Respiratory Syncytial Virus (RSV) is a major cause of acute respiratory tract infection among children. It is documented that by age of three years, virtually all children are infected by RSV, and re-infection occurs throughout life [1]. The World Health Organization (WHO) estimates global RSV burden as 64 million cases and about 160,000 deaths annually [2]. The clinical presentation of RSV and influenza is similar, but the antiviral treatment is different. This study aimed to detect the positivity for RSV in hospitalized children (≤2 years) suspected of influenza-A (H1N1) pdm 09 infection during the 2009 influenza pandemic.

The samples (throat swab, nasopharyngeal swab or lung aspirates) were referred to Virus Research and Diagnostic Laboratory of Regional Medical Research Centre for Tribals, Jabalpur, India following the Government of India guidelines [3]. A total of 2549 samples (Oct 2009-Dec 2012) consisting of 398 (16%) samples of age group ≤2 years were received and processed for diagnosis of influenza by WHO recommended qRT-PCR [4]. Part of the samples was stored at -70ºC. From the aforesaid age group, 54 (14%) samples were found to be positive for Influenza A. From remaining 344 samples, 75 cases were randomly selected for RSV testing. Viral RNA extraction was done (Qiagen, Germany) followed by RT-PCR as described by Stockton, et al. [5] with minor modifications. The study was approved by our Centre’s ethical committee.

Table I  Distribution of RSV Cases By Age

Out of 75 samples, 33 (44%) were positive for RSV, of which 25 (76%) and 8 (24%) were positive for RSV-A and RSV-B, respectively (Table I). There was no significant difference observed in clinical features (fever, cough, sore throat, nasal catarrh, shortness of breath, and pneumonia and/or pneumonia like symptoms) of RSV and Influenza. Studies from developing countries have reported that RSV is responsible for 27-96% of hospitalized cases of acute respiratory tract infections, and it has higher positivity than any other respiratory virus in pediatric age group [6-8]. When RSV positivity was compared with contemporary Influenza A positivity, the children (≤2 years) were at significantly higher risk of RSV (p<0.001). During the recent Influenza A (H1N1) pdm09 pandemic, majority of severe cases with influenza like illness might have been labelled and treated for influenza, though most of the children (≤2 years) probably had RSV infection. Oseltamivir that was used as a frontline antiviral drug for Influenza A (H1N1) pdm09 has known psychological and neuropsychiatric side-effects in children, and has also been shown to prolong RSV shedding [9]. We suggest that samples from age group ≤2 years in children with influenza like illness should be tested simultaneously for RSV in order to rationalize antiviral treatment.