This study evaluated the overall impact of human metapneumovirus (hMPV) infection in 1,505 children and their households, and compared it with infections due to respiratory syncytial virus (RSV) and influenza viruses. Nasopharyngeal swabs were used at enrollment to collect specimens for the detection of hMPV, RSV, and influenza virus RNA by reverse-transcriptase polymerase chain reaction (RT-PCR). hMPV was detected in 42 children (2.8%), RSV in 143 (9.5%; P < 0.0001 vs. hMPV), and influenza viruses in 230 (15.3%; P < 0.0001 vs. hMPV). Of the 42 hMPV-positive samples, one was also positive for RSV and six for influenza viruses, for a co-infection rate of 16.7%. Clinically, hMPV was identified only in patients with acute respiratory infection, whereas RSV and influenza viruses were also detected in patients with different clinical manifestations. Symptoms with statistically significant different proportions at presentation were fever (more frequent in the hMPV- and influenza-positive children) and wheezing with bronchiolitis or asthma exacerbation (more frequent among hMPV- and RSV-positive cases). The households of the hMPV- and the influenza-positive children had significantly more illnesses, needed significantly more medical visits, received more antipyretics, and missed significantly more work or school days than those of the RSV-positive children. Results show that hMPV is an emerging cause of acute respiratory infection in childhood, and may have a significant clinical and socioeconomic impact on children and their families.

In order to evaluate the use of an algorithm based on a procalcitonin (PCT) cut-off value as a means of guiding antibiotic therapy, 319 hospitalised children with uncomplicated community-acquired pneumonia (CAP) were randomised 1:1 to be treated on the basis of the algorithm or in accordance with standard guidelines. The children in the PCT group did not receive antibiotics if their PCT level upon admission was <0.25 ng/mL, and those receiving antibiotics from the time of admission were treated until their PCT level was ≥ 0.25 ng/mL. The final analysis was based on 155 patients in the PCT group and 155 in the control group. In comparison with the controls, the PCT group received significantly fewer antibiotic prescriptions (85.8% vs 100%; p < 0.05), were exposed to antibiotics for a shorter time (5.37 vs 10.96 days; p < 0.05), and experienced fewer antibiotic-related adverse events (3.9% vs 25.2%; p < 0.05), regardless of CAP severity. There was no significant between-group difference in recurrence of respiratory symptoms and new antibiotic prescription in the month following enrollment. The results of this first prospective study using a PCT cut-off value to guide antibiotic therapy for pediatric CAP showed that this approach can significantly reduce antibiotic use and antibiotic-related adverse events in children with uncomplicated disease. However, because the study included mainly children with mild to moderate CAP and the risk of the use of the algorithm-based approach was not validated in a relevant number of severe cases, further studies are needed before it can be used in routine clinical practice.

This prospective clinical and virological study of 2,060 otherwise healthy children aged <15 years of age (1,112 males; mean age +/- SD, 3.46 +/- 3.30 years) who attended the Emergency Department of Milan University's Institute of Pediatrics because of an acute disease excluding trauma during the winter season 2003-2004 was designed to compare the prevalence and clinical importance of human coronaviruses (HCoVs) in children. Real-time polymerase chain reaction (PCR) in nasopharyngeal aspirates revealed HCoV infection in 79 cases (3.8%): 33 HCoV-229E (1.6%), 13 HCoV-NL63 (0.6%), 11 HCoV-OC43 (0.5%), none HCoV-HKU1 genotype A, and 22 (1.1%) co-detections of a HCoV and another respiratory virus. The HCoVs were identified mainly in children with upper respiratory tract infection; there was no significant difference in clinical presentation between single HCoV infections and HCoV co-infections. Diagnostic methods were used in a limited number of patients, and the therapy prescribed and clinical outcomes were similar regardless of the viral strain. There were a few cases of other members of the households of HCoV-positive children falling ill during the 5-7 days following enrollment. These findings suggest that HCoV-229E and HCoV-OC43 have a limited clinical and socioeconomic impact on otherwise healthy children and their household contacts, and the HCoV-NL63 identified recently does not seem to be any different. The quantitative and qualitative role of HCoV-HKU1 genotype A is apparently very marginal.