Epidemiological characteristics of adenovirus infection in hospitalized children with acute respiratory tract infection in Kunming during 2019

Abstract

Objective: To investigate the epidemiology and clinical characteristics of adenovirus (ADV)-caused acute respiratory tract infection among hospitalized children in Kunming, China. Methods: Clinical and laboratory data were collected from 467 children with adenovirus infection who were hospitalized from January 1, 2019 to December 31, 2019 in 6 grade A class Ⅲ hospitals in Kunming area. The basic characteristics, epidemiology, mixed infection and adenovirus genotypes of the patients were retrospectively analyzed. The patients diagnosed with adenovirus pneumonia (AP) were divided into two groups, severe AP (SAP) group and general AP(GAP) group according to the severity of illness. Mann-Whitney U test or χ2 test was used for comparison between groups, while multivariate regression was applied to analyze the risk factors of SAP. Results: Among 15 635 hospitalized children with respiratory tract infection, 467 cases were adenovirus positive, with a detection rate of 2.99%. Of the 467 patients with adenovirus infection, 284 were male and 183 female, the age was 2.4 (1.1,3.9) years, including 44 cases (9.4%) < 0.5 years, 59 cases (12.6%) of 0.5 to<1.0 years, 176 cases (37.7%) of 1.0 to <3.0 years, 150 cases (32.1%) of 3.0 to <7.0 years, and 38 cases (8.1%) of 7.0 to 14.0 years. Adenovirus infection was common in autumn and winter, and the high incidence months were October to December, which accounted for 51.6% (241/467) of the whole year cases. Co-infection was detected in 226 cases (48.4%) out of 467 patients, in which one pathogen co-infection was the most frequent form (172 cases, 76.1%). Of the 262 pathogen detected 108 (41.2%) were Mycoplasma pneumoniae. In 144 of ADV-positve cases (30.8%) were taken geno-typing was done by PCR amplification, the results showed that 74 cases (51.4%) were ADV 3, 7 subtypes and 65 cases (45.1%) of ADV 1, 2,6 subtypes. Of the 467 cases of ADV infection, 320 (68.5%) were diagnosed with pneumonia, 82 (17.6%) with upper respiratory tract infection and pharyngeal tonsillitis, and 65 (13.9%) with bronchitis, laryngeal bronchitis, and asthmatic bronchitis. Among the 320 patients with AP, 56 cases were severe and 264 cases were general. Two cases (3.6%) in severe group died. Compared with the GAP group, the age was young [17 (11,42) months vs. 24 (14,44) months, Z=2.222, P=0.026], the fever duration was long [8 (5,14) days vs. 6 (3,9) days, Z=3.380, P<0.01], and the proportions of preterm birth and having underlying diseases were high [respectively 19.6% (11/56) vs. 6.1% (16/264), 26.8% (15/56) vs. 10.2% (27/264), χ2=8.965,11.109, P<0.05] in SAP group. Referring to laboratory markers, white blood cell count, C-reactive protein, creatine kinase-MB and lactate dehydrogenase were significantly increased in SAP group as compared to GAP group(all P<0.05). Multivariate Logistic regression analysis showed that preterm birth (OR=3.284, 95%CI 1.079-9.993, P=0.036), underlying disease (OR=3.284, 95%CI 1.079-9.993, P=0.036), fever duration ≥10 d (OR=2.523,95%CI 1.195-5.328, P=0.015) and C-reactive protein ≥50 mg/L (OR=3.156, 95%CI 1.324-7.524, P=0.010) were positively correlated with the risk of SAP. Conclusions: The incidence of adenovirus infection among hospitalized children in Kunming was lower than the national level, and no outbreak occurred in 2019. Subtype 3 and 7 of ADV are the predominant strains for infection, which usually occurs in autumn and winter and mainly causes pneumonia. Premature birth, underlining diseases, long fever duration and markedly increased C-reactive protein are the risk factors for developing into severe pneumonia. This paper presents the prevalence and clinical characteristics of adenovirus infection in children at high altitude area.