 behaviors of hospitalized patients were positively associated with their knowledge and attitudes. These findings suggested that, for inpatients, hospitals should focus on teaching basic prevention knowledge of COVID-19. Targeted education initiatives should also be developed for patients from rural areas, especially those over 60 years of age, to help improve their knowledge and cultivate good prevention and control behaviors.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10389-022-01796-y.

The second year of pandemic in the Arctic: examining spatiotemporal dynamics of the COVID-19 "Delta wave" in Arctic regions in 2021

The second year of the COVID-19 pandemic in the Arctic was dominated by the Delta wave that primarily lasted between July and December 2021 with varied epidemiological outcomes. An analysis of the Arctic's subnational COVID-19 data revealed a massive increase in cases and deaths across all its jurisdictions but at varying time periods. However, the case fatality ratio (CFR) in most Arctic regions did not rise dramatically and was below national levels (except in Northern Russia). Based on the spatiotemporal patterns of the Delta outbreak, we identified four types of pandemic waves across Arctic regions: Tsunami (Greenland, Iceland, Faroe Islands, Northern Norway, Northern Finland, and Northern Canada), Superstorm (Alaska), Tidal wave (Northern Russia), and Protracted Wave (Northern Sweden). These regionally varied COVID-19 epidemiological dynamics are likely attributable to the inconsistency in implementing public health prevention measures, geographical isolation, and varying vaccination rates. A lesson remote and Indigenous communities can learn from the Arctic is that the three-prong (delay-prepare-respond) approach could be a tool in curtailing the impact of COVID-19 or future pandemics. This article is motivated by previous research that examined the first and second waves of the pandemic in the Arctic. Data are available at https://arctic.uni.edu/arctic-covid-19.

Progress Update on the Epidemiology of COVID-19 Variants and the Assessment Status of Developed Vaccines

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has spread rapidly and diffused to more than 180 countries at varying severities. This pandemic has accounted for increased mortality and morbidity in developed as well as developing nations. The WHO has announced that there is a persistent need for the evaluation of the COVID-19 vaccine effectiveness (VE) against major outcomes, which include severe diseases, symptomatic COVID-19, and mortalities related to COVID-19. Therefore, mass vaccination programs using vaccines of high effectiveness are among the strategies that have been used by governments worldwide to impede the COVID-19 pandemic transmission. In this regard, massive efforts were made by governments, scientists, biomedical researchers, and healthcare professionals leading to the successful development of various vaccines to bring this pandemic under control. This editorial aims to shed light on the epidemiological status of COVID-19 variants, namely, Delta, Omicron, and Deltacron variants as well as discuss the effectiveness of the currently available COVID-19 vaccines.

Delta variant (B.1.617.2) of SARS-CoV-2: Mutations, impact, challenges and possible solutions

Since commencement of COVID-19 pandemic, several SARS-CoV-2 variants have emerged amid containment efforts via vaccination. The Delta variant (B.1.617.2), discovered in October 2020, was designated as a VOC by the WHO on May 11, 2021. The enhanced transmissibility of Delta variant has been associated with critical mutations such as D614G, L452R, P681R, and T478K in the S-protein. The increased affinity of the S-protein and ACE2 has been postulated as a key reason for decreased vaccine efficacy. As per evidence, the Delta variant possesses increased transmissibility and decreased vaccine efficacy compared to other VOCs like Alpha and Beta. This has led to concerns regarding the acquisition of novel mutations in the Delta variant and outbreaks in vulnerable communities, including vaccinated people. In this mini-review of Delta variant, we have explained its evolution and characteristics, the impact of spike mutations on infectivity and immune evasion, and measures to combat future outbreaks.

COVID-19 vaccination challenges: A mini-review

The emergence of SARS-CoV-2 has led to the infection of many people across the globe, over six million deaths, and has placed an unprecedented burden on public health worldwide. The pandemic has led to the high-speed development and production of vaccines against the COVID-19, as vaccines can end the pandemic. At the beginning of the program, vaccinations were initially targeted only at high-risk groups, such as the elderly, those with comorbidities, or healthcare workers. Although most of the mentioned populations have received the two recommended doses, limited resources have left many authorities with an effective vaccine undersupply. Therefore, policies have been implemented to manage the available doses of the vaccines more efficiently. As there is no universally agreed consensus on this topic, we discuss the different recommendations and guidelines regarding the time interval between the two vaccine doses and explain the different scenarios for applying the two doses.

Possible Application of Melatonin in Long COVID

Clinical sequelae and symptoms for a considerable number of COVID-19 patients can linger for months beyond the acute stage of SARS-CoV-2 infection, "long COVID". Among the long-term consequences of SARS-CoV-2 infection, cognitive issues (especially memory loss or "brain fog"), chronic fatigue, myalgia, and muscular weakness resembling myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are of importance. Melatonin may be particularly effective at reducing the signs and symptoms of SARS-CoV-2 infection due to its functions as an antioxidant, anti-inflammatory, and immuno-modulatory agent. Melatonin is also a chronobiotic medication effective in treating delirium and restoring the circadian imbalance seen in COVID patients in the intensive care unit. Additionally, as a cytoprotector, melatonin aids in the prevention of several COVID-19 comorbidities, including diabetes, metabolic syndrome, and ischemic and non-ischemic cardiovascular diseases. This narrative review discusses the application of melatonin as a neuroprotective agent to control cognitive deterioration ("brain fog") and pain in the ME/CFS syndrome-like documented in long COVID. Further studies on the therapeutic use of melatonin in the neurological sequelae of SARS-CoV-2 infection are warranted.

A systematic review of current status and challenges of vaccinating children against SARS-CoV-2

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has inflicted immense damage to countries, economies and societies worldwide. Authorized COVID-19 vaccines based on different platforms have been widely inoculated in adults, showing up to 100% immunogenicity with significant efficacy in preventing SARS-CoV-2 infections and the occurrence of severe COVID-19. It has also greatly slowed the evolution of SARS-CoV-2 variants, as shown in clinical trials and real-world evidence. However, the total dosage of COVID-19 vaccines for children is much smaller than that for adults due to limitations from parental concern of vaccine safety, presenting a potential obstacle in ending the COVID-19 pandemic. SARS-CoV-2 not only increases the risk of severe multisystem inflammatory syndrome (MIS-C) in children, but also negatively affects children's psychology and academics, indirectly hindering the maintenance and progress of normal social order. Therefore, this article examines the clinical manifestations of children infected with SARS-CoV-2, the status of vaccination against COVID-19 in children, vaccination-related adverse events, and the unique immune mechanisms of children. In particular, the necessity and challenges of vaccinating children against SARS-CoV-2 were highlighted from the perspectives of society and family. In summary, parental hesitancy is unnecessary as adverse events after COVID-19 vaccination have been proven to be infrequent, comprise of mild symptoms, and have a good prognosis.

Clinical-epidemiologic variation in patients treated in the first and second wave of COVID-19 in Lambayeque, Peru: A cluster analysis

OBJECTIVES

To identify differences in the clinical and epidemiologic characteristics of patients during the first and second waves of the COVID-19 pandemic at the EsSalud Lambayeque health care network, Peru.

METHODS

An analytical cross-sectional study of 53,912 patients enrolled during the first and second waves of COVID-19 was conducted. Cluster analysis based on clustering large applications (CLARA) was applied to clinical-epidemiologic data presented at the time of care. The two pandemic waves were compared using clinical-epidemiologic data from epidemiologic surveillance.

RESULTS

Cluster analysis identified four COVID-19 groups with a characteristic pattern. Cluster 1 included the largest number of participants in both waves, and the participants were predominantly female. Cluster 2 included patients with gastrointestinal, respiratory, and systemic symptoms. Cluster 3 was the "severe" cluster, characterized by older adults and patients with dyspnea or comorbidities (cardiovascular, diabetes, obesity). Cluster 4 included asymptomatic, pregnant, and less severe patients. We found differences in all clinical-epidemiologic characteristics according to the cluster to which they belonged.

CONCLUSION

Using cluster analysis, we identified characteristic patterns in each group. Respiratory, gastrointestinal, dyspnea, anosmia, and ageusia symptoms were higher in the second COVID-19 wave than the first COVID-19 wave.

Transmission of SARS-CoV-2 in a primary school setting with and without public health measures using real-world contact data: A modelling study

Background

Stringent public health measures have been shown to influence the transmission of SARS-CoV-2 within school environments. We investigated the potential transmission of SARS-CoV-2 in a primary school setting with and without public health measures, using fine-grained physical positioning traces captured before the COVID-19 pandemic.

Methods

Approximately 172.63 million position data from 98 students and six teachers from an open-plan primary school were used to predict a potential transmission of SARS-CoV-2 in primary school settings. We first estimated the daily average number of contacts of students and teachers with an infected individual during the incubation period. We then used the Reed-Frost model to estimate the probability of transmission per contact for the SARS-CoV-2 Alpha (B.1.1.7), Delta (B.1.617.2), and Omicron variant (B.1.1.529). Finally, we built a binomial distribution model to estimate the probability of onward transmission in schools with and without public health measures, including face masks and physical distancing.

Results

An infectious student would have 49.1 (95% confidence interval (CI) = 46.1-52.1) contacts with their peers and 2.00 (95% CI = 1.82-2.18) contacts with teachers per day. An infectious teacher would have 47.6 (95% CI = 45.1-50.0) contacts with students and 1.70 (95% CI = 1.48-1.92) contacts with their colleague teachers per day. While the probability of onward SARS-CoV-2 transmission was relatively low for the Alpha and Delta variants, the risk increased for the Omicron variant, especially in the absence of public health measures. Onward teacher-to-student transmission (88.9%, 95% CI = 88.6%-89.1%) and teacher-to-teacher SARS-CoV-2 transmission (98.4%, 95% CI = 98.5%-98.6%) were significantly higher for the Omicron variant without public health measures in place.

Conclusions

Our findings illustrate that, despite a lower frequency of close contacts, teacher-to-teacher close contacts demonstrated a higher risk of transmission per contact of SARS-CoV-2 compared to student-to-student close contacts. This was especially significant with the Omicron variant, with onward transmission more likely occurring from teacher index cases than student index cases. Public health measures (eg, face masks and physical distance) seem essential in reducing the risk of onward transmission within school environments.

mRNA Vaccines Against SARS-CoV-2 Variants Delivered by Lipid Nanoparticles Based on Novel Ionizable Lipids

SARS-CoV-2 variants are now still challenging all the approved vaccines, including mRNA vaccines. There is an urgent need to develop new generation mRNA vaccines with more powerful efficacy and better safety against SARS-CoV-2 variants. In this study, a new set of ionizable lipids named 4N4T are constructed and applied to form novel lipid nanoparticles called 4N4T-LNPs. Leading 4N4T-LNPs exhibit much higher mRNA translation efficiency than the approved SM-102-LNPs. To test the effectiveness of the novel delivery system, the DS mRNA encoding the full-length S protein of the SARS-CoV-2 variant is synthesized and loaded in 4N4T-LNPs. The obtained 4N4T-DS mRNA vaccines successfully trigger robust and durable humoral immune responses against SARS-CoV-2 and its variants including Delta and Omicron. Importantly, the novel vaccines have higher RBD-specific IgG titers and neutralizing antibody titers than SM-102-based DS mRNA vaccine. Besides, for the first time, the types of mRNA vaccine-induced neutralizing antibodies are found to be influenced by the chemical structure of ionizable lipids. 4N4T-DS mRNA vaccines also induce strong Th1-skewed T cell responses and have good safety. This work provides a novel vehicle for mRNA delivery that is more effective than the approved LNPs and shows its application in vaccines against SARS-CoV-2 variants.

Household Transmission of SARS-CoV-2 in Bhutan

Introduction

The transmission trend of SARS-CoV-2 is continuously evolving. Understanding the dynamics in different settings is crucial for any effective containment measures. We aimed to study the characteristics of household transmission of SARS-CoV-2 in Bhutanese households by determining the transmissibility within household contacts of confirmed COVID-19 index cases and their factors of infectivity.

Methods

We conducted a retrospective observational study on household transmission in 306 household contacts of 93 COVID-19 positive index cases diagnosed from April 16, 2021, to June 30, 2021. A pro forma was used to collect data on the epidemiological, demographic, and clinical profile of all recruited individuals. Secondary attack rates (SAR) were calculated, and risk factors for transmission were estimated.

Results

180 of 306 household contacts developed secondary household transmission (SAR 58.8%; 95% CI: 53.2-64.2). The median age of household contacts was 22 years. The median household size was 4 (mean 4.3 ± 2.199) members. Contacts exposed to adult index cases (aPR 1; 95% CI 1, 1.02, p = 0.01) and vaccinated index cases (uPR 0.41, 95% CI 0.25, 0.66, p < 0.001) had a higher SAR and prevalence of secondary infections.

Conclusions

Our findings suggest substantial evidence of secondary infections among household contacts, especially in the context of public health mandated lockdowns. Aggressive early contact tracing and case identification with subsequent case isolation from other household members remains a crucial step in preventing secondary transmission.

From HIV to COVID-19, Molecular mechanisms of pathogens' trade-off and persistence in the community, potential targets for new drug development

BACKGROUND

On the staggering emergence of the Omicron variant, numerous questions arose about the evolution of virulence and transmissibility in microbes.

MAIN BODY OF THE ABSTRACT

The trade-off hypothesis has long speculated the exchange of virulence for the sake of superior transmissibility in a wide array of pathogens. While this certainly applies to the case of the Omicron variant, along with influenza virus, various reports have been allocated for an array of pathogens such as human immunodeficiency virus (HIV), malaria, hepatitis B virus (HBV) and tuberculosis (TB). The latter abide to another form of trade-off, the invasion-persistence trade-off. In this study, we aim to explore the molecular mechanisms and mutations of different obligate intracellular pathogens that attenuated their more morbid characters, virulence in acute infections and invasion in chronic infections.

SHORT CONCLUSION

Recognizing the mutations that attenuate the most morbid characters of pathogens such as virulence or persistence can help in tailoring new therapies for such pathogens. Targeting macrophage tropism of HIV by carbohydrate-binding agents, or targeting the TMPRSS2 receptors to prevent pulmonary infiltrates of COVID-19 is an example of how important is to recognize such genetic mechanisms.

Emergence of Omicron BA.1 and BA.2 variants and concern over vaccine breakthrough infection

The COVID-19 pandemic since 2020 created havoc across the globe. This led to the establishment of effective vaccines to mitigate the virus. Several vaccines are developed to create immunity amongst the population. However, due to emerging variants of SARS-CoV-2, despite a double dose of vaccines, people have still infected that termed vaccine breakthrough infection. This paper aims to highlight the recent re-surging massive outbreak of COVID-19 in China despite mass vaccination and, discuss the issue of vaccine breakthrough infection, possible causes, and recommendations to enhance immunity and curb the transmission.

Biological Properties of SARS-CoV-2 Variants: Epidemiological Impact and Clinical Consequences

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a virus that belongs to the coronavirus family and is the cause of coronavirus disease 2019 (COVID-19). As of May 2022, it had caused more than 500 million infections and more than 6 million deaths worldwide. Several vaccines have been produced and tested over the last two years. The SARS-CoV-2 virus, on the other hand, has mutated over time, resulting in genetic variation in the population of circulating variants during the COVID-19 pandemic. It has also shown immune-evading characteristics, suggesting that vaccinations against these variants could be potentially ineffective. The purpose of this review article is to investigate the key variants of concern (VOCs) and mutations of the virus driving the current pandemic, as well as to explore the transmission rates of SARS-CoV-2 VOCs in relation to epidemiological factors and to compare the virus's transmission rate to that of prior coronaviruses. We examined and provided key information on SARS-CoV-2 VOCs in this study, including their transmissibility, infectivity rate, disease severity, affinity for angiotensin-converting enzyme 2 (ACE2) receptors, viral load, reproduction number, vaccination effectiveness, and vaccine breakthrough.

VSV-Based Vaccines Reduce Virus Shedding and Viral Load in Hamsters Infected with SARS-CoV-2 Variants of Concern

The continued progression of the COVID-19 pandemic can partly be attributed to the ability of SARS-CoV-2 to mutate and introduce new viral variants. Some of these variants with the potential to spread quickly and conquer the globe are termed variants of concern (VOC). The existing vaccines implemented on a global scale are based on the ancestral strain, which has resulted in increased numbers of breakthrough infections as these VOC have emerged. It is imperative to show protection against VOC infection with newly developed vaccines. Previously, we evaluated two vesicular stomatitis virus (VSV)-based vaccines expressing the SARS-CoV-2 spike protein alone (VSV-SARS2) or in combination with the Ebola virus glycoprotein (VSV-SARS2-EBOV) and demonstrated their fast-acting potential. Here, we prolonged the time to challenge; we vaccinated hamsters intranasally (IN) or intramuscularly 28 days prior to infection with three SARS-CoV-2 VOC-the Alpha, Beta, and Delta variants. IN vaccination with either the VSV-SARS2 or VSV-SARS2-EBOV resulted in the highest protective efficacy as demonstrated by decreased virus shedding and lung viral load of vaccinated hamsters. Histopathologic analysis of the lungs revealed the least amount of lung damage in the IN-vaccinated animals regardless of the challenge virus. This data demonstrates the ability of a VSV-based vaccine to not only protect from disease caused by SARS-CoV-2 VOC but also reduce viral shedding.

Global trends in COVID-19

The pandemic COVID-19 is certainly one of the most severe infectious diseases in human history. In the last 2 years, the COVID-19 pandemic has caused over 418.6 million confirmed cases and 5.8 million deaths worldwide. Young people make up the majority of all infected COVID-19 cases, but the mortality rate is relatively lower compared to older age groups. Currently, about 55.04% individuals have been fully vaccinated rapidly approaching to herd immunity globally. The challenge is that new SARS-CoV-2 variants with potential to evade immunity from natural infection or vaccine continue to emerge. Breakthrough infections have occurred in both SARS-CoV-2 naturally infected and vaccinated individuals, but breakthrough infections tended to exhibit mild or asymptomatic symptoms and lower mortality rates. Therefore, immunity from natural infection or vaccination can reduce SARS-CoV-2 pathogenicity, but neither can completely prevent SARS-CoV-2 infection/reinfection. Fortunately, the morbidity and mortality of COVID-19 continue to decline. The 7-day average cumulative case fatality of COVID-19 has decreased from 12.3% on the February 25, 2020, to 0.27% on January 09, 2022, which could be related to a decreased SARS-CoV-2 variant virulence, vaccine immunization, and/or better treatment of patients. In conclusion, elimination of SARS-CoV-2 in the world could be impossible or at least an arduous task with a long way to go. The best strategy to prevent COVID-19 pandemic is to expand inoculation rate of effective vaccines. As the population reaches herd immunity, the mortality rate of COVID-19 may continue to decrease, and COVID-19 could eventually become another common cold.

Knowledge, Attitude, and Practice (KAP) toward COVID-19 Pandemic among the Public in Taiwan: A Cross-Sectional Study

Purpose: Knowledge, attitude, and practice (KAP) models are often used by researchers in the field of public health to explore people’s healthy behaviors. Therefore, this study mainly explored the relationships among participants’ sociodemographic status, COVID-19 knowledge, affective attitudes, and preventive behaviors. Method: This study adopted an online survey, involving a total of 136 males and 204 females, and used a cross-sectional study to investigate the relationships between variables including gender, age, COVID-19 knowledge, positive affective attitudes (emotional wellbeing, psychological wellbeing, and social wellbeing), negative affective attitudes (negative self-perception and negative perceptions of life), and preventive behaviors (hygiene habits, reducing public activities, and helping others to prevent the epidemic). Results: The majority of participants in the study were knowledgeable about COVID-19. The mean COVID-19 knowledge score was 12.86 (SD = 1.34, range: 7−15 with a full score of 15), indicating a high level of knowledge. However, the key to decide whether participants adopt COVID-19 preventive behaviors was mainly their affective attitudes, especially positive affective attitudes (β = 0.18−0.25, p< 0.01), rather than COVID-19 disease knowledge (β = −0.01−0.08, p > 0.05). In addition, the sociodemographic status of the participants revealed obvious differences in the preventive behaviors; females had better preventive behaviors than males such as cooperating with the epidemic prevention hygiene habits (t = −5.08, p< 0.01), reducing public activities (t = −3.00, p< 0.01), and helping others to prevent the epidemic (t = −1.97, p< 0.05), while the older participants were more inclined to adopt preventive behaviors including epidemic prevention hygiene habits (β = 0.18, p = 0.001, R2 = 0.03), reducing public activities (β = 0.35, p< 0.001, R2 = 0.13), and helping others to prevent the epidemic (β = 0.27, p< 0.001, R2 = 0.07). Conclusions: Having adequate COVID-19 knowledge was not linked to higher involvement in precautionary behaviors. Attitudes toward COVID-19 may play a more critical function in prompting individuals to undertake preventive behaviors, and different positive affective attitudes had different predictive relationships with preventive behaviors.

Genomic, immunological and clinical analysis of COVID-19 vaccine breakthrough infections in Beijing, China

As the COVID-19 pandemic is still ongoing and SARS-CoV-2 variants are circulating worldwide, an increasing number of breakthrough infections are being detected despite the good efficacy of COVID-19 vaccines. Data on 88 COVID-19 breakthrough cases (breakthrough infections group) and 41 unvaccinated cases (unvaccinated group) from 1 June to 22 August, 2021, were extracted from a cloud database established at Beijing Ditan Hospital to evaluate the clinical, immunological and genomic characteristics of COVID-19 breakthrough infections. Among these 129 COVID-19 cases, 33 whole genomes were successfully sequenced, of which 23 were Delta variants, including 15 from the breakthrough infections group. Asymptomatic and mild cases predominated in both groups, but 2 patients developed severe disease in the unvaccinated group. The median time of viral shedding in the breakthrough infections group was significantly lower than that in the unvaccinated group (P = 0.003). In the breakthrough infections group, the IgG titres showed a significantly increasing trend (P =0.007), and the CD4+ T lymphocyte count was significantly elevated (P=0.018). For people infected with the Delta variant in the two groups, no significant difference was observed in either the RT-qPCR results or viral shedding time. In conclusion, among vaccinated patients, the cases of COVID-19 vaccine breakthrough infections were mainly asymptomatic and mild, IgG titres were significantly increased and rose rapidly, and the viral shedding time was shorter. This article is protected by copyright. All rights reserved.

Natural products as a source of novel drugs for treating SARS-CoV2 infection

COVID-19, the infectious disease caused by the beta-corona virus SARS-CoV2, has posed a global health threat causing more than five million of deaths in the last two years in the world. Although the disease often presents with mild cold-like symptoms, it may have lethal consequences following thromboembolisms, hyperinflammation and cytokine storm eventually leading to pulmonary fibrosis and multiple organ failure.

Despite the progress made in the understanding of the SARS-CoV2 pathology and the clinical management of COVID-19, the viral illness is still a health concern since outbreaks continue to resurge due to the emergence of mutant variants of the virus that resist the vaccines.

Therefore, there is an urgent need for therapeutics that can block SARS-CoV2 viral transmission and the progression from infection to severe symptomatic illness.

Natural products could be a valuable source of drugs for the management of COVID-19 disease, particularly because they can act on multitargets and through different mechanisms including inhibition of biochemical pathways, epigenetic regulation of gene expression, modulation of immune response, regulation of pathophysiological stress response.

Here we present an overview of the natural products that possess SARS-CoV2 antiviral activity and the potential to benefit the management of COVID-19.

Genomic Surveillance for Monitoring Variants of Concern: SARS-CoV-2 Delta, Omicron, and Beyond

The continuing emergence of new SARS-CoV-2 variants has perpetuated the current pandemic far beyond initial expectations. It is now likely that this virus is here to stay. Thus, a new infrastructure is required for monitoring and tracking of viral outbreaks which includes epidemiological and genomic surveillance. More effective monitoring will support rapid response times required for development of new treatments and vaccines to help manage the spread of the current virus and prepare the platforms required for future pandemics.

Epidemiological and clinical characteristics of vaccinated COVID-19 patients: A meta-analysis and systematic review

Objective: With the global epidemic of coronavirus disease 2019 (COVID-19), vaccination rates are increasing globally. This study evaluated the relevant clinical manifestations of vaccinated COVID-19 patients. Methods: We searched carefully in 11 databases such as PubMed, Embase, Scopus, Cochrane Library, Web of Science, Ovid, China National Knowledge Infrastructure Database, Wan Fang Data, Sinomed, VIP Database, and Reading Showing Database up to 26 March 2022. To search for articles that have described the characteristics of vaccinated patients including epidemiological and clinical symptoms. Statistical analysis of the extracted data using STATA 14.0. Results: A total of 58 articles and 263,708 laboratory-confirmed COVID-19 patients were included. Most of the patients in the vaccinated group had more asymptomatic infection and fewer severe illnesses. There were significant differences in ethnicity, and strain infected with COVID-19, and comorbidities (hyperlipidemia, diabetes, obesity, kidney disease, immunocompromised, cardiovascular disease, and tumor) and symptoms (fever, cough, gastrointestinal symptoms, neurological symptoms, and dysgeusia/anosmia) between vaccinated group and unvaccinated group. Oxygen support, use of steroid, days in hospital, hospital treatment, ICU treatment, death, and poor prognosis were also significantly different. Conclusion: Compared with the vaccinated group, patients in the unvaccinated group had a more severe clinical manifestations. Vaccines are also protective for infected people.