Objective:To analyze the epidemiological distribution characteristics, influencing factors, and infection rates of pertussis in the population of Henan Province.Methods:From 2022 to 2023, a cross-sectional survey was conducted to investigate the permanent population in Henan Province. Enzyme-linked immunosorbent assay (ELISA) was used to detect anti-pertussis toxin IgG (PT-IgG), analyze the antibody positivity rate (≥20 IU/ml) and median concentration (MC), and estimate the pertussis infection rate based on PT IgG ≥40 IU/ml. The rank sum test was used to compare antibody levels among groups, and the χ2 test was used to compare antibody positive rates and infection rates among groups. Results:A total of 4 810 research subjects were included in this study. The overall positive rate of PT-IgG was 12.10% and MC was 3.04 (0.35, 10.36) IU/ml. There were significant differences both in positive rates and antibody levels of PT-IgG among different regions or age groups (region positive rate: χ2=134.06, P<0.001, MC: H=337.74, P<0.001; age group positive rate: χ2=45.27, P<0.001, MC: H=134.49, P<0.001). Both the positive rate of PT-IgG (25.26%) and MC (8.01 IU/ml) were the highest within one year after completing a full course of vaccination. There were significant differences in positive rates and antibody levels among people receiving different types of pertussis vaccines (positive rate: χ2=12.38, P=0.006, MC: H=17.93, P<0.001). The antibody positivity rate (35.71%) and MC (8.88 IU/ml) of the people who received cell-free pertussis inactivated poliomyelitis influenza type b (combined) vaccine throughout the course were higher than those who received other types of vaccines. The natural infection rate of pertussis was evaluated for individuals aged≥3 years who had no history of pertussis vaccine immunization within the year prior to sampling. With a high vaccination rate, the estimated infection rate of pertussis in the population was 5 757.22/100 000. The infection rates in the 3-year-old (1 940.16/100 000) and 4-year-old (1 765.68/100 000) populations were at a low level among the entire population, reaching their peak at the age of 6 (12 656.71/100 000). Subsequently, although the infection rate continued to decline, it remained at a high level and peaked again at the age of 40-49 years (8 740.39/100 000). There was a statistically significant difference in the estimated infection rate of pertussis among different age groups ( χ2=53.21, P<0.001). Conclusion:The PT-IgG level of pertussis in the population of Henan Province is generally at a low level. The estimated infection rate of pertussis is much higher than the reported incidence rate. A booster dose of pertussis vaccine is recommended at 6 years old.

Objective:To analyze the epidemiological distribution characteristics, influencing factors, and infection rates of pertussis in the population of Henan Province.Methods:From 2022 to 2023, a cross-sectional survey was conducted to investigate the permanent population in Henan Province. Enzyme-linked immunosorbent assay (ELISA) was used to detect anti-pertussis toxin IgG (PT-IgG), analyze the antibody positivity rate (≥20 IU/ml) and median concentration (MC), and estimate the pertussis infection rate based on PT IgG ≥40 IU/ml. The rank sum test was used to compare antibody levels among groups, and the χ2 test was used to compare antibody positive rates and infection rates among groups. Results:A total of 4 810 research subjects were included in this study. The overall positive rate of PT-IgG was 12.10% and MC was 3.04 (0.35, 10.36) IU/ml. There were significant differences both in positive rates and antibody levels of PT-IgG among different regions or age groups (region positive rate: χ2=134.06, P<0.001, MC: H=337.74, P<0.001; age group positive rate: χ2=45.27, P<0.001, MC: H=134.49, P<0.001). Both the positive rate of PT-IgG (25.26%) and MC (8.01 IU/ml) were the highest within one year after completing a full course of vaccination. There were significant differences in positive rates and antibody levels among people receiving different types of pertussis vaccines (positive rate: χ2=12.38, P=0.006, MC: H=17.93, P<0.001). The antibody positivity rate (35.71%) and MC (8.88 IU/ml) of the people who received cell-free pertussis inactivated poliomyelitis influenza type b (combined) vaccine throughout the course were higher than those who received other types of vaccines. The natural infection rate of pertussis was evaluated for individuals aged≥3 years who had no history of pertussis vaccine immunization within the year prior to sampling. With a high vaccination rate, the estimated infection rate of pertussis in the population was 5 757.22/100 000. The infection rates in the 3-year-old (1 940.16/100 000) and 4-year-old (1 765.68/100 000) populations were at a low level among the entire population, reaching their peak at the age of 6 (12 656.71/100 000). Subsequently, although the infection rate continued to decline, it remained at a high level and peaked again at the age of 40-49 years (8 740.39/100 000). There was a statistically significant difference in the estimated infection rate of pertussis among different age groups ( χ2=53.21, P<0.001). Conclusion:The PT-IgG level of pertussis in the population of Henan Province is generally at a low level. The estimated infection rate of pertussis is much higher than the reported incidence rate. A booster dose of pertussis vaccine is recommended at 6 years old.

Objective:To investigate the types and distribution of non-polio enterovirus (NPEV) in acute flaccid paralysis (AFP) cases in Henan Province in 2019.Methods:A total of 513 cases of AFP were reported in Henan Province in 2019. Two stool specimens were collected from each case for virus isolation. The VP1 gene of NPEV-positive strains was amplified and sequenced. Sequence alignment and construction of the phylogenetic tree were completed by MEGA5.1 software. The epidemiological data of NPEV-positive strains were statistically analyzed by Excel 2016 and SPSS19 software.Results:A total of 39 NPEV strains were isolated from 513 AFP cases, with an isolation rate of 7.60% (39/513). Among them, 18 strains were group A viruses and 21 strains were group B viruses. Both group A and group B viruses contained seven serotypes. No viruses of group C and group D was isolated. Coxsackievirus A type 4 (CVA4) and CVA16 were the predominant types in group A, and echovirus type 11 (Echo11) was the predominant type in group B. The nucleotide identity between the NPEV-positive strains was 67.4%-100.0%, and their nucleotide identity with the prototype strain was 71.4%-85.6%. NPEV was mainly detected in scattered children under 7 years old with an isolation rate of 84.62% (33/39), and the ratio of male to female was 2.07∶1. No statistically significant difference in the isolation rate was found between different age groups or between different sexes ( P>0.05). Among the group A viruses, CVA2, CVA4 and CVA16 were widely distributed. Echo3, Echo11 and Echo30 were the widely distributed group B viruses. NPEV could be isolated throughout the year except for January. Group A virus infections mainly occurred from April to July, accounting for 66.67% (12/18) of the whole year. Group B virus infections mainly occurred in September, accounting for 28.57% (6/21) of the whole year. Conclusions:The main serotype of NPEV isolated in Henan Province in 2019 was Echo11. The pathogen spectrum and regional distribution of NPEV as well as the isolation rate in different age groups changed significantly compared with those in 2018. Therefore, it was necessary to strengthen monitoring and conduct targeted prevention and control to effectively reduce the occurrence of AFP.

Objective:To investigate the serotypes and epidemic characteristics of non-polio enteroviruses (NPEV) in acute flaccid paralysis (AFP) cases in Henan Province in 2021.Methods:Fecal specimens of 529 AFP cases reported in Henan Province in 2021 were collected for virus isolation. The VP1 regions of NPEV were sequenced. MEGA5.1 software was used for sequence alignment and a phylogenetic tree was constructed as well. The epidemiological data were organized and statistically analyzed using Excel2016 and SPSS26 software.Results:A total of 30 strains of NPEV were isolated from the fecal specimens of 529 AFP cases, with an isolation rate of 5.67% (30/529). They were belonged to group A and group B with 15 strains in each group, and no group C or group D viruses were isolated. Group A contained six serotypes and was dominated by coxsackievirus A2 (CVA2) and CVA6. Group B contained tree serotypes and was dominated by CVB3. In the population distribution, the separation rate of NPEV was the highest among children under 5 years old, which was 76.67% (23/30), and the ratio of male to female was 1.51∶1. In the regional distribution, group A viruses were mainly distributed in the central, southern and southwestern parts of Henan Province with CVA2 and CVA4 being the most widely distributed, while group B viruses were relatively concentrated, mainly distributed in the central, northern and southwestern parts of Henan Province with CVB3 being the predominant. In terms of time distribution, NPEV could be isolated throughout the year except from January to February, showing the epidemic characteristics of high incidence in spring and summer and low incidence in autumn and winter. The peak of group A virus infection was in May and the peak period of group B virus infection was from June to July.Conclusions:CVB3 was the main serotype of NPEV isolated in Henan Province in 2021. The pathogenic spectrum and regional distribution of NPEV had changed significantly compared with those in 2018-2019. In order to provide reference for the diagnosis and surveillance of AFP and maintain the polio-free status in Henan Province, much attention should be paid to the current epidemic trend of NPEV.

Objective:To analyze the seroepidemiological characteristics of hepatitis B virus (HBV) infection among adolescents aged 0-14 years in Henan Province and to evaluate the effectiveness of the childhood hepatitis B vaccine (HepB) immunization program.Methods:From September 2021 to March 2022, a total of 4 883 adolescents aged 0-14 years were selected from 25 villages or communities of 18 provincial-level cities in Henan Province by using the multi-stage random cluster sampling method. Demographic data were collected through questionnaires. The 3 ml of blood samples were collected from individuals aged 0-4 years and 5 ml of blood samples were collected from individuals aged 5-14 years to test HBsAg, HBcAb and HBsAb. Data on vaccination were collected through Henan Provincial Immunization Information System and hepatitis B cases in Henan Province were collected through China Infectious Disease Reporting System. The effectiveness of the childhood HepB immunization program was analyzed.Results:The average age of 4 883 subjects was (7.32±2.81) years old. The positive rates of HBsAg and HBcAb were 0.1% (7/4 883) and 1.0% (50/4 883), and the population standardized rates were 0.3% and 1.7%. In 2002, the positive rate of HBsAg among adolescents aged 0-14 years in Henan Province was 3.39%. Compared with that in 2002, the number of chronic HBV infections among adolescents in Henan Province in 2022 decreased by about 0.7 million. In 2002, the vaccination rate of newborns who completed all three doses of vaccine was 6.26%. In 2003, the vaccination rate of the hepatitis B vaccine rose rapidly, reaching 90% in 2013 for the first time. After 2014, the vaccination rate in Henan Province continued to remain above 95%. The proportion of cases among children aged 1-4 years in clinical reports decreased from 0.43% (1 108/256 566) in 2006 to 0.01% (78/80 655) in 2021. The proportion of cases among adolescents aged 5-19 years decreased from 18.21% (46 710/256 566) in 2006 to 1.1% (827/80 655) in 2021.Conclusions:From 2002 to 2022, the positive rate of HBsAg among adolescents aged 0-14 years has decreased significantly in Henan Province. The effectiveness of the HepB immunization program for children is good.

Objective:To analyze the seroepidemiological characteristics of hepatitis B virus (HBV) infection among adolescents aged 0-14 years in Henan Province and to evaluate the effectiveness of the childhood hepatitis B vaccine (HepB) immunization program.Methods:From September 2021 to March 2022, a total of 4 883 adolescents aged 0-14 years were selected from 25 villages or communities of 18 provincial-level cities in Henan Province by using the multi-stage random cluster sampling method. Demographic data were collected through questionnaires. The 3 ml of blood samples were collected from individuals aged 0-4 years and 5 ml of blood samples were collected from individuals aged 5-14 years to test HBsAg, HBcAb and HBsAb. Data on vaccination were collected through Henan Provincial Immunization Information System and hepatitis B cases in Henan Province were collected through China Infectious Disease Reporting System. The effectiveness of the childhood HepB immunization program was analyzed.Results:The average age of 4 883 subjects was (7.32±2.81) years old. The positive rates of HBsAg and HBcAb were 0.1% (7/4 883) and 1.0% (50/4 883), and the population standardized rates were 0.3% and 1.7%. In 2002, the positive rate of HBsAg among adolescents aged 0-14 years in Henan Province was 3.39%. Compared with that in 2002, the number of chronic HBV infections among adolescents in Henan Province in 2022 decreased by about 0.7 million. In 2002, the vaccination rate of newborns who completed all three doses of vaccine was 6.26%. In 2003, the vaccination rate of the hepatitis B vaccine rose rapidly, reaching 90% in 2013 for the first time. After 2014, the vaccination rate in Henan Province continued to remain above 95%. The proportion of cases among children aged 1-4 years in clinical reports decreased from 0.43% (1 108/256 566) in 2006 to 0.01% (78/80 655) in 2021. The proportion of cases among adolescents aged 5-19 years decreased from 18.21% (46 710/256 566) in 2006 to 1.1% (827/80 655) in 2021.Conclusions:From 2002 to 2022, the positive rate of HBsAg among adolescents aged 0-14 years has decreased significantly in Henan Province. The effectiveness of the HepB immunization program for children is good.