Objective:To explore the epidemiological characteristics of human metapneumovirus (hMPV) in children hospitalized for acute respiratory tract infections in Hebei, and provide a theoretical basis for the clinical diagnosis and treatment of acute respiratory tract infections in children in Hebei.Methods:Retrospectively, 41 499 children hospitalized in Hebei Children′s Hospital for acute respiratory tract infections from January 2017 to December 2021 were included to analyze the morbidity of children of different genders and ages, and in different seasons, and to statistically analyze the epidemiological data such as the positive detection rate of hMPV, the detection rates of mixed infections with other pathogens, and the clinical diagnosis.Results:The overall positive detection rate of hMPV in hospitalized children with acute respiratory infections from 2017 to 2021 was 5.94%(2 464/41 499), with the highest positive detection rate of hMPV in the age group of 3 to 4 years (7.66%, 520/6 789) and the lowest in the age group of ≥5 years (2.89%, 180/6 225), with a statistically significant difference ( P<0.001); the positive detection rates in male and female children were respectively 5.97%(1 496/25 056) and 5.94%(968/16 443), and the difference was not statistically significant ( P>0.05). The positive detection rates of hMPV from 2017 to 2021 were 5.10%(408/7 998), 9.64%(915/9 491), 4.27%(426/9 969), 5.91%(368/6 226), and 4.44%(347/7 815), respectively, and the positive detection rate of hMPV in 2018 was significantly higher than that in the other years ( P<0.001). hMPV circulated throughout the year, with obvious seasonality, with the highest positive detection rate in spring and winter.The mixed detection rate of hMPV with other respiratory pathogens was 42.74% (1 053/2 464), of which mixed detection with rhinovirus was the most common, with a mixed detection rate of 48.24%(508/1 053).Clinical diagnosis of hPMV-positive children was mostly bronchopneumonia. Conclusions:hMPV is one of the important pathogens in hospitalized children with acute respiratory infections in Hebei, which is common in children under 5 years of age and can occur throughout the year, with peak epidemics in winter and spring. Mixed infections of hMPV with other respiratory pathogens are common and can increase the risk of worsening clinical symptoms in children.

Objective:To explore the epidemiological characteristics of human metapneumovirus (hMPV) in children hospitalized for acute respiratory tract infections in Hebei, and provide a theoretical basis for the clinical diagnosis and treatment of acute respiratory tract infections in children in Hebei.Methods:Retrospectively, 41 499 children hospitalized in Hebei Children′s Hospital for acute respiratory tract infections from January 2017 to December 2021 were included to analyze the morbidity of children of different genders and ages, and in different seasons, and to statistically analyze the epidemiological data such as the positive detection rate of hMPV, the detection rates of mixed infections with other pathogens, and the clinical diagnosis.Results:The overall positive detection rate of hMPV in hospitalized children with acute respiratory infections from 2017 to 2021 was 5.94%(2 464/41 499), with the highest positive detection rate of hMPV in the age group of 3 to 4 years (7.66%, 520/6 789) and the lowest in the age group of ≥5 years (2.89%, 180/6 225), with a statistically significant difference ( P<0.001); the positive detection rates in male and female children were respectively 5.97%(1 496/25 056) and 5.94%(968/16 443), and the difference was not statistically significant ( P>0.05). The positive detection rates of hMPV from 2017 to 2021 were 5.10%(408/7 998), 9.64%(915/9 491), 4.27%(426/9 969), 5.91%(368/6 226), and 4.44%(347/7 815), respectively, and the positive detection rate of hMPV in 2018 was significantly higher than that in the other years ( P<0.001). hMPV circulated throughout the year, with obvious seasonality, with the highest positive detection rate in spring and winter.The mixed detection rate of hMPV with other respiratory pathogens was 42.74% (1 053/2 464), of which mixed detection with rhinovirus was the most common, with a mixed detection rate of 48.24%(508/1 053).Clinical diagnosis of hPMV-positive children was mostly bronchopneumonia. Conclusions:hMPV is one of the important pathogens in hospitalized children with acute respiratory infections in Hebei, which is common in children under 5 years of age and can occur throughout the year, with peak epidemics in winter and spring. Mixed infections of hMPV with other respiratory pathogens are common and can increase the risk of worsening clinical symptoms in children.

Objective:To investigate the epidemiological characteristics of human parainfluenza virus (HPIV) in hospitalized children with acute respiratory tract infection in Hebei region, providing reference for the diagnosis and prevention of children with respiratory tract infection.Methods:A retrospective analysis was performed on 20 577 children hospitalized with acute respiratory tract infection in Hebei Children′s Hospital from January 2022 to September 2023. Multiple PCR and capillary electrophoresis were used to detect HPIV and 12 other common respiratory viruses and atypical pathogens. The data from January to September 2022 were taken as the normalized epidemic prevention and control period, and the data from January to September 2023 were taken as the normalized epidemic control period. The epidemiological characteristics of HPIV were analyzed.Results:The overall HPIV-positive rate was 13.65% (2 808/20 577). There was no statistical difference in the total detection rate of HPIV [14.24%(1 236/8 679) and 14.35%(1 447/10 087)] at the same time before and after the novel coronavirus normalization prevention and control was lifted(χ 2= 0.041, P=0.839), while the detection rate of single infection [8.96%(778/8 679) and 7.58%(765/10 087)] decreased, while mixed infection [5.28%(458/8 679) and 6.76%(682/10 087)] increased, with statistically significant differences(χ 2= 11.776 and 18.008, P<0.01). The HPIV positive rate in the <1 year [18.53%(378/2 040) and 17.08%(369/2 161)] decreased after the release of normalized prevention and control, and the difference was statistically significant(χ 2= 5.932, P<0.05). The HPIV positive rate [13.03%(382/2 932) and 14.82%(529/3 570)] in the 3-5 years increased after the normalized prevention and control was lifted, and the difference was statistically significant(χ 2= 7.177, P<0.05). The rate of mixed infection of HPIV with other respiratory pathogens was 43.13% (1 211/2 808), among which double infection was 34.40% (966/2 808), triple infection was 7.55% (212/2 808), and quadruple infection was 1.18% (33/2 808). Mixed detection of HPIV and HRV (38.65%, 468/1 211) was the most common. Conclusions:HPIV is one of the respiratory pathogens in children in Hebei region and more prevalent in spring and summer. The susceptible population of HPIV is mainly children under the age of 3 years old. After the normal prevention and control of novel coronavirus was lifted, the detection rate of HPIV combined with other pathogens increased.

Objective:To investigate the epidemiological characteristics of human parainfluenza virus (HPIV) in hospitalized children with acute respiratory tract infection in Hebei region, providing reference for the diagnosis and prevention of children with respiratory tract infection.Methods:A retrospective analysis was performed on 20 577 children hospitalized with acute respiratory tract infection in Hebei Children′s Hospital from January 2022 to September 2023. Multiple PCR and capillary electrophoresis were used to detect HPIV and 12 other common respiratory viruses and atypical pathogens. The data from January to September 2022 were taken as the normalized epidemic prevention and control period, and the data from January to September 2023 were taken as the normalized epidemic control period. The epidemiological characteristics of HPIV were analyzed.Results:The overall HPIV-positive rate was 13.65% (2 808/20 577). There was no statistical difference in the total detection rate of HPIV [14.24%(1 236/8 679) and 14.35%(1 447/10 087)] at the same time before and after the novel coronavirus normalization prevention and control was lifted(χ 2= 0.041, P=0.839), while the detection rate of single infection [8.96%(778/8 679) and 7.58%(765/10 087)] decreased, while mixed infection [5.28%(458/8 679) and 6.76%(682/10 087)] increased, with statistically significant differences(χ 2= 11.776 and 18.008, P<0.01). The HPIV positive rate in the <1 year [18.53%(378/2 040) and 17.08%(369/2 161)] decreased after the release of normalized prevention and control, and the difference was statistically significant(χ 2= 5.932, P<0.05). The HPIV positive rate [13.03%(382/2 932) and 14.82%(529/3 570)] in the 3-5 years increased after the normalized prevention and control was lifted, and the difference was statistically significant(χ 2= 7.177, P<0.05). The rate of mixed infection of HPIV with other respiratory pathogens was 43.13% (1 211/2 808), among which double infection was 34.40% (966/2 808), triple infection was 7.55% (212/2 808), and quadruple infection was 1.18% (33/2 808). Mixed detection of HPIV and HRV (38.65%, 468/1 211) was the most common. Conclusions:HPIV is one of the respiratory pathogens in children in Hebei region and more prevalent in spring and summer. The susceptible population of HPIV is mainly children under the age of 3 years old. After the normal prevention and control of novel coronavirus was lifted, the detection rate of HPIV combined with other pathogens increased.

Objective:To analyze the clinical characteristics of pertussis cases diagnosed by two pathological detection methods: bacterial culture and real-time polymerase chain reaction (RT-PCR), and to explore the applicable value of two pathological detection methods in the diagnosis of pertussis.Methods:Bilateral nasopharyngeal swabs and clinical information of 165 children suspected of pertussis were collected by Hebei Children′s Hospital from April 2019 to January 2020. The bacterial culture and RT-PCR for nasopharyngeal swab specimens were performed in all cases. Chi-square test was used to analyze the cases of pertussis diagnosed by the above two methods.Results:Based on clinical diagnosis, the sensitivity of bacterial culture and RT-PCR for the diagnosis of pertussis was 61.70% (58/94) and 86.17% (81/94), and the specificity was 92.96% (66/71) and 71.83% (51/71), respectively. The positive rate of RT-PCR in children of all ages, seasons and cough courses is higher than that of bacterial culture. Children with pertussis diagnosed by bacterial culture and RT-PCR were basically similar in age, season, and cough course distribution, with the most common cases ≤3 months old, a high incidence trend in summer and autumn, and the course of coughing in children was mostly within 15-21days. The positive rate of bacterial culture in the diagnosis of pertussis in children is affected by the age of the children, and there are statistical differences between children in different age groups (χ2= 11.929, P=0.036). The positive rate of bacterial culture was the highest in children with >3 years old (51.85% [14/27]), followed by children with ≤3 months old (48.72% [19/39]), and the lowest in children with >6-12 months old (15.00% [3/20]). Moreover, the positive rate of bacterial culture in the diagnosis of pertussis in children is also affected by the cough course of the children, and there are statistical differences between children in different cough course groups (χ2=9.841, P=0.020). The positive rate of bacterial culture was the highest in children with cough course 15-21 days (49.23% [32/65]), followed by 43.59% (17/39) in children with cough course 8-14 days, and the lowest in children with cough course of less than 7 days (22.86% [8/35]). Conclusions:Compared with RT-PCR, bacterial culture has lower sensitivity and higher specificity in the detection of pertussis. These two detection methods have their own advantages and limitations. Medical institutions at all levels should comprehensively analyze different laboratory detection methods. Only by combining the two methods can the diagnostic value and level be effectively improved.

Objective:To analyze the changes in T lymphocyte subsets, B lymphocytes and NK cells in children with active tuberculosis (TB) and their clinical significance.Methods:T lymphocyte subsets, B lymphocytes and NK cells in peripheral blood samples of 106 patients with acute TB (TB group) and 106 healthy children (healthy control group) were detected by flow cytometry and compared between different groups.Results:The percentages of CD3 + T, CD4 + T and NK cells as well as the CD4 +/CD8 + T cell ratio were significantly lower in the TB group than in the healthy control group ( Z=-3.783, P=0.000; Z=-5.401, P=0.000; Z=-3.434, P=0.001; Z=-2.014, P=0.044). The percentages of double negative T (DNT) and B cells in the TB group were significantly higher than those in the healthy control group ( Z=2.765, P=0.006; Z=6.880, P=0.000). No significant difference in the percentage of CD8 + T or double positive T (DPT) cells was observed between the two groups ( P>0.05). The expression of peripheral lymphocyte subsets varied in TB children of different age groups (0-<3, 3-<6, 6-<10 and 10-<16 years old). There were significant differences in CD3 + T, DNT and B cells among the four age groups ( H=10.081, P=0.018; H=14.583, P=0.002; H=8.498, P=0.037). The percentage of CD4 + T cells was significantly lower in children with extrapulmonary TB than in those with pulmonary TB ( Z=-3.068, P=0.002). No statistically significant difference in other lymphocyte subsets was found between children with extrapulmonary and pulmonary TB ( P>0.05). Conclusions:Tuberculosis could lead to immune dysfunction in children. Dynamic monitoring of the changes in peripheral lymphocyte subsets in children with TB could be conducive to better assessment of immune status and providing personalized treatment.

Objective:To investigate the epidemiological characteristics of human coronavirus (HCoV) in hospitalized children with respiratory tract infection in Hebei region, providing evidence for the diagnosis and prevention of children with respiratory tract infection.Methods:A retrospective study was conducted on 1 062 HCoV positive children hospitalized for respiratory tract infection in Children′s Hospital of Hebei Province from January 2015 to December 2020, aged from 33 days to 14 years, with a median age of 2 years. 27 932 (60.9%) were males and 17 944(39.1%) were females. And the gender, ages, seasonal distribution, HCoV-positive rates, co-detection distribution and clinical diagnosis of HCoV positive cases were analyzed by SPSS 25.0. Enumeration data were expressed by frequency and percentage; categorical variable were compared by the Pearson χ 2test. Results:The overall HCoV-positive rate was 2.31% (1 062/45 876), which was 2.37% (662/27 932) in male children and 2.23% (400/17 944) in female children. There was no statistically significant difference between genders (χ2=0.916, P=0.339). Children at age groups<1 years (2.44%) and 1-<3 years (2.63%) had higher HCoV-positive rates than those at age groups 3-<5 years (1.97%) and ≥5 years (1.38%) (χ2=27.332, P<0.01). The HCoV-positive rates from 2015 to 2018 were 2.13%, 2.45%, 2.28% and 2.23%. The HCoV-positive rate of 2019 (1.71%) was significantly lower than in 2016 (χ2=12.05, P<0.01), 2017 (χ2=7.34, P=0.01) and 2018 (χ2=6.78, P=0.01), but there was no significant difference compared with 2015 (χ2=2.84, P=0.09). The HCoV-positive rate of 2020 (3.37%) was significantly higher than in 2015 (χ2=13.636, P<0.01), 2016 (χ2=11.099, P<0.01), 2017 (χ2=15.482, P<0.01), 2018(χ2=18.601, P<0.01) and 2019(χ2=45.580, P<0.01). The positive rate was highest in spring (March to May) in 2015 and 2017 to 2018. February to April and July to September of 2016 were the peak periods of positive detection. No obvious seasonal change was observed in 2019 and the HCoV-positive rate of 2020 was extremely low from January to July, following significantly increased from August to December. 26.37% (280/1 062) of HCoV were co-detected with other respiratory pathogens and the most frequently identified mixed detection was RSV. Three or more pathogens were detected in 7.34% (78/1 062) of the HCoV-positive samples. Bronchopneumonia and bronchiolitis were more frequently observed in the single HCoV positive (61.89% and 16.75%) children compared to co-detected children(34.29% and 9.64%)(χ2=63.394 and 8.228, P<0.01). However, compared to those with HCoV mono-detection, co-detected children were more likely to have severe pneumonia (4.6% and 47.14%) (χ2=280.171, P<0.01). Conclusions:HCoV is one of the respiratory pathogens in children in Hebei region and more prevalent in spring. The susceptible population of HCoV is mainly children under the age of 3 years old. HCoV often co-detects with other respiratory pathogens, and the co-infection is one of the risk factors of severe pneumonia in children with respiratory infection.

Objective:To investigate the epidemiological characteristics of human coronavirus (HCoV) in hospitalized children with respiratory tract infection in Hebei region, providing evidence for the diagnosis and prevention of children with respiratory tract infection.Methods:A retrospective study was conducted on 1 062 HCoV positive children hospitalized for respiratory tract infection in Children′s Hospital of Hebei Province from January 2015 to December 2020, aged from 33 days to 14 years, with a median age of 2 years. 27 932 (60.9%) were males and 17 944(39.1%) were females. And the gender, ages, seasonal distribution, HCoV-positive rates, co-detection distribution and clinical diagnosis of HCoV positive cases were analyzed by SPSS 25.0. Enumeration data were expressed by frequency and percentage; categorical variable were compared by the Pearson χ 2test. Results:The overall HCoV-positive rate was 2.31% (1 062/45 876), which was 2.37% (662/27 932) in male children and 2.23% (400/17 944) in female children. There was no statistically significant difference between genders (χ2=0.916, P=0.339). Children at age groups<1 years (2.44%) and 1-<3 years (2.63%) had higher HCoV-positive rates than those at age groups 3-<5 years (1.97%) and ≥5 years (1.38%) (χ2=27.332, P<0.01). The HCoV-positive rates from 2015 to 2018 were 2.13%, 2.45%, 2.28% and 2.23%. The HCoV-positive rate of 2019 (1.71%) was significantly lower than in 2016 (χ2=12.05, P<0.01), 2017 (χ2=7.34, P=0.01) and 2018 (χ2=6.78, P=0.01), but there was no significant difference compared with 2015 (χ2=2.84, P=0.09). The HCoV-positive rate of 2020 (3.37%) was significantly higher than in 2015 (χ2=13.636, P<0.01), 2016 (χ2=11.099, P<0.01), 2017 (χ2=15.482, P<0.01), 2018(χ2=18.601, P<0.01) and 2019(χ2=45.580, P<0.01). The positive rate was highest in spring (March to May) in 2015 and 2017 to 2018. February to April and July to September of 2016 were the peak periods of positive detection. No obvious seasonal change was observed in 2019 and the HCoV-positive rate of 2020 was extremely low from January to July, following significantly increased from August to December. 26.37% (280/1 062) of HCoV were co-detected with other respiratory pathogens and the most frequently identified mixed detection was RSV. Three or more pathogens were detected in 7.34% (78/1 062) of the HCoV-positive samples. Bronchopneumonia and bronchiolitis were more frequently observed in the single HCoV positive (61.89% and 16.75%) children compared to co-detected children(34.29% and 9.64%)(χ2=63.394 and 8.228, P<0.01). However, compared to those with HCoV mono-detection, co-detected children were more likely to have severe pneumonia (4.6% and 47.14%) (χ2=280.171, P<0.01). Conclusions:HCoV is one of the respiratory pathogens in children in Hebei region and more prevalent in spring. The susceptible population of HCoV is mainly children under the age of 3 years old. HCoV often co-detects with other respiratory pathogens, and the co-infection is one of the risk factors of severe pneumonia in children with respiratory infection.

Objective To analyze the molecular epidemiology of adenovirus ( ADV) causing acute respiratory diseases and to investigate the mixed infection of ADV and other respiratory pathogens in Hebei Province. Methods Sputum samples were collected from inpatient children with acute respiratory diseases at Children′s Hospital of Hebei Province between June 2017 and May 2018. Multiplex reverse transcription PCR assay was used to detecte 13 kinds of respiratory pathogens. Nested PCR was performed to amplify ADV hexon gene and the amplified products were then sequenced. Results A total of 353 ADV-positive speci-mens were detected in 8839 specimens with a positive rate of 3. 99％. Significant difference in the positive rate of ADV was not observed between male and female patients (χ2=0. 0003, P=0. 99), but found among different age groups (χ2=115. 69, P<0. 001). All isolated ADV strains belonged to 11 serotypes, which were type 1 (16. 15％, 57/353), type 2 (35. 98％, 127/353), type 3 (21. 25％, 75/353), type 4 (1. 13％, 4/353), type 5 (11. 33％, 40/353), type 6 (3. 97％, 14/353), type 7 (8. 22％, 29/353), type 31 (0. 28％, 1/353), type 41 (0. 28％, 1/353), type 55 (0. 28％, 1/353) and type 57 (1. 13％, 4/353). Among the 353 ADV-positive specimens, 259 were mixed infections mainly caused by ADV and human rhinovirus (35. 52％). ADV and respiratory syncytial virus co-infections accounted for 12. 74％ and 33. 20％ of the mixed infections involved three or more pathogens. ADV could be detected throughout the year, especially in September and April to May. The predominant serotypes were types 1, 2 and 3. The av-erage ages of the two groups of ADV infection alone and ADV mixed infection were (27. 56±24. 67) months and (21. 33 ±20. 28) months, respectively, and the difference between them was statistically significant (P=0. 037). The incidence of ADV 2 infection alone was 25. 77％ (25/97), which was lower than that of ADV 2-involved mixed infection [39. 84％ (102/256),χ2=6. 05, P=0. 014]. However, the rate of ADV 7 infection alone was significantly higher than that of ADV 7-involved mixed infection [16. 49％ 16/97) vs 5. 08％ (13/256),χ2=6. 05, P<0. 001]. Conclusion ADV 1, ADV 2 and ADV 3 were the predominant serotypes circulating in Hebei Province from June 2017 to May 2018, especially in September and April to May. The younger the patients were, the higher the incidence would be. ADV 2 was prone to cause mixed infections with other respiratory pathogens, while ADV 7 was less common in mixed infections. Younger pa-tients were more susceptible to mixed infections. The most common co-infection was caused by ADV and hu-man rhinovirus.

Objective To develop a tetra-primer amplification refractory mutation system PCR(T-ARMS-PCR)assay for detecting four single nucleotide polymorphisms(SNPs): rs1801133,rs1801131, rs1805087 and rs1801394 associated with folate metabolism in a single reaction tube.Methods Methodology was developed.Then, it applied the established method to analyze 150 physical examination children′s anticoagulant blood samples admitted to the Department of Clinical Laboratory, Children′s Hospital of Hebei Province from January 2017 to April 2017.Four sets of chimeric primers consisting of a universal Tag sequence and targeting rs 1801133,rs1801131,rs1805087 and rs1801394 fused to the specific sequence were designed according to the T-ARMS-PCR principle and the multiplex chimeric primers strategy.A single tube PCR was then conducted after optimizing the primer concentrations and the reaction conditions.The amplified products were analyzed by QIAxcel capillary electrophoresis, and the corresponding SNP genotypes of 150 samples were identified.Furthermore,all samples were verified by direct sequencing.And the Hardy-Weinberg Equilibrium(HWE)testing of four SNPs from 150 samples were conducted by SPSS17.0 Chi-square test.Results The improved T-ARMS-PCR combined with capillary electrophoresis can accurately verify eight different alleles of the four SNPs associated with folate metabolism at one time in 3 hours.Four SNPs of 150 whole blood samples were accurately classified and the results were completely consistent with direct sequencing.All the genotype frequencies of these four SNPs were in HWE (χ2rs1801133=0.69, Prs1801133=0.40; χ2rs1801131=0.21, Prs1801131=0.64; χ2rs1805087=3.32, Prs1805087=0.07;χ2rs1801394=1.91, Prs1801394=0.17).Conclusions The proposed improved T-ARMS-PCR combined with capillary electrophoresis in this study can accurately verify four SNPs associated with folate metabolism in a single reaction tube.This method might be a valuable tool to specifically guide the folate supplement in general population.