Impact of the national hepatitis B immunization program in China:a modeling study

Background:Elimination of hepatitis B virus(HBV)is a striking challenge for countries with high or moderate disease burden.Therefore,using China as a practical case to share experiences for similar countries may accelerate the achievement of the WHO 2030 target of 90%reduction in HBV-related incidence.We aim to evaluate the impact of national HBV immunization strategies in China;and the feasibility to achieve WHO 2030 targets under diferent scenarios.Methods:We constructed an expanded Susceptible-Exposed-Infectious-Recovered(SEIR)model and decision treeMarkov model to estimate the epidemic of HBV in China,assess the feasibility of 2030 Elimination Goals through the projections and conduct the economic analysis.Least square method was used to calibrate the expanded SEIR model by yearly data of laboratory-confrmed HBV cases from 1990 to 2018.Two models were separately used to evaluate the impact and cost-efectiveness of HBV vaccine by comparing prevalence of chronic HBV infections,qualityadjusted life-years(QALYs),incremental cost efectiveness ratio and beneft–cost ratio(BCR)under various intervention options,providing a basis for exploring new containment strategies.Results:Between 1990 and 2020,the number of chronic HBV infections decreased by 33.9%.The current status quo would lead to 55.73 million infections(3.95%prevalence)in 2030,compared to 90.63 million(6.42%prevalence)of the“Without the NIP”scenario(NIP:National Immunization Program),114.78 million(8.13%prevalence)without any interventions.The prevention of mother to child transmission(PMTCT)strategy showed a net beneft as 12,283.50 dollars per person,with BCR as 12.66,which is higher than that of universal vaccination at 9.49.Compared with no screening and no vaccination,the PMTCT strategy could save 7726.03 dollars for each QALY increase.Conclusions:Our fndings proved the HBV vaccination has demonstrated a substantial positive impact on controlling the epidemic of HBV in terms of efectiveness and economy after about 30 years of implementation of the national hepatitis B immunization program which also provided containment experience for high or medium burden countries.As for China,the next step should focus on exploring strategies to improve diagnosis and treatment coverage to reduce the burden of HBV-related deaths and ultimately eliminate HBV.

A Severe Seasonal Influenza Epidemic During 2017–2018 in China After the 2009 Pandemic Influenza: A Modeling Study

Influenza viruses continue to cause epidemics worldwide every year.However,due to the lack of an effective assessment for the severity of influenza epidemics,it was extremely difficult to take preventative measures.Data were extracted from infectious diseases reports from 2011–2018.Joinpoint regression model and susceptible-exposed-infectious-recovered model were built to understand the characteristics and processes of the epidemic.The reported incidence of influenza was 1,913,698 from January 2011 to February 2018,with an average-yearly-reported-incidence-rate of 19.21 per 100,000.However,there had been a substantial nationwide epidemic of influenza after September 2017,when the average yearly reported incidence rate was 87.29 per 100,000 and an annual percentage change of 48.1%.The hemagglutinin genes of most influenza A(H1N1 and H3N2)viruses from the period of the epidemic had lower homology to those before August 2017.All the hemagglutinin of the recommended A(H3N2,H1N1)and B(Victoria)viruses for vaccines 2017/2018 had low matches with the epidemic viruses.The basic reproduction number was 1.53.The vaccination benefit was linearly related to vaccination coverage,while the quarantine measure had only significantly benefited when over 60%of the quarantined population.The most severe epidemic of influenza in China since 2011 occurred during the period from September 2017 to February 2018.Compared to quarantine,influenza vaccination is more effective way to prevent influenza,and strategies to increase vaccination coverage should be taken for the prevention of severe epidemics of influenza.