Risk factors and patterns of household clusters of respiratory viruses in rural Nepal

Scott, E. M.; Magaret, A.; Kuypers, J.; Tielsch, J. M.; Katz, J.; Khatry, S. K.; Stewart, L.; Shrestha, L.; LeClerq, S. C.; Englund, J. A.; Chu, H. Y.

A total of 825 virus-positive initial illness episodes occurred within 362 households with a median of one (range 0-10) illness episode per household. In the 14 days following initial household illness, 110 subsequent illness episodes occurred, 88 (80%) of which were screened by PCR and 22 (20%) illnesses that did not have a swab collected despite meeting symptom criteria. Eight per cent of illness episodes resulted in a PCR-confirmed secondary case within the household with a total of 79 transmission events in 68 household illness episodes. Household illness clusters occurred in 58 households as some households experienced multiple illness clusters. The incidence of a PCR-confirmed transmission event of any virus occurring in the 14 days following initial Fig. 3 ). HRV coinfection with another respiratory virus had more frequent transmissions (16.1% of HRV coinfections resulted in transmission) compared to monoinfection of HRV (5.8%), coronavirus (3.5%) and RSV (6.7%) (Fig. 2 , see Table 3 for statistical testing).