Etiological detection and epidemiological analysis of children with influenza-like illness / 中华检验医学杂志

ABSTRACT

Objective:To analyze the status and epidemiological characteristics of respiratory virus infection in children with influenza-like illness in outpatient department, and to provide evidence for the prevention and treatment of children in this area.Methods:Nasopharyngeal swab samples were collected from children who attended the fever clinic of The Children′s Hospital, Zhejiang University School of Medicine due to influenza-like illness from July 2021 to March 2022, and six common respiratory virus nucleic acids were detected by reverse transcription-polymerase chain reaction (RT-PCR). The general information of the children was collected and grouped by gender and age (0-<6 months, 6-<12 months, 1-3< year-old, 3-<6 year-old , and ≥6 year-old), and the chi-square test was used for statistical analysis between the groups to explore the epidemic pattern of respiratory viruses.Results:A total of 739 cases (45.9%, 739/1 609) of respiratory viruses were detected from children with influenza-like illness, including 651 cases (40.5%, 651/1 609) of simple infection and 88 cases (5.5%, 88/1 609) of multiple infections. Respiratory syncytial virus (RSV) was detected in 18.6% (300/1 609), followed by influenza B virus (FluB) in 11.9% (192/1 609), adenovirus (ADV) in 8.3% (134/1 609), parainfluenza virus type 3 (PIV-3) in 7.6% (123/1 609), parainfluenza virus type 1 (PIV-1) in 4.9% (79/1 609), and influenza A virus (FluA) in 0.4% (6/1 609). Multiple infections including double or triple infections, with 81(92.0%, 81/88) cases of double infection and the most common being ADV+RSV (22.7%, 20/88) and 7 (8.0%, 7/88) cases of triple infection. There was a significant difference in the virus detection rate between the age groups (χ2=17.078, P=0.002), with the highest virus detection rate in the 3-<6 years of age group (49.7%, 286/575). Among the detection of simple infection, FluB had the highest detection rate in the ≥ 6 years of age group (26.6%, 98/369), and RSV and PIV-1 had the highest detection rate in the 3-<6 years of age group (20.0%, 115/575 and 5.9%, 34/575). The total monthly virus detection rate increased from 26.8% (37/138) in July to 63.0% (58/92) in January, and decreased to 46.1% (106/230) and 26.8% (37/138) in February and March. The detection rate of RSV was the highest from August to November, the detection rate of FluB was the highest from December to March, the detection rate of ADV increased in December and January, and the detection rate of PIV-3 increased from October to December; the detection rate of PIV-1 did not fluctuate significantly, and FluA was sporadically detected. Conclusions:RSV is the main respiratory virus in children with influenza-like illness. Most respiratory viruses are present as single infections. Multiple infections are more common in double infections. FluB, RSV and PIV-1 infections showed certain age distribution characteristics, especially in children over 3 years of age. The epidemic characteristics of respiratory virus infection show that the epidemic gradually peaks from summer to autumn and winter, and turns into an epidemic decline in spring. RSV was relatively prevalent in autumn, FluB was prevalent in winter and spring, ADV and PIV-3 were prevalent to varying degrees in winter, PIV-1 continued to circulate at a low level, and FluA did not present epidemic characteristics.