Fever Responses Are Enhanced with Advancing Age during Respiratory Syncytial Virus Infection among Children under 24 Months Old

Abstract

The most important risk factor for severe respiratory syncytial virus (RSV) infection is considered young age due to the immature immune system. The risk at young age is reported greater for RSV than for other respiratory infectious agents. Based on the strong association between young age and severity of RSV infection due to immature immunity, we aimed to assess whether there were any age-related differences in fever responses, as one clinical aspect of the immune response. In our observational study over two seasons (2014-2015 and 2015-2016), daily body temperatures of children under 3 years old with RSV infection were recorded from the first medical visit during the acute phase to defervescence. The body temperature records were analyzed among 171 children of four age groups (< 6, < 12, < 24 and ≥ 24 months), in terms of fever development, degrees of fever onset, the highest fever during the period, and fever duration. There were 54 patients in the group of < 6 months, 41 in the group of < 12 months, 58 in the group of < 24 months, and 18 in the group of ≥ 24 months. We thus found the correlation between age and fever responses under 24 months old; namely, the more the age advanced, the more frequently high and prolonged fever was experienced. Importantly, infants under 6 months old tend to show the suppressed fever responses. In conclusion, young infants with reduced fever response during RSV infection do not implicate less severity and needs attentive management.

Risk factors associated with severe disease in respiratory syncytial virus infected children under 5 years of age

“…As fever is common in RSV disease, but not pathognomonic ( 6 , 41 , 42 ), this could have led to a somewhat skewed inclusion of patients. However, previous studies do support the presence of fever in most children older than 12 months of age hospitalized for RSV disease ( 43 ).…”

Hospitalization rate of respiratory syncytial virus‐associated acute lower respiratory infection among young children in Suzhou, China, 2010–2014

“…After including fever into the criteria, the hospitalization rate of RSV‐ALRI (with fever) for children aged 0–59 months dropped by 57% to 6 per 1000 children years and by 84% to 11 per 1000 children years for children aged 0–5 months (Figure S1). As confirmed by several studies, case definitions that include fever in RSV surveillance would result in a proportion of missed cases, particularly among young infants 4,5,27 . In this regard, employing broad ALRI inclusion criteria made this study less likely to miss RSV‐infected cases and yield more accurate estimates of RSV‐ALRI hospitalization rates.…”

“…As confirmed by several studies, case definitions that include fever in RSV surveillance would result in a proportion of missed cases, particularly among young infants. 4 , 5 , 27 In this regard, employing broad ALRI inclusion criteria made this study less likely to miss RSV‐infected cases and yield more accurate estimates of RSV‐ALRI hospitalization rates.…”

World Health Organization Influenza-Like Illness Underestimates the Burden of Respiratory Syncytial Virus Infection in Community-Dwelling Older Adults

“…Fever is less frequently reported in RSV infections compared to influenza infections [ 7 , 16–19 ]. Moreover, age might also negatively influence occurrence of fever as shown for newborns [ 8 , 9 , 20 ], but also for the elderly who may lack a robust febrile response in up to one-third of acute infections [ 21 ]. The latter can be caused by a lower baseline temperature (simply not reaching the fever threshold) or because of diminished febrile responses [ 21 ].…”