Publications by authors named "Pornthep Chanthavanich"

Japanese encephalitis is the main cause of viral encephalitis in Asia. In a previous single-arm vaccine trial, an inactivated chromatographically purified Japanese encephalitis Vero cell vaccine (CVI-JE; JEVAC) was safe and immunogenic in 152 Thai children aged 1-3 years receiving a 2-dose primary immunization and booster dose 1 year later. We conducted a 5-year follow-up assessment of the persistence of the immune response the 144 children remaining in this cohort after first booster dose.

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Background: To determine the seroprevalence and transmission dynamics of dengue virus (DENV), age-stratified longitudinal serological surveys were conducted in Bangphae district, Ratchaburi province, Thailand, for 3 years between April 2012 and April 2015.

Methodology: The surveys enrolled 2012 healthy children and adults between 1 and 55 years-of-age, and a longitudinal serosurvey of six repeated bleeds of the same cohort of individuals was conducted every 8 months for the first 2 years (M0, M8, M16) and every half a year (M24, M30, M36) for the rest of the study period. All samples were tested using in-house indirect sandwich dengue IgG ELISA to determine DENV antibody titer, and 640 paired samples which showed rising of DENV IgG titers in paired serum were further tested using in-house neutralization assay, Plaque Reduction Neutralization Test (PRNT50).

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Background: International travel is among the leading impactful factors of COVID-19 transmission; thus, adequate knowledge, good attitude and good preventive practices toward COVID-19 for international travelers are particularly essential for successful pandemic control.

Methods: A cross-sectional, questionnaire-based study was conducted to determine knowledge, attitude and practices (KAP) of international travelers (both Thai and non-Thai) and expatriates in Thailand. The data were collected at the Thai Travel Clinic, Bangkok, Thailand and via online platforms during May to October 2020.

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Background: Vaccines are the main prophylactic measure against pandemic influenza. Adjuvanted, cell culture-derived vaccines, which are not subject to limitations of egg-based vaccine production, have the potential to elicit an antibody response against heterologous strains and may be beneficial in the event of an A/H5N1 pandemic.

Methods: A prespecified exploratory analysis of data from a phase 2, randomized, controlled, observer-blind multicenter trial (NCT01776554) to evaluate the immunogenicity of a MF59-adjuvanted, cell culture-based A/H5N1 influenza vaccine (aH5N1c), containing 7.

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Background: Dengue is a major public health problem in Thailand, but data are often focused on certain dengue-endemic areas. Methods: To better understand dengue epidemiology and clinical characteristics in Thailand, a fever surveillance study was conducted among patients aged 1-55 years, who presented with non-localized febrile illness at Bang Phae Community Hospital in Ratchaburi province, Thailand from October 2011 to September 2016.

Results: Among 951 febrile episodes, 130 were dengue-confirmed.

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Background: Early diagnosis of neonatal sepsis is essential to prevent severe complications and avoid unnecessary use of antibiotics. The mortality of neonatal sepsis is over 18%in many countries. This study aimed to develop a predictive model for the diagnosis of bacterial late-onset neonatal sepsis.

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Background: Dengue is an important mosquito-borne disease. There is currently only one licensed vaccine for dengue prevention. The vaccine provides higher efficacy in pre-vaccination dengue-seropositive persons but a higher risk of subsequent more severe dengue in dengue-seronegative persons.

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Background: A/H5N1 influenza virus has significant pandemic potential, and vaccination is the main prophylactic measure. This phase 2, randomized, observer-blind, multicenter study evaluated the safety and immunogenicity of two MF59-adjuvanted, cell culture-derived H5N1 (aH5N1c) vaccine formulations in healthy pediatric subjects 6 months to 17 years old.

Methods: Subjects (N = 662) received 2 aH5N1c doses 3 weeks apart, containing either 7.

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Background: A/H5N1 influenza viruses have high pandemic potential; consequently, vaccines need to be produced rapidly. MF59® adjuvant reduces the antigen required per dose, allowing for dose sparing and more rapid vaccine availability.

Methods: Two multicenter, phase II trials were conducted to evaluate the safety and immunogenicity of an MF59-adjuvanted, cell culture-derived, A/H5N1 vaccine (aH5N1c) among 979 adult (18-64 years old) and 1393 elderly (≥65 years old) subjects.

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Introduction: Fifteen million people each year receive post-exposure prophylaxis (PEP) to prevent rabies, yet the disease remains neglected and highly under-reported.

Areas Covered: In this systematic literature review, we assessed the immunogenicity, efficacy, and safety of a purified chick embryo cell-culture rabies vaccine (PCECV) for PEP against rabies by intramuscular (IM) or intradermal (ID) administration. We performed meta-analyses to compare immunogenicity according to the route of vaccine administration, study population, and PEP regimen, such as number of doses, and concomitant rabies immunoglobulin.

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Background: This phase III clinical trial compared the immunogenicity and safety of a purified chick-embryo cell rabies vaccine (PCECV) administered according to a shortened post-exposure prophylaxis (PEP) 4-site/1-week intradermal regimen, compared with the currently recommended 2-site/Thai Red Cross (TRC) regimen.

Methodology/principal Findings: This controlled, open-label, multi-center study (NCT02177032) enrolled healthy individuals ≥1 year of age, randomized into 4 groups to receive intradermal PCECV according to one of the 2 regimens, with or without human rabies immunoglobulin (HRIG) administration at first visit (in adults only). Rabies virus neutralizing antibody (RVNA) concentrations and percentages of participants with RVNA concentrations ≥0.

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Background: Co-administration of vaccines in adolescents may improve coverage. We assessed co-administration of quadrivalent meningococcal serogroups A, C, W and Y tetanus toxoid-conjugate vaccine (MenACWY-TT), human papillomavirus 16/18 AS04-adjuvanted vaccine (AS04-HPV16/18) and tetanus-diphtheria-acellular pertussis vaccine (Tdap) in girls and young women.

Methods: In this phase IIIb study (NCT01755689), 1300 healthy 9-25-year-old females were randomized (1:1:1:1:1) to receive: MenACWY-TT at month (M) 0 and AS04-HPV16/18 at M1, M2, M7; MenACWY-TT and AS04-HPV16/18 at M0 and AS04-HPV16/18 at M1, M6; AS04-HPV16/18 at M0, M1, M6; MenACWY-TT, Tdap and AS04-HPV16/18 at M0 and AS04-HPV16/18 at M1, M6; Tdap and AS04-HPV16/18 at M0 and AS04-HPV16/18 at M1, M6.

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Unlabelled: Inactivated mouse-brain-derived Japanese encephalitis vaccine has a worrisome safety profile and the live attenuated vaccine is unsuitable in immunodeficiency. This study aimed to evaluate the immunogenicity and safety of an inactivated chromatographically purified Vero-cell-derived JE vaccine (CVI-JE, Beijing P-3 strain) in children. 152 healthy Thai children, with an average (SD) age of 14.

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Background: Dengue fever is a major public health concern in many parts of the tropics and subtropics. The first dengue vaccine has already been licensed in six countries. Given the growing interests in the effective use of the vaccine, it is critical to understand the economic burden of dengue fever to guide decision-makers in setting health policy priorities.

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Background: The number of Thai tourists visiting India is increasing each year. Most studies investigating health problems among international travellers to India have focused on travellers from Europe or North America, and the applicability of these studies to Asian travellers is unknown.

Methods: This cross-sectional study used data collected from Thai tourists who had recently completed a trip to India.

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Background: An acellular Pertussis (aP) vaccine containing recombinant genetically detoxified Pertussis Toxin (PTgen), Filamentous Hemagglutinin (FHA) and Pertactin (PRN) has been developed by BioNet-Asia (BioNet). We present here the results of the first clinical study of this recombinant aP vaccine formulated alone or in combination with tetanus and diphtheria toxoids (TdaP).

Methods: A phase I/II, observer-blind, randomized controlled trial was conducted at Mahidol University in Bangkok, Thailand in healthy adult volunteers aged 18-35 y.

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Background: Dengue diagnosis confirmation and surveillance are widely based on serological assays to detect anti-dengue IgM or IgG antibodies since such tests are affordable/user-friendly. The World Health Organization identified serological based diagnosis as a potential tool to define probable dengue cases in the context of vaccine trials, while acknowledging that this may have to be interpreted with caution.

Methods: In a phase IIb randomized, placebo-controlled trial assessing the efficacy of a tetravalent dengue vaccine (CYD-TDV) in Thai schoolchildren, case definition was based on virological confirmation by either serotype-specific RT-PCRs or by NS1-antigen ELISA (Clinicaltrials.

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Background: The rise in dengue fever cases and the absence of dengue vaccines will likely cause governments to consider various types of effective means for controlling the disease. Given strong public interests in potential dengue vaccines, it is essential to understand the private economic benefits of dengue vaccines for accelerated introduction of vaccines into the public sector program and private markets of high-risk countries.

Methodology/principal Findings: A contingent valuation study for a hypothetical dengue vaccine was administered to 400 households in a multi-country setting: Vietnam, Thailand, and Colombia.

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This retrospective study was conducted to assess the differences in clinical features between children and adults with dengue hemorrhagic fever/ dengue shock syndrome (DHF/DSS) admitted to Ratchaburi Hospital, Ratchaburi Province, Thailand. A total of 273 patients with DHF/DSS admitted to Ratchaburi Hospital during January 2007 to May 2008 were included in the study. The median age (range) of studied subjects was 16 years (6 months to 62 years) and the ratio of adults to children was 1.

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Background: Commonly used trivalent vaccines contain one influenza B virus lineage and may be ineffective against viruses of the other B lineage. We evaluated the efficacy of a candidate inactivated quadrivalent influenza vaccine (QIV) containing both B lineages.

Methods: In this multinational, phase 3, observer-blinded study, we randomly assigned children 3 to 8 years of age, in a 1:1 ratio, to receive the QIV or a hepatitis A vaccine (control).

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In this study, we compared the immunogenicities of two lots of meningococcal ACWY-tetanus toxoid conjugate vaccine (MenACWY-TT) that differed in serogroup A polysaccharide (PS) O-acetylation levels and evaluated their immunogenicities and safety in comparison to a licensed ACWY polysaccharide vaccine (Men-PS). In this phase III, partially blinded, controlled study, 1,170 healthy subjects aged 18 to 25 years were randomized (1:1:1) to receive one dose of MenACWY-TT lot A (ACWY-A) (68% O-acetylation), MenACWY-TT lot B (ACWY-B) (92% O-acetylation), or Men-PS (82% O-acetylation). Immunogenicity was evaluated in terms of serum bactericidal activity using rabbit complement (i.

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