Objective:To investigate tetanus antibody levels and distribution characteristics in a healthy population of Henan Province.Methods:A cross-sectional survey was conducted in Henan Province from 2022 to 2023 to investigate the permanent population. Enzyme-linked immunosorbent assay (ELISA) was used to detect anti-tetanus toxoid IgG antibody (anti-TT), and the positive rate (≥0.01 IU/ml), protection rate (≥0.1 IU/ml) and concentration differences of tetanus antibodies in different populations were analyzed.Results:The age M ( Q1, Q3) of 5 494 participants was 14 (4, 40) years old, with a minimum age of 8 months and a maximum age of 81 years old. The male-to-female ratio was 1.00∶1.18. The total positive rate, protective rate and mean concentration (MC) [ M ( Q1, Q3)] of Anti-TT were 76.48%, 41.72% and 0.067 (0.010, 0.154) IU/ml, respectively. The positive rates of Anti-TT in individuals aged <3, 3-5, 6-9, and 10-14 were 95.32%, 96.05%, 97.81%, and 93.17%, respectively, but gradually decreased with age ( χ2trend=1 283.02, P<0.001). The antibody protection rate [82.13% (579/705)] and MC [ M ( Q1, Q3) of 0.160 (0.122, 0.259) IU/ml] in the population under 3 years old were relatively high, and both showed a decreasing trend with age (protection rate: χ2trend=1 889.49, P<0.001; MC: t=-54.22, P<0.001). There were significant differences in antibody levels among populations of different ages, regions, occupations, and immunization histories (all P<0.001). Within 13 years after the last dose of TTCV vaccination, the positive rate of Anti-TT was all greater than 90%, but the protection rate and MC continued to decrease with the prolongation of vaccination time (protection rate: χ2trend=160.58, P<0.001; MC: t=-14.93, P<0.001). After the last dose of vaccination, the protection rate and MC [ M ( Q1, Q3)] decreased to 30.43% and 0.055 (0.036, 0.115) IU/ml, respectively, for 10-13 years. The protection rates of Anti-TT for farmers, workers, people aged 60 and above, and women of childbearing age (20-45 years old) were 7.77%, 22.96%, 8.39%, and 12.72%, respectively. Conclusion:The level of tetanus antibodies in infants and young children in Henan Province is relatively high from 2022 to 2023, but it decreases with age and prolonged post-immunization time. There are significant differences in antibody levels among individuals of different ages, regions, occupations, and immunization histories. Occupational high-risk groups such as farmers and workers, elderly people, and women of childbearing age lack sufficient immunization protection.

Objective:To investigate tetanus antibody levels and distribution characteristics in a healthy population of Henan Province.Methods:A cross-sectional survey was conducted in Henan Province from 2022 to 2023 to investigate the permanent population. Enzyme-linked immunosorbent assay (ELISA) was used to detect anti-tetanus toxoid IgG antibody (anti-TT), and the positive rate (≥0.01 IU/ml), protection rate (≥0.1 IU/ml) and concentration differences of tetanus antibodies in different populations were analyzed.Results:The age M ( Q1, Q3) of 5 494 participants was 14 (4, 40) years old, with a minimum age of 8 months and a maximum age of 81 years old. The male-to-female ratio was 1.00∶1.18. The total positive rate, protective rate and mean concentration (MC) [ M ( Q1, Q3)] of Anti-TT were 76.48%, 41.72% and 0.067 (0.010, 0.154) IU/ml, respectively. The positive rates of Anti-TT in individuals aged <3, 3-5, 6-9, and 10-14 were 95.32%, 96.05%, 97.81%, and 93.17%, respectively, but gradually decreased with age ( χ2trend=1 283.02, P<0.001). The antibody protection rate [82.13% (579/705)] and MC [ M ( Q1, Q3) of 0.160 (0.122, 0.259) IU/ml] in the population under 3 years old were relatively high, and both showed a decreasing trend with age (protection rate: χ2trend=1 889.49, P<0.001; MC: t=-54.22, P<0.001). There were significant differences in antibody levels among populations of different ages, regions, occupations, and immunization histories (all P<0.001). Within 13 years after the last dose of TTCV vaccination, the positive rate of Anti-TT was all greater than 90%, but the protection rate and MC continued to decrease with the prolongation of vaccination time (protection rate: χ2trend=160.58, P<0.001; MC: t=-14.93, P<0.001). After the last dose of vaccination, the protection rate and MC [ M ( Q1, Q3)] decreased to 30.43% and 0.055 (0.036, 0.115) IU/ml, respectively, for 10-13 years. The protection rates of Anti-TT for farmers, workers, people aged 60 and above, and women of childbearing age (20-45 years old) were 7.77%, 22.96%, 8.39%, and 12.72%, respectively. Conclusion:The level of tetanus antibodies in infants and young children in Henan Province is relatively high from 2022 to 2023, but it decreases with age and prolonged post-immunization time. There are significant differences in antibody levels among individuals of different ages, regions, occupations, and immunization histories. Occupational high-risk groups such as farmers and workers, elderly people, and women of childbearing age lack sufficient immunization protection.

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.

Objective:To analyze the molecular characteristics of hemagglutinin-neuraminidase (HN) gene of human parainfluenza virus type 3 (HPIV3) among the cases with acute respiratory tract infection (ARI) in Henan Province.Methods:Nasal/throat swab samples collected from patients with severe acute respiratory tract infection (SARI) in Luohe and patients with influenza-like illness (ILI) in Zhengzhou were used in this study. HPIV nucleic acids in the samples were detected using real-time fluorescent PCR. HPIV3-positive samples were subjected to RT-PCR for the amplification of HN genes and the sequences were analyzed with Sanger method. CExpress and MEGA7.0 software were used for sequences editing, evolution tree construction and gene sequence analysis.Results:A total of 374 throat swab samples collected form ARI cases in Luohe and Zhengzhou were tested and 20 (5.3%) of them were positive for HPIV3. Eighteen HPIV3 HN gene sequences were successfully amplified and all belonged to C3 subgroups, including 16 sequences of C3f genotype and two sequences of C3a genotype. The 18 HN gene sequences shared the homology of 97.6%-100.0% in nucleotide and 99.3%-100.0% in amino acid, but the differences between them and the prototype strain Wash/47885/57 were significant. There were 12 amino acid mutations shared by them, including four function-related mutations (H295Y, I391V, D556N and I53T). There were no significant differences in the nucleotide or amino acid sequences as compared with the epidemic strain of China/BCH4210A/2014.Conclusions:The C3f and C3a branches of HPIV3 were the epidemic genotypes in Henan Province in recent years and a local circulating prevalence might be established. Continuous and in-depth monitoring of HPIV3 C3 subtype would be of great significance for the prevention and control of HPIV3-associated diseases.