• Clinical and Experimental Vaccine Research
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• v.12 no.4
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• pp.337-345
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• 2023

Purpose: The global fight against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has led to widespread vaccination efforts, yet the optimal dosing schedule for SARS-CoV-2 vaccines remains a subject of ongoing research. This study aims to investigate the effectiveness of administering two booster doses as the third and fourth doses at different intervals to enhance vaccine protection. Materials and Methods: This study was conducted at a military regional hospital operated by the Ministry of National Defense in Taiwan. A cohort of vaccinated individuals was selected, and their vaccine potency was assessed at various time intervals following their initial vaccine administration. The study participants received booster doses as the third and fourth doses, with differing time intervals between them. The study monitored neutralizing antibody titers and other relevant parameters to assess vaccine efficacy. Results: Our findings revealed that the potency of the SARS-CoV-2 vaccine exhibited a significant decline 80 days after the initial vaccine administration. However, a longer interval of 175 days between booster injections resulted in significantly higher neutralizing antibody titers. The individuals who received the extended interval boosters exhibited a more robust immune response, suggesting that a vaccine schedule with a 175-day interval between injections may provide superior protection against SARS-CoV-2. Conclusion: This study underscores the importance of optimizing vaccine booster dosing schedules to maximize protection against SARS-CoV-2. The results indicate that a longer interval of 175 days between the third and fourth doses of the vaccine can significantly enhance the neutralizing antibody response, potentially offering improved protection against the virus. These findings have important implications for vaccine distribution and administration strategies in the ongoing battle against the SARS-CoV-2 pandemic. Further research and largescale trials are needed to confirm and extend these findings for broader public health implications.

• Asian Journal of Innovation and Policy
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• v.9 no.2
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• pp.106-132
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• 2020

This study intends to add a factor to the discussion on the sectoral systems of innovation through Korea's response to the COVID-19 pandemic. The Korean approach is summarized as follows: the first response centers on technology and innovation. These include the development of diagnostic test methods and accurate test kits, first in the world, the use of ICT technology in epidemiological investigations, the technical response in the field, and the competitive edge in the development of medicine and vaccines that were behind the developed countries. The second response is an aggressive effort implemented just after the Chinese announcement, before the domestic outbreak; the third response is the open policy that induces voluntary participation of all subjects and people by opening all information. More important is the leadership at the national level shown in the past Korean experience and most advanced countries. National leadership must be the missing factor.

• IMMUNE NETWORK
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• v.22 no.5
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• pp.41.1-41.16
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• 2022

The human antimicrobial peptide LL-37 has chemotactic and modulatory activities in various immune cells, including dendritic cells. Because of its characteristics, LL-37 can be considered an adjuvant for vaccine development. In this study, we confirmed the possible adjuvant activity of LL-37 in mucosal vaccine development against Middle East respiratory syndrome-coronavirus (MERS-CoV) by means of intranasal immunization in C57BL/6 and human dipeptidyl peptidase 4 (hDPP4)-transgenic (hDPP4-Tg) mice. Intranasal immunization using the receptor-binding domain (RBD) of MERS-CoV spike protein (S-RBD) recombined with LL-37 (S-RBD-LL-37) induced an efficient mucosal IgA and systemic IgG response with virus-neutralizing activity, compared with S-RBD. Ag-specific CTL stimulation was also efficiently induced in the lungs of mice that had been intranasally immunized with S-RBD-LL-37, compared with S-RBD. Importantly, intranasal immunization of hDPP4-Tg mice with S-RBD-LL-37 led to reduced immune cell infiltration into the lungs after infection with MERS-CoV. Finally, intranasal immunization of hDPP4-Tg mice with S-RBD-LL-37 led to enhanced protective efficacy, with increased survival and reduced body weight loss after challenge infection with MERS-CoV. Collectively, these results suggest that S-RBD-LL-37 is an effective intranasal vaccine candidate molecule against MERS-CoV infection.

• Clinical and Experimental Vaccine Research
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• v.12 no.3
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• pp.209-215
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• 2023

Purpose: The delay in acceptance or refusal to get vaccinated despite the availability of services is called vaccine hesitancy. The Global Polio Eradication Initiative in Pakistan faced consistent barriers preventing the eradication of the disease in the country. Similarly with the advent of the coronavirus disease 2019 (COVID-19) pandemic mass vaccination drives were initiated to a vaccine hesitant population. The aim of this study is to explore the prevalence and reasons for COVID-19 vaccine hesitancy in the Pakistani population. Materials and Methods: Cross-sectional study conducted during July to September 2021 using a snowball sampling technique targeting the adult population of Pakistan. The modified version of the vaccine hesitancy questionnaire related to the Strategic Advisory Group of Experts on Immunization Vaccine Hesitancy matrix was distributed online. Results: Out of 973 participants, 52.4% were immediately willing to take the vaccine and constituted the acceptance group whereas the remaining 47.6% who were still not sure formed the hesitant group. Support from leaders was found to be statistically significant for the difference between the hesitant and acceptance groups (p-value=0.027). Hesitant people were concerned about the effectiveness of the vaccine (60.9%) and potential side effects (57.9%) as it was not sufficiently tested prior to launch (44.7%). Age and education were significant factors affecting the acceptance of vaccination. The most trusted source of information regarding vaccination was health care workers (43.8%). Conclusion: A moderately high prevalence of vaccine hesitancy was reported in Pakistan. To overcome it, policymakers need to address the reasons for it. Leaders, celebrities, and healthcare workers can play an instrumental role in dispelling conspiracy theories regarding vaccines and making the vaccination drive a success.

• Clinical and Experimental Vaccine Research
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• v.11 no.2
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• pp.226-229
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• 2022

A 38-year-old female patient, with healthy history, was vaccinated with ChAdOx1 nCoV-19 (Astra Zeneca Cambridge, UK). Five days after the second injection, the patient presented headache, vertigo, then fatigue, nervousness, palpitations, shortness of breath, small amplitude tremors, and sweating episodes. Laboratory investigation revealed a suppressed thyroid-stimulating hormone (TSH), with elevated free thyroxine. However, the TSH receptor antibody and anti-thyroid peroxidase antibody were normal and thyroid-stimulating immunoglobulin negative. The patient was maintained on Metoprolol, and no specific treatment was added. After 3 months of following, the patient now feels comfortable. Our literature review found that 21 cases of subacute thyroiditis (SAT) following coronavirus disease 2019 (COVID-19) vaccines were reported. Most patients were young women who presented neck pain and systemic symptoms, with or without fever. These symptoms can appear as early (3 to 5 days), or later (1 month) after vaccination, regardless of vaccine type and mechanism of action. Laboratory tests showed decreased levels of TSH and elevated thyroid hormone. The mechanism of this event remains unknown. Further study is recommended to investigate the possible predisposing factors to developing SAT after receiving the COVID-19 vaccine.

• Journal of Microbiology and Biotechnology
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• v.29 no.5
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• pp.813-819
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• 2019

Middle East respiratory syndrome coronavirus (MERS-CoV) induces severe respiratory impairment with a reported mortality rate of ~36% in humans. The absence of clinically available MERS-CoV vaccines and treatments to date has resulted in uncontrolled incidence and propagation of the virus. In vaccine design, fusion with the IgG Fc domain is reported to increase the immunogenicity of various vaccine antigens. However, limited reports have documented the potential negative effects of Fc fusion on vaccine antigens. To determine whether Fc fusion affects the immunogenicity of MERS-CoV antigen, we constructed a Fcassociated MERS-CoV spike protein (eS770-Fc, 110 kDa), whereby human IgG4 Fc domain was fused to MERS-CoV spike protein (eS770) via a Gly/Pro linker using baculovirus as the expression system. For comparative analyses, two eS770 proteins lacking the IgG4 Fc domain were generated using the IdeS protease ($eS770-{\Delta}Fc$) or His tag attachment (eS770-His) and the immunogenicity of the above constructs were examined following intramuscular immunization in mice. Contrary to expectations, non-Fc spike proteins ($eS770-{\Delta}Fc$, eS770-His; 90 kDa) showed higher immunogenicity than the Fc fusion protein (eS770-Fc). Moreover, unlike non-Fc spike proteins, eS770-Fc immunization did not elicit neutralizing antibodies against MERS-CoV. The lower immunogenicity of Fc-fused eS770 was related to alterations in the structural conformation of the spike protein. Taken together, our results indicate that IgG Fc fusion reduces the immunogenicity of eS770 by interfering with the proper folding structure.

• Clinical and Experimental Vaccine Research
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• v.12 no.4
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• pp.319-327
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• 2023

Purpose: Patients with hematological malignancies are at an increased risk of severe infection with coronavirus disease 2019 (COVID-19). However, developing an adequate immune response after vaccination is difficult, especially in patients with lymphoid neoplasms. Since the long-term effects of the BNT162b2 vaccine are unclear, the humoral immune response 5 months after the two vaccinations in patients with hematological disorders was analyzed. Materials and Methods: Samples were collected from 96 patients vaccinated twice with BNT162b2 and treated with at least one line of an antitumor or immunosuppressive drug in our hospital from November 2021 to February 2022. Serum anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) spike (S) antibody titers were analyzed. Patients were age- and sex-matched using propensity matching and compared with a healthy control group. Patients with serum anti-SARS-CoV-2 S antibodies were defined as 'responder' if >50 U/mL. The patients had B-cell non-Hodgkin lymphoma (B-NHL), multiple myeloma, chronic myeloid leukemia, etc. Results: Patients had significantly low antibody levels (median, 55.3 U/mL vs. 809.8 U/mL; p<0.001) and a significantly low response rate (p<0.001). Multivariate analysis showed that patients with B-NHL, aged >72 years, were associated with a low response to vaccination. There were no significant differences between patients with chronic myeloid leukemia and healthy controls. Conclusion: Our study shows that patients with hematological disorders are at risk of developing severe COVID-19 infections because of low responsiveness to vaccination. Moreover, the rate of antibody positivity differed between the disease groups. Further studies are warranted to determine an appropriate preventive method for these patients, especially those with B-NHL.

• Pediatric Infection and Vaccine
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• v.29 no.2
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• pp.61-69
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• 2022

Coronavirus disease 2019 (COVID-19) has been a global pandemic for over 2 years. During the Omicron (B.1.1.529) variant-predominant period in South Korea, confirmed cases among children and adolescents surged. This review found that, although younger children may be less susceptible to COVID-19 than adolescents, more research is needed on the role of children and adolescents in the disease's spread. Detailed epidemiological information about the transmissibility of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strain in children and adolescents is currently scarce, and more research is needed on the role of children and adolescents in disease's spread. There may be a difference in the proportion of cases with severe disease requiring hospitalization depending on the dominant mutant strain; however, COVID-19 generally presents with a mild-to-moderate course in children aged 5-11 years old.

• Journal of Digestive Cancer Research
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• v.10 no.2
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• pp.107-111
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• 2022

In 2019, coronavirus disease (COVID-19), which originated in Wuhan, has spread worldwide. In most people, COVID-19 symptoms are not severe. However, the mortality rate and severity were high in risk groups such as in older people and patients with underlying diseases. As patients with cancer are one of the risk groups, the vaccination for COVID-19 is emphasized in these patients. However, COVID-19 vaccines are not tested enough in special groups such as in patients with cancer because these vaccines are developed at an unprecedented speed. This causes confusion about whether patients undergoing chemotherapy should be vaccinated or not. In this study, international guidelines and studies were reviewed. Most of the studies recommended vaccination. No evidences of any negative effects for the efficacy or safety were recorded in patients undergoing cytotoxic, targeted, and immune agents. However, in critical conditions such as cytopenia, vaccination must be decided according to the patient's condition. COVID-19 vaccines were also recommended for patients on surgery or radiation therapy. If possible, vaccine is given before surgery to avoid confusion between surgical complications and side effects of the vaccine. The radiation recall phenomenon after vaccination has been reported in some cases of radiation therapy. Clinicians should consider these situations before vaccinating each patient. We hope that clearer guidelines will be established by accumulating verified data.

• Clinical and Experimental Vaccine Research
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• v.13 no.3
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• pp.259-262
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• 2024

There have been many studies on the adverse effects of coronavirus disease 2019 (COVID-19) vaccines but the urinary incontinence after COVID-19 vaccination is rare. Here, we report an 8-year-old boy presented to outpatient department, Thai Binh University of Medicine Hospital, Thai Binh, Vietnam with complaints of urinary incontinence for the past 2 weeks, following the first dose of the messenger RNA vaccine. He had no other abnormalities in clinical and laboratory exams. This clinical situation suggested vaccine side effects. No specific treatment was administered upon diagnosis without toilet and bladder training. Subsequent monitoring revealed a gradual reduction in symptoms over 2 months, with complete recovery achieved at the 14th week from the onset of symptoms, without necessitating any medical intervention. This case highlights the need for thorough evaluation and assessment of potential adverse effects following vaccination, including uncommon presentations.