Impact of immunization programs on 11 vaccine-preventable diseases in China: 1950-2018

Introduction China’s immunization program has caused dramatic declines in morbidity and mortality from vaccine-preventable diseases (VPDs). To further evaluate the program’s achievements, we explored patterns in the morbidity and mortality of VPDs in China based on national surveillance data. Methods According to the times at which vaccines were introduced and the history of the National Immunization Program (NIP), we divided the study period of 1950 to 2018 into four stages. Meningococcal meningitis, measles, polio, diphtheria, pertussis, tuberculosis, hepatitis B, hepatitis A, Japanese encephalitis (JE), mumps and rubella were analyzed as representative notifiable diseases in China, and annual surveillance data obtained between 1950 and 2018 were used to derive trends in the morbidity and mortality rates of the 11 diseases for each stage. Quasi-Poisson regression models were used to estimate the impacts of specific vaccine programs, and life-table methods were used to calculate the loss of life expectancy, years of life lost (YLLs) and loss of working years. Results The total notification number for the 11 VPDs was 211,866,000 from 1950 to 2018. The greatest number occurred in 1959, with around 12 million cases and a total incidence rate of 1723 per 100,000 persons. The quasi-Poisson regression models showed that most of the 11 diseases revealed dramatic declines in both morbidity and mortality after a vaccine became available. From 1978 to 2018, the incidence of pertussis fell 98% from 126.35 to 1.58 per million, that of measles fell 99% from 249.76 to 0.28 per 100,000, that of meningococcal meningitis fell 99% from 32.23 to 0.01 per million, that of JE fell 98% from 5.39 to 0.13 per million, and diphtheria and polio were eradicated, with the last cases being reported in 2006 and 1994, respectively. From 1978 to 2018, the total life expectancy for the 11 VPDs increased by 0.79 years. Conclusions China has had great success in controlling VPDs in recent decades, and the burden of major infectious diseases has been declining. The implementation of the National Immunization Program accelerated the decreases in the morbidity and mortality rates. Improving vaccination coverage is a key aspect of controlling diseases.