Displaying publications 101 - 120 of 743 in total

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  1. Toh TH, Qi YY, Yong SM, Lee JS, Liyana NF, See RY, et al.
    Hum Vaccin Immunother, 2023 Dec 31;19(1):2167438.
    PMID: 36705277 DOI: 10.1080/21645515.2023.2167438
    The effectiveness of the vero cell inactivated vaccine (CoronaVac®) against severe acute respiratory infection (‎SARI)‎ caused by SARS-CoV-2 in the real world was assessed. A matched test-negative case-control design was employed using the web-based national information system, as well as the hospitalization dataset in Sibu Hospital. Vaccine effectiveness was measured by conditional logistic regression with adjustment for gender, underlying comorbidity, smoking status, and education level. Between 15 March and 30 September 2021, 838 eligible SARI patients were identified from the hospitalization records. Vaccine effectiveness was 42.4% (95% confidence interval [CI]: -28.3 to 74.1) for partial vaccination (after receiving the first dose to 14 days after receiving the second dose), and 76.5% (95% CI: 45.6 to 89.8) for complete vaccination (at 15 days or more after receiving the second dose). This analysis indicated that two doses of CoronaVac® vaccine provided efficacious protection against SARI caused by SARS-CoV-2 in the short term. However, the duration of protection, and performance against new variants need to be studied continuously.
    Matched MeSH terms: Vaccines*
  2. Qureshi A, Syed Sulaiman SA, Rehman W, Mehmood A, Idrees S, Kumar N
    PLoS One, 2023;18(5):e0285736.
    PMID: 37220099 DOI: 10.1371/journal.pone.0285736
    BACKGROUND: The response to the vaccine may vary among individuals. Hence, it is important to know how often individuals experience side effects after immunization against COVID-19.

    OBJECTIVE: This study aimed to assess the incidence of side effects following COVID-19 vaccination across different vaccine recipients in Southern Pakistan and identify the potential factors associated with these side effects in the population.

    METHODS: The survey was conducted across Pakistan through Google-forms Links from August to October 2021. The questionnaire included demographic information and COVID-19 vaccine information. Chi-square (x2) was performed for comparative analysis to check the significance level with P <0.05. The final analysis included 507 participants who had received COVID-19 vaccines.

    RESULTS: Of the total 507 COVID-19 vaccines recipients, 24.9% received CoronaVac, 36.5% received BBIBP-CorV, 14.2% received BNT162b2, 13.8% received AZD1222, and 10.7% received mRNA-1273. The most prominent side effects after the first dose were fever, weakness, lethargy, and pain at the site of injection. Moreover, the most commonly reported side effects after the second dose were pain at the injection site, headache, body ache, lethargy, fever, chills, flu-like symptoms, and diarrhea.

    CONCLUSION: Our results suggested that the side effects due to COVID-19 vaccination can vary between the first and second doses and type of COVID-19 vaccine. Our findings suggest continuing monitoring of vaccine safety and the importance of individualized risk-benefit assessment for COVID-19 immunization.

    Matched MeSH terms: Vaccines*
  3. Salman M, Mallhi TH, Khan YH, Mustafa ZU, Khan MT, Khan FU, et al.
    Hum Vaccin Immunother, 2023 Aug 01;19(2):2225990.
    PMID: 37350298 DOI: 10.1080/21645515.2023.2225990
    Vaccine hesitancy (VH) is not a new phenomenon in Pakistan and is regarded as one of the primary causes of unsatisfactory vaccination campaigns. This study determined post-vaccination COVID-19 VH, factors influencing COVID-19 vaccine uptake, and public's intent to receive booster vaccinations. A cross-sectional study was conducted among adult population of Lahore, Pakistan. Participants were recruited via convenience sampling between March and May 2022. SPSS version 22 was used for the data analysis. A total of 650 participants were included in the study (age = 28.1 ± 9.7 years; male-to-female ratio nearly 1: 1). The majority of participants received Sinopharm followed by Sinovac vaccine. The top three reasons of vaccine uptake were "only vaccinated individuals are allowed at the workplace, and educational institutes" (Relative importance index (RII) = 0.749), "only vaccinated people are allowed to go to markets, malls and other public places" (RII = 0.746), and "protect myself from the infection" (RII = 0.742). The mean COVID-19 VH score was 24.5 ± 6.2 (95% CI 23.9-24.9), with not being pro-vaccines and poor economic status were the significant predictors of COVID-19 vaccine hesitancy among immunized individuals (p 
    Matched MeSH terms: Vaccines*
  4. Feizollah A, Anuar NB, Mehdi R, Firdaus A, Sulaiman A
    Int J Environ Res Public Health, 2022 May 21;19(10).
    PMID: 35627806 DOI: 10.3390/ijerph19106269
    The COVID-19 pandemic introduced unprecedented challenges for people and governments. Vaccines are an available solution to this pandemic. Recipients of the vaccines are of different ages, gender, and religion. Muslims follow specific Islamic guidelines that prohibit them from taking a vaccine with certain ingredients. This study aims at analyzing Facebook and Twitter data to understand the discourse related to halal vaccines using aspect-based sentiment analysis and text emotion analysis. We searched for the term "halal vaccine" and limited the timeline to the period between 1 January 2020, and 30 April 2021, and collected 6037 tweets and 3918 Facebook posts. We performed data preprocessing on tweets and Facebook posts and built the Latent Dirichlet Allocation (LDA) model to identify topics. Calculating the sentiment analysis for each topic was the next step. Finally, this study further investigates emotions in the data using the National Research Council of Canada Emotion Lexicon. Our analysis identified four topics in each of the Twitter dataset and Facebook dataset. Two topics of "COVID-19 vaccine" and "halal vaccine" are shared between the two datasets. The other two topics in tweets are "halal certificate" and "must halal", while "sinovac vaccine" and "ulema council" are two other topics in the Facebook dataset. The sentiment analysis shows that the sentiment toward halal vaccine is mostly neutral in Twitter data, whereas it is positive in Facebook data. The emotion analysis indicates that trust is the most present emotion among the top three emotions in both datasets, followed by anticipation and fear.
    Matched MeSH terms: Vaccines*
  5. Aljunid SM, Mad Tahir NS, Ismail A, Abdul Aziz AF, Azzeri A, Zafirah SA, et al.
    Sci Rep, 2023 Oct 31;13(1):18771.
    PMID: 37907537 DOI: 10.1038/s41598-023-46079-y
    The economic burden of influenza is a significant issue within healthcare system, related to higher medical costs particularly among the elderly. Yet, influenza vaccination rates in the elderly in Malaysia were considerably low as it is not part of Malaysia's national immunization program, with substantial mortality and morbidity consequences. Therefore, we conducted a cost-effectiveness analysis of quadrivalent influenza vaccine (QIV) for the elderly in Malaysia compared with the current no-vaccination policy. A static cost-utility model, with a lifetime horizon based on age, was used for the analysis to assess the cost-effectiveness and health outcomes associated with QIV. Univariate and probabilistic sensitivity analyses were performed to test the effects of variations in the parameters. The use of QIV in Malaysia's elderly population would prevent 66,326 potential influenza cases and 888 potential deaths among the elderly, leading to 10,048 potential quality-adjusted life years (QALYs) gained. The QIV would also save over USD 4.4 million currently spent on influenza-related hospitalizations and reduce productivity losses by approximately USD 21.6 million. The ICER per QALY gained from a third-party payer's perspective would be USD 2216, which is lower than the country's gross domestic product per capita. A QIV-based vaccination program in the elderly was found to be highly cost-effective, therefore would reduce the financial burden of managing influenza and reduce pre-mature death related to this disease.
    Matched MeSH terms: Influenza Vaccines*
  6. Syed Alwi SAR, Rafidah E, Zurraini A, Juslina O, Brohi IB, Lukas S
    BMC Public Health, 2021 06 12;21(1):1129.
    PMID: 34118897 DOI: 10.1186/s12889-021-11071-6
    BACKGROUND: Vaccination is an effective way to curtail the burden of COVID-19 in which success depends on a high acceptance of the vaccine. However, addressing concerns among vaccine-hesitant individuals is essential to avoid failure of the immunisation programme. This study sought to assess the concerns and acceptance rates regarding the COVID-19 vaccine among Malaysians.

    METHODS: An online questionnaire was distributed to 1411 respondents via a snowball sampling method among Malaysians aged 18 years and above.

    RESULTS: The majority of the respondents were young adults (40.7%), female (62.8%), Malay (63.8%), Muslim (72.3%), married (52.9%), with tertiary education (86.8%) and without medical illness (85%). Social media (97.4%) was the primary source of information regarding COVID-19. The overall acceptance rate was high (83.3%), with the lowest rates among the elderly aged 60 years and above (63.4%) and pensioners (64.6%). Hesitance was caused by concerns regarding side effects (95.8%), safety (84.7%), lack of information (80.9%), effectiveness (63.6%) and religious (20.8%) and cultural factors related to the COVID-19 vaccine (6.8%). Respondents with diabetes mellitus (24.7%) and hypercholesterolemia (23%) were more hesitant to accept the COVID-19 vaccine, at 16.1 and 15.8%, respectively. Predictors of COVID-19 vaccine hesitance were age, religion, and current residence.

    CONCLUSIONS: The results indicate a high rate of acceptance of the COVID-19 vaccine among Malaysians. Thus, the Malaysian government and other related agencies should increase their campaign and prepare to implement the COVID-19 mass immunisation programme among Malaysians. However, despite the high acceptance rate, it remains important to address concerns among hesitant individuals by building trust in vaccine safety and effectiveness through adequate information regarding the vaccine.

    Matched MeSH terms: Vaccines*
  7. van Doremalen N, Lambe T, Sebastian S, Bushmaker T, Fischer R, Feldmann F, et al.
    PLoS Negl Trop Dis, 2019 Jun;13(6):e0007462.
    PMID: 31170144 DOI: 10.1371/journal.pntd.0007462
    Nipah virus (NiV) is a highly pathogenic re-emerging virus that causes outbreaks in South East Asia. Currently, no approved and licensed vaccine or antivirals exist. Here, we investigated the efficacy of ChAdOx1 NiVB, a simian adenovirus-based vaccine encoding NiV glycoprotein (G) Bangladesh, in Syrian hamsters. Prime-only as well as prime-boost vaccination resulted in uniform protection against a lethal challenge with NiV Bangladesh: all animals survived challenge and we were unable to find infectious virus either in oral swabs, lung or brain tissue. Furthermore, no pathological lung damage was observed. A single-dose of ChAdOx1 NiVB also prevented disease and lethality from heterologous challenge with NiV Malaysia. While we were unable to detect infectious virus in swabs or tissue of animals challenged with the heterologous strain, a very limited amount of viral RNA could be found in lung tissue by in situ hybridization. A single dose of ChAdOx1 NiVB also provided partial protection against Hendra virus and passive transfer of antibodies elicited by ChAdOx1 NiVB vaccination partially protected Syrian hamsters against NiV Bangladesh. From these data, we conclude that ChAdOx1 NiVB is a suitable candidate for further NiV vaccine pre-clinical development.
    Matched MeSH terms: Vaccines, Synthetic/administration & dosage; Vaccines, Synthetic/genetics; Vaccines, Synthetic/immunology; Viral Vaccines/administration & dosage; Viral Vaccines/genetics; Viral Vaccines/immunology*
  8. Mohamad E, Tham JS, Mohd Ajis SZ, Hamzah MR, Ayub SH, Tri Sakti AM, et al.
    Int J Environ Res Public Health, 2022 Nov 08;19(22).
    PMID: 36429342 DOI: 10.3390/ijerph192214623
    INTRODUCTION: This study explored exposure to misinformation, COVID-19 risk perception, and confidence towards the government as predictors of negative attitudes toward the COVID-19 vaccine.

    METHODS: A cross-sectional survey was carried out from 30 June to 30 August 2021 involving 775 respondents. The survey instrument for the questionnaire was an adaptation from various different studies consisting of five main variables: (1) misinformation about vaccination; (2) risk perception toward COVID-19; (3) attitudes toward the vaccination programme; (4) intention to get vaccinated; and (5) public confidence in the government in executing the vaccination programme.

    RESULTS: The results of this study indicate that higher exposure to misinformation led to higher levels of negative attitudes toward the COVID-19 vaccine. When the perceived risk of COVID-19 infection was high, mistrust of vaccine benefits was low but there were also higher worries about the future effects of the vaccine. Confidence in the government was associated with lower negative attitudes toward the COVID-19 vaccine.

    CONCLUSION: The results of this study may help develop an understanding of negative attitudes toward vaccinations in Malaysia and its contributing factors.

    Matched MeSH terms: Vaccines*
  9. Al-Hatamleh MAI, Hatmal MM, Alshaer W, Rahman ENSEA, Mohd-Zahid MH, Alhaj-Qasem DM, et al.
    Eur J Pharmacol, 2021 Apr 05;896:173930.
    PMID: 33545157 DOI: 10.1016/j.ejphar.2021.173930
    The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which emerged in December 2019 and caused the coronavirus disease 2019 (COVID-19) pandemic, took the world by surprise with an unprecedented public health emergency. Since this pandemic began, extraordinary efforts have been made by scientists to understand the pathogenesis of COVID-19, and to fight the infection by providing various preventive, diagnostic and treatment opportunities based on either novel hypotheses or past experiences. Despite all the achievements, COVID-19 continues to be an accelerating health threat with no specifically approved vaccine or therapy. This review highlights the recent advances in COVID-19 infection, with a particular emphasis on nanomedicine applications that can help in the development of effective vaccines or therapeutics against COVID-19. A novel future perspective has been proposed in this review based on utilizing polymersome nano-objects for effectively suppressing the cytokine storm, which may reduce the severity of COVID-19 infection.
    Matched MeSH terms: Viral Vaccines/pharmacology*
  10. Tieng FYF, Lee LH, Ab Mutalib NS
    Front Immunol, 2022;13:959705.
    PMID: 36032085 DOI: 10.3389/fimmu.2022.959705
    Single cell RNA sequencing (scRNA-seq) is a novel high-throughput technique that enables the investigation of a single cell's entire transcriptome. It elucidates intricate cellular networks and generates indices that will eventually enable the development of more targeted and personalized medications. The importance of scRNA-seq has been highlighted in complex biological systems such as cancer and the immune system, which exhibit significant cellular heterogeneity. Colorectal cancer (CRC) is the third most common type of cancer and the second leading cause of cancer-related death globally. Chemotherapy continues to be used to treat these patients. However, 5-FU has been utilized in chemotherapy regimens with oxaliplatin and irinotecan since the 1960s and is still used today. Additionally, chemotherapy-resistant metastatic CRCs with poor prognoses have been treated with immunotherapy employing monoclonal antibodies, immune checkpoint inhibitors, adoptive cell therapy and cancer vaccines. Personalized immunotherapy employing tumor-specific neoantigens allows for treating each patient as a distinct group. Sequencing and multi-omics approaches have helped us identify patients more precisely in the last decade. The introduction of modern methods and neoantigen-based immunotherapy may usher in a new era in treating CRC. The unmet goal is to better understand the cellular and molecular mechanisms that contribute to CRC pathogenesis and resistance to treatment, identify novel therapeutic targets, and make more stratified and informed treatment decisions using single cell approaches. This review summarizes current scRNA-seq utilization in CRC research, examining its potential utility in the development of precision immunotherapy for CRC.
    Matched MeSH terms: Cancer Vaccines*
  11. Le CF, Palanisamy NK, Mohd Yusof MY, Sekaran SD
    PLoS One, 2011;6(5):e19547.
    PMID: 21603602 DOI: 10.1371/journal.pone.0019547
    BACKGROUND: Streptococcus pneumoniae is a major causative agent of severe infections, including sepsis, pneumonia, meningitis, and otitis media, that has since become a major public health concern. In this study, the serotypes distribution of pneumococcal isolates was investigated to predict the efficacy of the 7-valent pneumococcal conjugate vaccine (PCV7) among the Malaysian populations.
    METHODOLOGY/PRINCIPAL FINDINGS: A total of 151 clinical isolates were serotyped using multiplex PCR assays. Out of them, there were 21.2% penicillin-resistant, 29.1% penicillin-intermediate, and 49.7% penicillin-susceptible S. pneumoniae strains. Serotypes detected among the Malaysian isolates were 1, 3, 10A, 11A/11D, 12F/12A, 14, 15A, 15B/15C, 16F, 18C/18B/18A/18F, 19A, 19F, 23F, 35B, 35F/47F, 6A/6B, 7C/7B/40, 7F/7A, 9V/9A, and 34. Serotype 19F and 23F were the two most prevalent serotypes detected. Serotypes are highly associated with invasiveness of isolates (p = 0.001) and penicillin susceptibility (p<0.001). Serotype 19F was observed to have increased resistance against penicillin while serotype 19A has high invasive tendency. Age of patients was an important factor underlying the pneumococcal serotypes (p = 0.03) and clinical sites of infections (p<0.001). High prevalence of pneumococcal isolates were detected among children <5 years old at nasopharyngeal sites while elderly adults ≥60 years old were at increased risk for pneumococcal bacteremia.
    CONCLUSION/SIGNIFICANCE: Current study revealed that a number of serotypes, especially those associated with high penicillin resistance, have been formulated in the PCV7. Therefore, the protections expected from the routine use of PCV7 would be encouraging for the Malaysian. However, it is not possible to predict serotypes that might become predominant in the future and hence continued surveillance of circulating serotypes will be needed.
    Matched MeSH terms: Vaccines, Conjugate/immunology*; Pneumococcal Vaccines/immunology*
  12. Lee MS, Chang LY
    Expert Rev Vaccines, 2010 Feb;9(2):149-56.
    PMID: 20109026 DOI: 10.1586/erv.09.152
    Enterovirus 71 (EV71) was first isolated in 1969 in California, USA. Several epidemic outbreaks with high mortality rates have occurred in European and Asian Countries (Bulgaria in 1975, Hungary in 1978, Malaysia in 1997, Taiwan in 1998 and China in 2008). EV71 CNS involvement may be associated with neurological sequelae, delayed neurodevelopment and reduced cognitive functioning. Since poliovirus was nearly eradicated by vaccination, EV71 is now considered as one of the top candidates for new vaccine development against human enteroviruses. Recently, several EV71 vaccine candidates, including live-attenuated virus, inactivated whole virus, recombinant viral protein, virus-like particle and DNA vaccines, have been evaluated in animals but no clinical trial has yet been conducted. Based on historical experiences with poliovirus vaccines and animal studies, the inactivated whole-virus vaccines are feasible and could be licensed readily, so these are targeted for preparing clinical trials in several organizations in Asia.
    Matched MeSH terms: Viral Vaccines/immunology*; Vaccines, Inactivated/immunology
  13. Devine VT, Jefferies JM, Clarke SC, Faust SN
    J Immunol Res, 2015;2015:394368.
    PMID: 26351646 DOI: 10.1155/2015/394368
    Seven-valent pneumococcal conjugate vaccine (PCV7) was included in the UK national immunisation program in 2006, and this was replaced by thirteen-valent PCV in 2010. During this time, the carriage of vaccine-type Streptococcus pneumoniae decreased but pneumococcal carriage remained stable due to increases in non-vaccine-type S. pneumoniae. Carriage studies have been undertaken in various countries to monitor vaccine-type replacement and to help predict the serotypes, which may cause invasive disease. There has been less focus on how conjugate vaccines indirectly affect colonization of other nasopharyngeal bacteria. If the nasopharynx is treated as a niche, then bacterial dynamics are accepted to occur. Alterations in these dynamics have been shown due to seasonal changes, antibiotic use, and sibling/day care interaction. It has been shown that, following PCV7 introduction, an eradication of pneumococcal vaccine types has resulted in increases in the abundance of other respiratory pathogens including Haemophilus influenzae and Staphylococcus aureus. These changes are difficult to attribute to PCV7 introduction alone and these studies do not account for further changes due to PCV13 implementation. This review aims to describe nasopharyngeal cocarriage of respiratory pathogens in the PCV era.
    Matched MeSH terms: Vaccines, Conjugate/immunology*; Pneumococcal Vaccines/immunology*
  14. Joan SS, Pui-Fong J, Song AA, Chang LY, Yusoff K, AbuBakar S, et al.
    Biotechnol Lett, 2016 May;38(5):793-9.
    PMID: 26758876 DOI: 10.1007/s10529-016-2034-2
    An oral lactococcal-based vaccine which haboured the haemagglutinin1 (HA1) antigen fused to nisP anchor protein for the purpose of surface displaying the HA1 antigen was developed against H1N1 virus.
    Matched MeSH terms: Influenza Vaccines
  15. Mohd Nazir Mohd Nazori, Rohani Ismail, Nur Syahmina Rasudin
    MyJurnal
    Introduction: Vaccine hesitancy is “to delay in acceptance or refusal of vaccination despite availability of vacci-nation services. Vaccine hesitancy is complex and context specific, varying across time, place and vaccines...”. National vaccination data showed presence of hesitancy and the potential for others to develop hesitancy. An over-view of vaccine hesitancy is needed to organise our understanding and to focus our efforts in health promotion. The objectives of this review were to (1) describe the scope of vaccine hesitancy involving target population, theoretical developments and practical implications and (2) to identify potential research avenues for health promotion in Ma-laysia. Methods: Scoping review methodology was used. Search strategy utilised keywords for publications from the year 2000 onwards with a focus on local parental vaccine hesitancy. Literature review focused on global theoretical development and analysis were done on local empirical findings. Results: Theoretical developments have led to the Vaccine Hesitancy Determinant Matrix (VHDM) describing factors within three themes: “vaccine/vaccination-specif-ic issues”, “individual or group influence” and “contextual influence”. Parents can be classified into ‘unquestioning acceptor’, ‘cautious acceptor’, ‘hesitant’, ‘late or selective vaccinator’ and the ‘refuser’ of all vaccines. Globally, various mode of interventions has been explored. However, there was a disproportionate focus on knowledge, at-titude and practice research among local parents. There were only two local interventional studies that have been published. Conclusion: There is a dearth of interventional studies locally. Each of the parental groups outlined needs a tailored approach to combat vaccine hesitancy. Global interventional research showed a multitude of approaches towards educational intervention that local researchers should capitalise on developing strategies, techniques and modules for the local population.
    Matched MeSH terms: Vaccines
  16. Hoo WPY, Siak PY, In LLA
    Methods Mol Biol, 2020;2131:213-228.
    PMID: 32162256 DOI: 10.1007/978-1-0716-0389-5_10
    Discovery of tumor antigenic epitopes is important for cancer vaccine development. Such epitopes can be designed and modified to become more antigenic and immunogenic in order to overcome immunosuppression towards the native tumor antigen. In silico-guided modification of epitope sequences allows predictive discrimination of those that may be potentially immunogenic. Therefore, only candidates predicted with high antigenicity will be selected, constructed, and tested in the lab. Here, we described the employment of in silico tools using a multiparametric approach to assess both potential T-cell epitopes (MHC class I/II binding) and B-cell epitopes (hydrophilicity, surface accessibility, antigenicity, and linear epitope). A scoring and ranking system based on these parameters was developed to shortlist potential mimotope candidates for further development as peptide cancer vaccines.
    Matched MeSH terms: Cancer Vaccines/immunology*; Vaccines, Subunit/immunology
  17. Anasir MI, Poh CL
    Int J Mol Sci, 2019 Mar 13;20(6).
    PMID: 30871133 DOI: 10.3390/ijms20061256
    Hand, foot, and mouth disease (HFMD) commonly produces herpangina, but fatal neurological complications have been observed in children. Enterovirus 71 (EV-A71) and Coxsackievirus 16 (CV-A16) are the predominant viruses causing HFMD worldwide. With rising concern about HFMD outbreaks, there is a need for an effective vaccine against EV-A71 and CV-A16. Although an inactivated vaccine has been developed against EV-A71 in China, the inability of the inactivated vaccine to confer protection against CV-A16 infection and other HFMD etiological agents, such as CV-A6 and CV-A10, necessitates the exploration of other vaccine platforms. Thus, the antigenic peptide-based vaccines are promising platforms to develop safe and efficacious multivalent vaccines, while the monoclonal antibodies are viable therapeutic and prophylactic agents against HFMD etiological agents. This article reviews the available information related to the antigenic peptides of the etiological agents of HFMD and their neutralizing antibodies that can provide a basis for the design of future therapies against HFMD etiological agents.
    Matched MeSH terms: Viral Vaccines/immunology*; Vaccines, Subunit/immunology*
  18. Xian TH, Sinniah K, Yean CY, Krishnamoorthy V, Bahari MB, Ravichandran M, et al.
    BMC Immunol, 2020 05 25;21(1):29.
    PMID: 32450807 DOI: 10.1186/s12865-020-00360-1
    BACKGROUND: Cholera, an acute watery diarrhoeal disease caused by Vibrio cholerae serogroup O1 and O139 across the continents. Replacing the existing WHO licensed killed multiple-dose oral cholera vaccines that demand 'cold chain supply' at 2-8 °C with a live, single-dose and cold chain-free vaccine would relieve the significant bottlenecks and cost determinants in cholera vaccination campaigns. In this direction, a prototype cold chain-free live attenuated cholera vaccine formulation (LACV) was developed against the toxigenic wild-type (WT) V. cholerae O139 serogroup. LACV was found stable and retained its viability (5 × 106 CFU/mL), purity and potency at room temperature (25 °C ± 2 °C, and 60% ± 5% relative humidity) for 140 days in contrast to all the existing WHO licensed cold-chain supply (2-8 °C) dependent killed oral cholera vaccines.

    RESULTS: The LACV was evaluated for its colonization potential, reactogenicity, immunogenicity and protective efficacy in animal models after its storage at room temperature for 140 days. In suckling mice colonization assay, the LACV recorded the highest recovery of (7.2 × 107 CFU/mL) compared to those of unformulated VCUSM14P (5.6 × 107 CFU/mL) and the WT O139 strain (3.5 × 107 CFU/mL). The LACV showed no reactogenicity even at an inoculation dose of 104-106 CFU/mL in a rabbit ileal loop model. The rabbits vaccinated with the LACV or unformulated VCUSM14P survived a challenge with WT O139 and showed no signs of diarrhoea or death in the reversible intestinal tie adult rabbit diarrhoea (RITARD) model. Vaccinated rabbits recorded a 275-fold increase in anti-CT IgG and a 15-fold increase in anti-CT IgA antibodies compared to those of rabbits vaccinated with unformulated VCUSM14P. Vibriocidal antibodies were increased by 31-fold with the LACV and 14-fold with unformulated VCUSM14P.

    CONCLUSION: The vaccine formulation mimics a natural infection, is non-reactogenic and highly immunogenic in vivo and protects animals from lethal wild-type V. cholerae O139 challenge. The single dose LACV formulation was found to be stable at room temperature (25 ± 2 °C) for 140 days and it would result in significant cost savings during mass cholera vaccination campaigns.

    Matched MeSH terms: Vaccines, Attenuated/immunology*; Cholera Vaccines/immunology*
  19. Yee PTI, Laa Poh C
    Virology, 2017 06;506:121-129.
    PMID: 28384566 DOI: 10.1016/j.virol.2017.03.017
    Enterovirus-A71 (EV-A71) is an etiological agent of the hand, foot and mouth disease (HFMD). EV-A71 infection produces high fever and ulcers in children. Some EV-A71 strains produce severe infections leading to pulmonary edema and death. Although the protective efficacy of the inactivated vaccine (IV) was ≥90% against mild HFMD, there was approximately 80% protection against severe HFMD. The monovalent EV-A71 IV elicits humoral immunity but lacks long-term immunogenicity. Spontaneous mutations of the EV-A71 genome could lead to antigenicity changes and the virus may not be neutralized by antibodies elicited by the IV. A better alternative would be the live attenuated vaccine (LAV) that elicits cellular and humoral immunity. The LAV induces excellent antigenicity and chances of reversion is reduced by presence of multiple mutations which could reduce pathogenicity. Besides CV-A16, outbreaks have been caused by CV-A6 and CV-A10, hence the development of bivalent and trivalent vaccines is required.
    Matched MeSH terms: Viral Vaccines/administration & dosage; Viral Vaccines/genetics; Viral Vaccines/immunology*
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