Pandemic influenza (H1N1) 2009 of pediatric patients at Thammasat University Hospital.

BACKGROUND

An emerge of pandemic influenza H1N1 2009 has devastated the global community. Pediatric population is among the groups with high attack rate.

OBJECTIVE

To study the clinical presentation of pediatric patients (0-15 years old) infected with influenza H1N1 2009 and to evaluate the sensitivity and specificity of the rapid influenza test.

MATERIAL AND METHOD: Retrospective data was collected from the medical reports of patients presenting with influenza like illness (ILI) whose samples from nasal swab were tested for H1N1 using reverse transcription polymerase chain reaction (RT-PCR) during June-September 2009 at the Thammasat University Hospital.

RESULTS

Of 68 patients, 26 were confirmed to have H1N1 2009 strain. Of these, 61.5% were older than 5 years old; 26.9% had underlying conditions and 38.4% had hospitalization. All 26 patients presented with fever and cough; 73% had coryza; 57.6% had sore throat; and 88.4% had injected throat. Six patients (23%) had pneumonia. Patients younger than 5 years old experienced dyspnea and had abnormal results of a chest radiograph significantly more often than patients older than 5. Patients with H1N1 2009 strain were more likely to have sore throat, myalgia, and injected throat than non H1N1 2009 group. However chest wall retraction and abnormal chest radiograph were found significantly less often in the H1N1 group compared to the non-H1N1. No death case was reported. The rapid influenza test was found to have sensitivity of 80%, specificity of 64%, positive predictive value of 74.5%, and negative predictive value of 84.3% when compared to RT-PCR method.

CONCLUSION

During pandemic period, older children with influenza like illness had novel H1N1 2009 infection more than younger children. The majority of pediatric patients presented with mild symptoms. Patients aged below 5 years more frequently experienced pneumonia. The rapid influenza test showed a high sensitivity but low specificity.