Transmission Dynamics of Respiratory Syncytial Virus within the Household and in the Community

Okiro, Emelda Aluoch (2007). Transmission Dynamics of Respiratory Syncytial Virus within the Household and in the Community. PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000ea3a

Abstract

Introduction: Knowledge on RSV infection and disease is sparse in much of sub-Saharan Africa. Disease incidence is highest in infants, but there is little understanding on how and where they become infected. Characteristics of RSV transmission are poorly defined. Understanding transmission of RSV within the community is important in understanding infection and disease in infants and in defining potential effects of vaccination

Methods: A prospective longitudinal surveillance of ARI in a random selection of households in Kilifi District, coastal Kenya, was established in early 2003, and continued until 2005. Participants were under active and passive surveillance and were reviewed using a standard proforma. Nasal washings from symptomatic household members were screened for RSV antigen using IFAT. Oral-fluid for serological determination of infection was collected at enrolment and every 3 months.

Results: 81 households were recruited, 25 were lost to followup. 121 infections were identified approximately half of which were re-infections. The virus infected 54% of the households. Incidence of RSV infection was 218 cases/1000 cyo (95% CI, 182- 264). The incidence of primary infection was 476 cases/1000 cyo (95% CI, 361-630) and re-infection was 147/1000 cyo (95% CI, 115-189). Risk of disease was higher during primary infection than re-infection with the highest risk of disease in children 12-17months old. Estimated duration of viral shedding was short, <1 week. Age, sex, infection history and severity of infection were not found to significantly affect duration of shedding. Pre-school children with siblings in school had higher rates of infection. Index to secondary case interval was shorter for younger children and SARs were higher in smaller households. Crowding and stunting were associated with increased risk of both LRTI and RSV specific LRTI. Sanitation, type of house, and having siblings under the age of 6 years of age were associated with increased risk of RSV-disease.

Conclusion: We have defined several aspects of RSV transmission and demonstrated an important burden of RSV infection and disease in a rural Kenyan community addressing a need for more information from developing countries.