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The source of respiratory syncytial virus infection in infants: a household cohort study in rural Kenya.

Munywoki PK, Koech DC, Agoti CN, Lewa C, Cane PA, Medley GF, Nokes DJ - J. Infect. Dis. (2013)

Bottom Line: Households with a child born after the preceding RSV epidemic and ≥ 1 elder sibling were recruited.RSV was detected in 37 households (84%) and 173 participants (38%) and 28 study infants (64%).The infants acquired infection from within (15 infants; 54%) or outside (9 infants; 32%) the household; in 4 households the source of infant infection was inconclusive.

View Article: PubMed Central - PubMed

Affiliation: KEMRI- Wellcome Trust Research Programme, Kilifi, Kenya.

ABSTRACT

Background: Respiratory syncytial virus (RSV) vaccine development for direct protection of young infants faces substantial obstacles. Assessing the potential of indirect protection using different strategies, such as targeting older children or mothers, requires knowledge of the source of infection to the infants.

Methods: We undertook a prospective study in rural Kenya. Households with a child born after the preceding RSV epidemic and ≥ 1 elder sibling were recruited. Nasopharyngeal swab samples were collected every 3-4 days irrespective of symptoms from all household members throughout the RSV season of 2009-2010 and tested for RSV using molecular techniques.

Results: From 451 participants in 44 households a total of 15 396 nasopharyngeal swab samples were samples were collected, representing 86% of planned sampling. RSV was detected in 37 households (84%) and 173 participants (38%) and 28 study infants (64%). The infants acquired infection from within (15 infants; 54%) or outside (9 infants; 32%) the household; in 4 households the source of infant infection was inconclusive. Older children were index case patients for 11 (73%) of the within-household infant infections, and 10 of these 11 children were attending school.

Conclusion: We demonstrate that school-going siblings frequently introduce RSV into households, leading to infection in infants.

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Related in: MedlinePlus

Distribution of primary cases for the 28 household episodes linked with the study infant infection in rural Kenya. Only the first household episodes/outbreaks involving the study infants are shown. The diagonal and zigzag lines shading the circles indicate outside- and within-household acquisition of the infant infections, respectively, and the area of the circle is in proportion to the number of cases in each category.
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JIT828F2: Distribution of primary cases for the 28 household episodes linked with the study infant infection in rural Kenya. Only the first household episodes/outbreaks involving the study infants are shown. The diagonal and zigzag lines shading the circles indicate outside- and within-household acquisition of the infant infections, respectively, and the area of the circle is in proportion to the number of cases in each category.

Mentions: Of the 73 separate household episodes identified, 37 (50.7%) resulted in the infection of the study infants. Overall, 28 of the 44 study infants (63.6%) were infected: 21 had 1 episode, 5 had 2, and 2 had 3 episodes. The 28 infant infections that were first episodes were associated with an outbreak in 24 households (85.7%). Subsequent results for the infant infections are limited to these first episodes. The results for all infant episodes are shown in Supplementary Figure 1. Based on the temporal pattern of infections in each household, 15 (53.6%) of the 28 study infant infections were acquired through transmission within households, and 9 (32.1%) were acquired from outside the household. The source of infant infections in the remaining 4 households (14.3%) was inconclusive because the household episodes had a sibling and the infant as coprimary case patients (Figure 2).Figure 2.


The source of respiratory syncytial virus infection in infants: a household cohort study in rural Kenya.

Munywoki PK, Koech DC, Agoti CN, Lewa C, Cane PA, Medley GF, Nokes DJ - J. Infect. Dis. (2013)

Distribution of primary cases for the 28 household episodes linked with the study infant infection in rural Kenya. Only the first household episodes/outbreaks involving the study infants are shown. The diagonal and zigzag lines shading the circles indicate outside- and within-household acquisition of the infant infections, respectively, and the area of the circle is in proportion to the number of cases in each category.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4017365&req=5

JIT828F2: Distribution of primary cases for the 28 household episodes linked with the study infant infection in rural Kenya. Only the first household episodes/outbreaks involving the study infants are shown. The diagonal and zigzag lines shading the circles indicate outside- and within-household acquisition of the infant infections, respectively, and the area of the circle is in proportion to the number of cases in each category.
Mentions: Of the 73 separate household episodes identified, 37 (50.7%) resulted in the infection of the study infants. Overall, 28 of the 44 study infants (63.6%) were infected: 21 had 1 episode, 5 had 2, and 2 had 3 episodes. The 28 infant infections that were first episodes were associated with an outbreak in 24 households (85.7%). Subsequent results for the infant infections are limited to these first episodes. The results for all infant episodes are shown in Supplementary Figure 1. Based on the temporal pattern of infections in each household, 15 (53.6%) of the 28 study infant infections were acquired through transmission within households, and 9 (32.1%) were acquired from outside the household. The source of infant infections in the remaining 4 households (14.3%) was inconclusive because the household episodes had a sibling and the infant as coprimary case patients (Figure 2).Figure 2.

Bottom Line: Households with a child born after the preceding RSV epidemic and ≥ 1 elder sibling were recruited.RSV was detected in 37 households (84%) and 173 participants (38%) and 28 study infants (64%).The infants acquired infection from within (15 infants; 54%) or outside (9 infants; 32%) the household; in 4 households the source of infant infection was inconclusive.

View Article: PubMed Central - PubMed

Affiliation: KEMRI- Wellcome Trust Research Programme, Kilifi, Kenya.

ABSTRACT

Background: Respiratory syncytial virus (RSV) vaccine development for direct protection of young infants faces substantial obstacles. Assessing the potential of indirect protection using different strategies, such as targeting older children or mothers, requires knowledge of the source of infection to the infants.

Methods: We undertook a prospective study in rural Kenya. Households with a child born after the preceding RSV epidemic and ≥ 1 elder sibling were recruited. Nasopharyngeal swab samples were collected every 3-4 days irrespective of symptoms from all household members throughout the RSV season of 2009-2010 and tested for RSV using molecular techniques.

Results: From 451 participants in 44 households a total of 15 396 nasopharyngeal swab samples were samples were collected, representing 86% of planned sampling. RSV was detected in 37 households (84%) and 173 participants (38%) and 28 study infants (64%). The infants acquired infection from within (15 infants; 54%) or outside (9 infants; 32%) the household; in 4 households the source of infant infection was inconclusive. Older children were index case patients for 11 (73%) of the within-household infant infections, and 10 of these 11 children were attending school.

Conclusion: We demonstrate that school-going siblings frequently introduce RSV into households, leading to infection in infants.

Show MeSH
Related in: MedlinePlus