ABSTRACT.Objective. In 1998, an enterovirus 71 (EV71) epidemic in Taiwan was associated with hand, foot, and mouth disease (HFMD)/herpangina and involved 78 fatal cases. We measured EV71 seroprevalence rates before and after the epidemic and investigated risk factors associated with EV71 infection and illness.Methods. Neutralizing antibodies to EV71 were assayed for 539 people before the epidemic and 4619 people of similar ages after the epidemic. Questionnaires, which were completed during household interviews after the epidemic, solicited demographic variables, exposure history, and clinical manifestations.Results. A total of 129 106 cases of HFMD were reported during the epidemic. Age-specific pre-epidemic EV71 seroprevalence rates were inversely related to agespecific periepidemic mortality rates (r ؍ ؊0.82) or severe case rates (r ؍ ؊0.93). Higher postepidemic EV71 seropositive rates among children who were younger than 3 years positively correlated with higher mortality rates in different areas (r ؍ 0.88). After the epidemic, 51 (56%) of 91 younger siblings of elder siblings who were EV71-seropositive were EV71-seropositive; otherwise, 2.2% (4 of 186) of younger siblings were EV71-seropositive (matched odds ratio [OR]: 10; 95% confidence interval [CI]: 3.4 -29). Stepwise multiple logistic regression revealed other factors associated with EV71 infection to be older age (adjusted OR: 2.5; 95% CI: 1.9 -3.4), attendance at kindergartens/child care centers (adjusted OR: 1.8; 95% CI: 1.3-2.5), contact with HFMD/herpangina (adjusted OR: 1.6; 95% CI: 1.2-2.1), greater number of children in a family (adjusted OR: 1.4; 95% CI: 1.1-1.7), and rural residence (adjusted OR: 1.4; 95% CI: 1.2-1.6). Twenty-nine percent of preschool children who were infected with EV71 developed HFMD/herpangina. Younger age and contact with HFMD/herpangina were significant factors for the development of EV71-related HFMD/herpangina in these children.Conclusions. An increased incidence of EV71 infection in young children occurred more often in geographic areas with increased mortality rates. Intrafamilial and kindergarten transmissions among preschool children were major modes of disease transmission during the widespread EV71 epidemic in Taiwan in 1998. Pediatrics 2002;109(6). URL: http://www.pediatrics.org/cgi/content/ full/109/6/e88; enterovirus 71; hand, foot, and mouth disease; seroprevalence; transmission; risk factors; symptomatic ratio; reemerging infectious disease; Taiwan.ABBREVIATIONS. EV71, enterovirus 71; HFMD, hand, foot, and mouth disease; OR, odds ratio; CI, confidence interval; SD, standard deviation. E nterovirus 71 (EV71) has been associated with outbreaks in the United States, Europe, Australia, Japan, Brazil, and Malaysia 1-10 since it was originally recognized in l969 in California. 1 Before 1998, 3 large outbreaks with dozens of fatal cases occurred in Bulgaria in 1975, Hungary in 1978, and Malaysia in 1997 However, few studies have investigated the mode of transmission, the protective effect of preexisting EV71...
Real-time reverse transcription (RT)-PCR is currently the most sensitive method to detect severe acute respiratory syndrome coronavirus 2 virus (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19). However, the correlation between detectable viral RNA and culturable virus in clinical specimens remains unclear. Here, we performed virus culture for 60 specimens that were confirmed to be positive for SARS-CoV-2 RNA by real-time RT-PCR. The virus could be successfully isolated from 12 throat and nine nasopharyngeal swabs, and two from sputum specimens. The lowest copy number required for virus isolation was determined to be 5.4, 6.0, and 5.7 log10 genome copies/mL sample for detecting the nsp12, E, and N gene, respectively. We further examined the correlation of genome copy number and virus isolation in different regions of the viral genome, demonstrating that culturable specimens are characterized by high copy numbers with a linear correlation observed between copy numbers of amplicons targeting structural and non-structural regions. Overall, these results indicate that in addition to the copy number, the integrity of the viral genome should be considered when evaluating the infectivity of clinical SARS-CoV-2 specimens.
The COVID-19 pandemic is a worldwide health emergency which calls for an unprecedented race for vaccines and treatment. In developing a COVID-19 vaccine, we applied technology previously used for MERS-CoV to produce a prefusion-stabilized SARS-CoV-2 spike protein, S-2P. To enhance immunogenicity and mitigate the potential vaccine-induced immunopathology, CpG 1018, a Th1-biasing synthetic toll-like receptor 9 (TLR9) agonist was selected as an adjuvant candidate. S-2P in combination with CpG 1018 and aluminum hydroxide (alum) was found to be the most potent immunogen and induced high titer of neutralizing antibodies in sera of immunized mice against pseudotyped lentivirus reporter or live wild-type SARS-CoV-2. In addition, the antibodies elicited were able to cross-neutralize pseudovirus containing the spike protein of the D614G variant, indicating the potential for broad spectrum protection. A marked Th1 dominant response was noted from cytokines secreted by splenocytes of mice immunized with CpG 1018 and alum. No vaccine-related serious adverse effects were found in the dose-ranging study in rats administered single- or two-dose regimens of S-2P combined with CpG 1018 alone or CpG 1018 with alum. These data support continued development of CHO-derived S-2P formulated with CpG 1018 and alum as a candidate vaccine to prevent COVID-19 disease.
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