RESUMO
The World Health Organization selects influenza vaccine compositions biannually to cater to peaks in temperate regions. In tropical and subtropical regions, where influenza seasonality varies and epidemics can occur year-round, the choice of vaccine remains uncertain. Our 17-year molecular epidemiologic survey showed that most influenza A(H3N2) (9/11) and B (6/7) vaccine strains had circulated in East Asia >1 year before inclusion into vaccines. Northern Hemisphere vaccine strains and circulating strains in East Asia were closely matched in 7 (20.6%) of 34 seasons for H3N2 and 5 (14.7%) of 34 seasons for B. Southern Hemisphere vaccines also had a low probability of matching (H3N2, 14.7%; B, 11.1%). Strain drift among seasons was common (H3N2, 41.2%; B, 35.3%), and biannual vaccination strategy (Northern Hemisphere vaccines in November followed by Southern Hemisphere vaccines in May) did not improve matching. East Asia is an important contributor to influenza surveillance but often has mismatch between vaccine and contemporarily circulating strains.
Assuntos
Alphainfluenzavirus/genética , Betainfluenzavirus/genética , Variação Genética , Vacinas contra Influenza/genética , Influenza Humana/epidemiologia , Influenza Humana/virologia , Estações do Ano , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , História do Século XX , História do Século XXI , Hong Kong/epidemiologia , Humanos , Vacinas contra Influenza/imunologia , Influenza Humana/história , Influenza Humana/prevenção & controle , Alphainfluenzavirus/classificação , Alphainfluenzavirus/imunologia , Betainfluenzavirus/classificação , Betainfluenzavirus/imunologia , Epidemiologia Molecular , Filogenia , RNA Viral , Estudos RetrospectivosRESUMO
Norovirus GII.4 Sydney 2012 has spread globally since late 2012. We report hospitalization of patients infected with this strain skewed toward infants and young children among 174 cases during August 2012-July 2013 in Hong Kong, China. This group had higher fecal viral load (≈10-fold) than did older children and adults.
Assuntos
Infecções por Caliciviridae/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Fezes/virologia , Hong Kong/epidemiologia , Hospitalização , Humanos , Lactente , Recém-Nascido , Pessoa de Meia-Idade , Norovirus/genética , Norovirus/isolamento & purificação , Estudos Prospectivos , Adulto JovemRESUMO
BACKGROUND: The epidemiology of human parechovirus (HPeV) in Asia remains obscure. We elucidated the prevalence, seasonality, type distribution and clinical presentation of HPeV among children in Hong Kong. METHODS: A 24-month prospective study to detect HPeV in children ≤36 months hospitalized for acute viral illnesses. RESULTS: 2.3% of the 3911 children examined had HPeV infection, with most (87.5%) concentrated in September-January (autumn-winter). 81.3% were HPeV1 and 12.5% were HPeV4, while HPeV3 was rare (2.5%). HPeV was a probable cause of the disease in 47.7% (42/88), mostly self-limiting including acute gastroenteritis, upper respiratory tract infection and maculopapular rash. A neonate developed severe sepsis-like illness with HPeV3 as the only pathogen detected. A high proportion (60.0%) of children coinfected with HPeV and other respiratory virus(es) had acute bronchiolitis or pneumonia. Six children with HPeV coinfections developed convulsion / pallid attack. Most rash illnesses exhibited a generalized maculopapular pattern involving the trunk and limbs, and were more likely associated with HPeV4 compared to other syndrome groups (36.4% vs. 3.1%, p = 0.011). CONCLUSIONS: In Hong Kong, HPeV exhibits a clear seasonality (autumn-winter) and was found in a small proportion (2.3%) of young children (≤36 months) admitted with features of acute viral illnesses. The clinical presentation ranged from mild gastroenteritis, upper respiratory tract infection and febrile rash to convulsion and severe sepsis-like illness. HPeV3, which is reported to associate with more severe disease in neonates, is rare in Hong Kong. HPeV coinfection might associate with convulsion and aggravate other respiratory tract infections.
Assuntos
Parechovirus , Infecções por Picornaviridae/epidemiologia , Infecções por Picornaviridae/virologia , Estações do Ano , Clima Tropical , Pré-Escolar , Diarreia/epidemiologia , Diarreia/virologia , Fezes/virologia , Feminino , Gastroenterite/epidemiologia , Gastroenterite/virologia , Hong Kong/epidemiologia , Hospitalização , Humanos , Lactente , Recém-Nascido , Masculino , Parechovirus/classificação , Parechovirus/genética , Filogenia , Estudos Prospectivos , RNA Viral , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/virologiaRESUMO
We conducted a 2-year hospital-based study on norovirus gastroenteritis among children and adults between August 2012 and September 2014. A total of 1,146 norovirus cases were identified. Young children (aged ≤ 5 years) accounted for a majority (53.3%) of cases. Hospitalization incidence exhibited a U-shaped pattern with the highest rate in young children (1,475 per 100,000 person-years), followed by the elderly aged > 84 years (581 per 100,000 person-years). A subset (n = 395, 34.5%) of cases were selected for norovirus genotyping and noroviral load measurement. Non-GII.4 infections were more commonly observed in young children than in older adults (aged > 65 years) (20.5% versus 9.2%; p < 0.05). In young children, the median noroviral load of GII.4 and non-GII.4 cases was indistinguishably high (cycle threshold value, median [interquartile range]: 16.6 [15.2-19.3] versus 16.6 [14.9-21.6]; p = 0.45). Two age-specific non-GII.4 genotypes (GII.3 and GII.6) were identified among young children. These findings may have implications in norovirus vaccination strategy.