Viral Infections in Children in the 2014/2015 Epidemic Season in Poland

In every epidemic season, viral infections affect the general population, including children, which is an underestimated issue. The present study demonstrates the results of examination of 802 clinical samples obtained from pediatric patients aged 0-14 years during the 2014/2015 epidemic season in Poland. The study was part of the virological surveillance systems - SENTINEL and NON-SENTINEL. A positive result for virological infection was obtained in 50.9 % of samples tested. The distribution of positive results by the age-groups was as follows: 38.2 % in 0-4 years old, 8.5 % in 5-9 years old, and 4.2 % in 10-14 years old children. Influenza viruses accounted for 48.0 % and influenza-like viruses for 52.0 % of all positive samples. Concerning the influenza virus, molecular biology-based techniques confirmed the infection caused by influenza type A in 63.3 % of samples, consisting of unsubtyped A virus detected in 65.3 % of cases of this sample group, subtype A/H1N1/pdm09 in 28.2 %, and subtype A/H3N2/ in 6.5 %. Genetic material of influenza B was detected in 36.7 % of samples. In a group of influenza-like viruses, the predominant virus was respiratory syncytial virus (RSV) in as many as 96.2 % of samples, followed by parainfluenza viruses: PIV3 - 1.4 % and PIV1 - 1.0 %. Attention should be paid to the coinfection of respiratory viruses. There were six possible coinfection combinations reported in Poland, with four of them related to children up to 14 years old.