RESUMO
We studied the transmission of norovirus infection in households in Quininde, Ecuador. Among household contacts of norovirus positive children with diarrhea, norovirus negative children with diarrhea and asymptomatic controls, infection attack rates were 33%, 8% and 18%, respectively (N = 45, 36, 83). Infection attack rates were higher when index children had a higher viral load.
Assuntos
Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/transmissão , Características da Família , Gastroenterite/epidemiologia , Gastroenterite/virologia , Norovirus/isolamento & purificação , Adolescente , Criança , Pré-Escolar , Equador/epidemiologia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Carga ViralRESUMO
BACKGROUND: Although norovirus is the most common cause of gastroenteritis, there are few data on the community incidence of infection/disease or the patterns of acquired immunity or innate resistance to norovirus. METHODS: We followed a community-based birth cohort of 194 children in Ecuador with the aim to estimate (1) the incidence of norovirus gastroenteritis from birth to age 3 years, (2) the protective effect of norovirus infection against subsequent infection/disease, and (3) the association of infection and disease with FUT2 secretor status. RESULTS: Over the 3-year period, we detected a mean of 2.26 diarrheal episodes per child (range, 0-12 episodes). Norovirus was detected in 260 samples (18%) but was not found more frequently in diarrheal samples (79 of 438 [18%]), compared with diarrhea-free samples (181 of 1016 [18%]; P = .919). A total of 66% of children had at least 1 norovirus infection during the first 3 years of life, and 40% of children had 2 infections. Previous norovirus infections were not associated with the risk of subsequent infection. All genogroup II, genotype 4 (GII.4) infections were among secretor-positive children (P < .001), but higher rates of non-GII.4 infections were found in secretor-negative children (relative risk, 0.56; P = .029). CONCLUSIONS: GII.4 infections were uniquely detected in secretor-positive children, while non-GII.4 infections were more often found in secretor-negative children.
Assuntos
Infecções por Caliciviridae/genética , Infecções por Caliciviridae/virologia , Fucosiltransferases/genética , Gastroenterite/genética , Gastroenterite/virologia , Norovirus/genética , Infecções por Caliciviridae/epidemiologia , Pré-Escolar , Estudos de Coortes , Diarreia/epidemiologia , Diarreia/virologia , Equador/epidemiologia , Fezes/virologia , Gastroenterite/epidemiologia , Predisposição Genética para Doença/genética , Genótipo , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Norovirus/imunologia , Norovirus/isolamento & purificação , Saliva/química , Galactosídeo 2-alfa-L-FucosiltransferaseRESUMO
BACKGROUND: We studied the transmission of rotavirus infection in households in peri-urban Ecuador in the vaccination era. METHODS: Stool samples were collected from household contacts of child rotavirus cases, diarrhea controls and healthy controls following presentation of the index child to health facilities. Rotavirus infection status of contacts was determined by RT-qPCR. We examined factors associated with transmissibility (index-case characteristics) and susceptibility (household-contact characteristics). RESULTS: Amongst cases, diarrhea controls and healthy control household contacts, infection attack rates (iAR) were 55%, 8% and 2%, (nâ=â137, 130, 137) respectively. iARs were higher from index cases with vomiting, and amongst siblings. Disease ARs were higher when the index child was <18 months and had vomiting, with household contact <10 years and those sharing a room with the index case being more susceptible. We found no evidence of asymptomatic infections leading to disease transmission. CONCLUSION: Transmission rates of rotavirus are high in households with an infected child, while background infections are rare. We have identified factors associated with transmission (vomiting/young age of index case) and susceptibility (young age/sharing a room/being a sibling of the index case). Vaccination may lead to indirect benefits by averting episodes or reducing symptoms in vaccinees.
Assuntos
Características da Família , Infecções por Rotavirus/prevenção & controle , Infecções por Rotavirus/transmissão , Vacinas contra Rotavirus/imunologia , Rotavirus/imunologia , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , Diarreia/prevenção & controle , Diarreia/virologia , Equador , Feminino , Genótipo , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Razão de Chances , Rotavirus/genética , Infecções por Rotavirus/epidemiologia , Estações do Ano , Vacinação , Adulto JovemRESUMO
OBJECTIVE: To evaluate the duration of protection of pentavaent rotavirus vaccine (RV5) against rotavirus hospitalizations in Nicaragua, a developing country in Central America. METHODS: We conducted a case-control study at 4 hospitals from 2007 through 2010, including 1016 children hospitalized with laboratory-confirmed rotavirus diarrhea, 4930 controls with nonrotavirus diarrhea (ie, "test-negative"), and 5627 controls without diarrhea. All cases and controls were aged ≥ 6 months and born after August 2006. Outcomes included odds of antecedent vaccination between case-patients and controls, and effectiveness of vaccination (1 - adjusted odds ratio [OR] × 100). Duration of protection was assessed by comparing effectiveness among children aged <1 year compared with ≥ 1 year. RESULTS: Indicators of socioeconomic conditions and nonrotavirus vaccination (oral polio vaccine and diphtheria/tetanus/pertussis/hepatitis A/hepatitis B) for test-negative controls were more comparable to the rotavirus case-patients than nondiarrhea controls. RV5 vaccination was associated with a significantly lower risk of rotavirus hospitalization by using test-negative controls (OR: 0.55; 95% confidence interval [CI]: 0.41-0.74) and nondiarrhea controls (OR: 0.30; 95% CI: 0.22-0.40). Risk of rotavirus hospitalization was twofold lower among RV5 vaccinated children aged <1 year (OR: 0.36; 95% CI: 0.22-0.57) compared with RV5 vaccinated children aged ≥ 1 year (OR: 0.70; 95% CI: 0.47-1.05). CONCLUSIONS: RV5 provided good protection against severe rotavirus disease in Nicaragua during the first year of life, when most severe and fatal rotavirus disease in developing countries occurs. However, the decline in protection with age warrants monitoring of disease among older children and consideration of a booster dose evaluation at the end of infancy.
Assuntos
Anticorpos Antivirais/sangue , Países em Desenvolvimento , Diarreia Infantil/imunologia , Diarreia Infantil/prevenção & controle , Infecções por Rotavirus/imunologia , Infecções por Rotavirus/prevenção & controle , Vacinas contra Rotavirus/imunologia , Rotavirus/imunologia , Estudos de Casos e Controles , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Imunização Secundária , Lactente , Masculino , Nicarágua , Razão de Chances , Vigilância da População , Resultado do Tratamento , Vacinas Atenuadas/imunologiaRESUMO
BACKGROUND: In 2006, Brazil began routine immunization of infants <15 wk of age with a single-strain rotavirus vaccine. We evaluated whether the rotavirus vaccination program was associated with declines in childhood diarrhea deaths and hospital admissions by monitoring disease trends before and after vaccine introduction in all five regions of Brazil with varying disease burden and distinct socioeconomic and health indicators. METHODS AND FINDINGS: National data were analyzed with an interrupted time-series analysis that used diarrhea-related mortality or hospitalization rates as the main outcomes. Monthly mortality and admission rates estimated for the years after rotavirus vaccination (2007-2009) were compared with expected rates calculated from pre-vaccine years (2002-2005), adjusting for secular and seasonal trends. During the three years following rotavirus vaccination in Brazil, rates for diarrhea-related mortality and admissions among children <5 y of age were 22% (95% confidence interval 6%-44%) and 17% (95% confidence interval 5%-27%) lower than expected, respectively. A cumulative total of ~1,500 fewer diarrhea deaths and 130,000 fewer admissions were observed among children <5 y during the three years after rotavirus vaccination. The largest reductions in deaths (22%-28%) and admissions (21%-25%) were among children younger than 2 y, who had the highest rates of vaccination. In contrast, lower reductions in deaths (4%) and admissions (7%) were noted among children two years of age and older, who were not age-eligible for vaccination during the study period. CONCLUSIONS: After the introduction of rotavirus vaccination for infants, significant declines for three full years were observed in under-5-y diarrhea-related mortality and hospital admissions for diarrhea in Brazil. The largest reductions in diarrhea-related mortality and hospital admissions for diarrhea were among children younger than 2 y, who were eligible for vaccination as infants, which suggests that the reduced diarrhea burden in this age group was associated with introduction of the rotavirus vaccine. These real-world data are consistent with evidence obtained from clinical trials and strengthen the evidence base for the introduction of rotavirus vaccination as an effective measure for controlling severe and fatal childhood diarrhea.