Risk Factors and Outcomes of Influenza Infection among Children Presenting with Influenza-Like Illness
Warunee Punpanich Vandepitte MD, PhD*,**, Supichaya Netsawang MD***, Piyarat Suntarattiwong MD*,**, Suchada Srisarang MSc**,***, Malinee Chittaganpitch MSc****, Tawee Chotpitayasunondh MD**,***
Affiliation : * Department of Pediatrics, Queen Sirikit National Institute of Child Health, Bangkok, Thailand ** College of Medicine, Rangsit University, Bangkok, Thailand *** Clinical Research Unit, Queen Sirikit National Institute of Child Health, Bangkok, Thailand **** Thailand National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand
Objective : Limited data were available to guide management, counseling, and/or diagnostic investigation among children
presenting with influenza-like illness (ILI). During a recent period of high influenza activity, we wished to determine the
frequency, outcomes, and factors associated with influenza infection among children presenting with ILI.
Material and Method: During September and October 2010, children presenting with ILI were enrolled. Nasal swabs were
sent for polymerase chain reaction (PCR) to determine the frequency and types of influenza. Information of demographic
characteristics, potential risk factors, and short-term outcomes of study participants were collected.
Results : Among 300 enrolled subjects, influenza infections were identified in 170 (56.7%) cases; 45.7% (n = 137) were
influenza A and 11% (n = 33) were influenza B. Most cases recovered uneventfully with a 3.7% (n = 11) hospitalization rate.
Risks for hospitalization did not differ by infection status (2.4% vs. 5.4% between those with and without influenza infection,
respectively) or types of influenza infection. Logistic regression analysis indicated that older age, having a household member
with acute respiratory illness (ARI) during the previous 7 days, having an underlying co-morbidity, and a history of
premature birth were associated with influenza, with adjusted odds ratios and 95% confidence intervals of 1.19 (1.087, 1.30),
3.21 (1.096, 9.424), 2.15 (1.244, 3.728), and 0.08 (0.007, 0.876), respectively.
Conclusion : The outcomes of influenza-associated ILI were generally favourable, with no fatalities and 2.4% risk for
hospitalization. Among children presenting with ILI, age, household contact with ARI, and co morbidities increased the
likelihood of influenza, whereas history of premature birth was negatively associated with influenza.
Keywords : Children, Clinical outcomes, Influenza, Influenza-like illness (ILI), Risk factors
