Frequent Respiratory Viral Infections in Children with Febrile Neutropenia - A Prospective Follow-Up Study

Söderman, Martina; Rhedin, Samuel; Tolfvenstam, Thomas; Rotzén-Östlund, Maria; Albert, Jan; Broliden, Kristina; Lindblom, Anna

Respiratory viruses and their shedding times have not been thoroughly investigated in immunosuppressed children. Earlier studies on RSV have shown prolonged viral shedding in immunosuppressed children compared with healthy children [32] . Martin et al. conducted a longitudinal study of healthy immunocompetent children attending a daycare center [33] and found prolonged shedding (i.e., persistent virus >7 days) of all viruses examined except Flu A and B. Jartti et al. reported shedding times of 2-3 and 5-6 weeks for EV and RV, respectively, in immunocompetent children [17] . However, RV was not sequenced in that study; therefore, it is unclear whether the sample at 5 weeks represented the same or a new genotype of RV. Another study reported that prolonged persistence (>30 days) of the same RV strain is uncommon (<5%) [34] . Shedding times were of special interest in our cohort of immunosuppressed children because viral shedding necessitates isolation from other immunosuppressed children. The design of our present study did not allow us to determine the exact shedding time, which is a major limitation. However, the clearance of all viruses except RV-A and HCoV at a median follow-up time of 28 days, together with respiratory symptoms appearing at the time of fever onset in a majority of the patients, suggests that the shedding time for viruses such as Flu, HMPV, RSV and PIV is limited. The same RV genotypes were detected from follow-up samples in four episodes, with a follow-up time of 12-51 days. Furthermore, five patients positive for RV reported symptom appearance 6 days or longer before fever onset. That could indicate longer shedding times for RV, which is in line with results from studies on immunocompetent children [17] . However, this needs to be addressed in additional studies with repeated followup sampling, preferable on a weekly basis.