Publications by authors named "Theodore F Tsai"

Dengue, a mosquitoborne flavivirus infection, is increasingly a disease of older adults who are more likely to have chronic diseases that confer risk for severe outcomes of dengue infection. In a population-based study in Taiwan, adjusted risks for dengue-related hospitalization, intensive care unit admission, and death increased progressively with age.

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The 2017-2018 seasonal influenza epidemics were severe in the US and Australia where the A(H3N2) subtype viruses predominated. Although circulating A(H3N2) viruses did not differ antigenically from that recommended by the WHO for vaccine production, overall interim vaccine effectiveness estimates were below historic averages (33%) for A(H3N2) viruses. The majority (US) or all (Australian) vaccine doses contained multiple amino-acid changes in the hemagglutinin protein, resulting from the necessary adaptation of the virus to embryonated hen's eggs used for most vaccine manufacturing.

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Influenza directly or indirectly contributes to the four leading causes of global mortality, at rates that are highest in older adults. As the proportion of older adults in the Korean population is greater than in most other countries, influenza prevention is a greater public health priority in Korea than elsewhere. Conventional inactivated influenza vaccine (IIV) is less immunogenic and efficacious (-50%) in older than in young adults, but adjuvanting the vaccine with oil-in-water emulsion MF59® increases immunogenicity, resulting in comparatively higher levels of hemagglutination inhibition antibodies and greater protection against all influenza, as well as cases requiring hospitalization.

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Article Synopsis
  • Pregnant women were studied to assess their immune responses to the MF59®-adjuvanted H1N1 vaccine during the 2009 pandemic, comparing them to non-pregnant women.
  • The study, conducted as a controlled clinical trial, involved different dosage groups for both pregnant and non-pregnant participants, with blood samples taken at multiple time points to evaluate immune responses.
  • Results indicated that non-pregnant women had a significantly higher sero-conversion rate to the vaccine compared to pregnant women, suggesting that the immune response in pregnant women may be weaker.
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Influenza vaccine preparations have been administered to humans since the late 1930s, and the diversity of approaches in licensed trivalent seasonal or monovalent pandemic products is unparalleled by vaccines against any other target. These approaches include inactivated whole virus vaccines, detergent or solvent "split" vaccines, subunit vaccines, live attenuated vaccines, adjuvanted vaccines, intramuscular vaccines, intradermal vaccines, intranasal vaccines, egg-produced vaccines and mammalian cell culture-produced vaccines. The challenges of influenza immunization, including multiple co-circulating strains, antigenic change over time, a broad age spectrum of disease, and the threat of pandemics, continue to drive the development of new approaches.

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MF59-adjuvanted seasonal trivalent inactivated (ATIV) vaccine licensed since 1997 and MF59-adjuvanted pandemic H1N1 vaccines have been distributed to approximately 80M persons. Addition of the emulsion adjuvant to inactivated vaccine formulations provides for higher levels of antibody to the viral hemagglutinin (HA) in less responsive older adults, infants and children which, in the case of the pandemic vaccine, allowed only 3.75 µg of the HA to be immunogenic.

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Objective: To update the estimated global incidence of Japanese encephalitis (JE) using recent data for the purpose of guiding prevention and control efforts.

Methods: Thirty-two areas endemic for JE in 24 Asian and Western Pacific countries were sorted into 10 incidence groups on the basis of published data and expert opinion. Population-based surveillance studies using laboratory-confirmed cases were sought for each incidence group by a computerized search of the scientific literature.

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Background: The efficacy of inactivated influenza vaccines is known to be poor in infants and young children.

Methods: We studied the effect of the adjuvant MF59, an oil-in-water emulsion, on the efficacy of trivalent inactivated influenza vaccine (TIV) in 4707 healthy children 6 to less than 72 months of age who had not previously been vaccinated against influenza. The children were randomly assigned to three study groups, each of which received the assigned vaccines in two doses, 28 days apart, during two consecutive influenza seasons.

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Background: A potential association between the new onset of narcolepsy accompanied by cataplexy - a putative autoimmune disorder, and vaccination with an AS03-adjuvanted A(H1N1) pandemic influenza vaccine is under investigation. We sought cases of narcolepsy from the pharmacovigilance database of a pandemic vaccine adjuvanted with another emulsion adjuvant, MF59(®), and a pooled clinical trials database of MF59-adjuvanted and non-adjuvanted influenza vaccine recipients.

Methods: Using 6 narrowly restrictive and 24 broad sleep disturbance-related MedDRA preferred search terms (PT), we analysed spontaneous adverse events (AEs) reports received through July 31, 2010 and adjudicated suspected cases with onset 1 week-3 months after vaccination, against standardized clinical criteria defining narcolepsy.

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A meeting was held at NIBSC, UK in July 2007 to discuss the implications of progress in the use of cell culture systems for the manufacture of vaccines against influenza. Issues discussed included the effect of using eggs and different cell types in strain selection, development of seed viruses to be used in production and the nature of the reagents to be used in determining vaccine potency. Future studies to progress the field were reviewed.

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The contribution of memory responses after meningococcal vaccination to protection may depend on the rapidity of the response. Toddlers were challenged with a licensed polysaccharide (PS) vaccine 1 year after vaccination with a single dose of meningococcal group C-CRM(197) conjugate (MCC) vaccine at the age of 12 to 15 months. Bactericidal antibodies and immunoglobulin G (IgG) antibodies detected by an enzyme-linked immunosorbent assay (ELISA) were measured before challenge and 4, 7, 14, or 21 Days later ("Days" refer to treatment groups, "days" to sampling days).

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In a retrospective, population-based study, we estimated the age-specific incidence of invasive pneumococcal disease in Hong Kong between 1995 and 2004. The incidence rates per 100,000 were 18.3 (95% confidence interval [CI], 13.

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We evaluated a combination respiratory syncytial virus (RSV) and parainfluenza 3 virus (PIV3) live, attenuated intranasal vaccine for safety, viral replication, and immunogenicity in doubly seronegative children 6-18 months old. RSV cpts-248/404 and PIV3-cp45 vaccines were combined in a dose of 10(5) plaque-forming units of each per 0.5-mL dose and compared with monovalent vaccines or placebo.

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A phase 2 evaluation of live attenuated parainfluenza type 3 (PIV3)-cold passage mutant 45 (cp45) vaccine was conducted in 380 children 6-18 months old; 226 children (59%) were seronegative for PIV3. Of the 226 seronegative children, 114 received PIV3-cp45 vaccine, and 112 received placebo. No significant difference in the occurrence of adverse events (i.

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In 1998, the Centers for Disease Control and Prevention was notified of severe illnesses and one death, temporally associated with yellow fever (YF) vaccination, in two elderly U.S. residents.

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