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BackgroundThe resurgence of pertussis has occurred in many countries. However, the epidemiological profiles of pertussis cannot be well understood by the current surveillance system in China. This study was designed to investigate the age specific serologic evidence of antibodies against pertussis, and to offer information regarding the existence of pertussis infection in Zhejiang Province, China.MethodsA cross-sectional serosurvey was carried out in 6 counties of Zhejiang Province during September and October of 2014. The immunoglobulin G-pertussis toxin (IgG-PT) levels were measured quantitatively with a commercially available enzyme-linked immunosorbent assay (ELISA). The antibody activities were expressed in the Food and Drug Administration (FDA)-U/ml and a level ≥30 FDA-U/ml was considered seropositive. An IgG-PT >80 FDA-U/ml indicated recent pertussis infection if the patient had not received immunization with the pertussis vaccine within the last year.ResultsThe mean IgG-PT seropositivity rate among the 2107 subjects was 33.32% with a geometric mean concentration of 17.73 (95% confidence interval: 16.90–18.60) FDA-U/ml. The difference in the seropositivity rates reached significant means among the different age groups (waldχ2 = 198.41, P<0.0005), and children aged 3 years had the highest percentage (63.24%) of undetectable IgG-PT level. Of the 1707 subjects ≥3 years of age, 169 (9.90%) had evidence of a recent infection. The highest proportion of IgG-PT levels ≥80 FDA-U/ml was found in ≥60 years age group followed by 11–15 and 16–25 years age groups.ConclusionsThis study indicates the rather lower IgG-PT level sustained 1 year after the acellular pertussis vaccine booster dose, and substantial proportion of population susceptibility to pertussis in Zhejiang Province, China. Moreover, pertussis infection is not uncommon; it was estimated that 10% of subjects were recently infected approximately within the last 100 days. We highly suggest that the surveillance capacity should be strengthened and consider introducing booster dose that protect against pertussis in 6 years old children.

Objective: To evaluate the cost-effectiveness of the current strategy combining universal vaccination with hepatitis B immunoglobulin (HBIG) treatment for infants of hepatitis B surface antigen (HBsAg) positive mothers compared with universal vaccination with hepatitis B vaccine only. Methods: A decision tree model with a Markov process was constructed and used to simulate the lifetime of the birth cohort in Zhejiang Province during 2016. The current strategy was compared against universal vaccination with respect to costs and health effects. Costs were assessed from the health care system perspective. Health effects were measured by the number of hepatitis B virus (HBV) related diseases and deaths avoided and quality-adjusted life-years (QALYs) gained. The incremental cost-effectiveness ratio (ICER) is calculated and compared to standard willingness-to-pay thresholds. A one-way sensitivity analysis and a probabilistic sensitivity analysis (PSA) were performed to assess parameter uncertainties. Results: Over the cohort's lifetime, 182 acute symptomatic infections, 2215 chronic infections, 872 cases of cirrhosis, 595 cases of hepatocellular carcinoma (HCC) and 1,350 HBV-related deaths among the cohort of 624,000 infants would be further avoided by the current strategy compared to universal vaccination. Universal vaccination was dominated by the current strategy that produced not only higher total QALYs, but also had lower costs. The results remained robust over a wide range of assumptions. Conclusions: The current strategy was cost saving compared to universal vaccination, and continuing the current strategy is recommended to further decrease the burden of hepatitis B.

Background Shifts have occurred in the epidemiological characteristics of Japanese encephalitis (JE), extending from the molecular level to the population level. The aim of this study was to investigate the seroprevalence of JE neutralizing antibodies in healthy populations from different age groups in Zhejiang Province, and to conduct mosquito monitoring to evaluate the infection rate of Japanese encephalitis virus (JEV) among vectors, as well as the molecular characteristics of the E gene of isolated JEV strains. Methodology/Principal findings A total of 1190 sera samples were screened by a microseroneutralization test, including 429 infants (28d-11m) and 761 participants (2y-82y). For those under 1 year old, the geometric mean titers (GMTs) of the JE neutralizing antibody was 9.49 at birth and significantly declined as the age of month increased (r =-0.225, P<0.001). For those above 1-year old, seropositive proportions were higher in subjects aged 1-3 years old as well as �25 years old (65%-75%), and relatively lower in subjects aged between 4-25 years old (22%-55%). Four or more years after the 2 nd dose of JEV-L (first dose administered at 8 months and the second at 2 years of age), the seropositive proportion decreased to 32.5%, and GMTs decreased to 8.08. A total of 87,201 mosquitoes were collected from livestock sheds in 6 surveillance sites during 2015-2018, from which 139 E gene sequences were successfully amplified. The annual infection rate according to bias-corrected maximum likelihood estimation of JEV in Culex tritaeniorhynchus was 1.56, 2.36, 5.65 and 1.77 per 1000, respectively. JEV strains isolated during 2015-2018 all belonged to Genotype I. The E gene of amplified 139 samples differed from the JEV-L vaccine strain at fourteen amino acid residues, including the eight key residues related to virulence and virus attenuation. No divergence was observed at the sites related to antigenicity. Conclusions/Significance Zhejiang Province was at a high risk of JE exposure due to relatively lower neutralizing antibody levels among the younger-aged population and higher infection rates of JEV in PLOS NEGLECTED TROPICAL DISEASES

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