Background To allow a return to a pre-COVID-19 lifestyle, virtually every country has initiated a vaccination program to mitigate severe disease burden and control transmission. However, it remains to be seen whether herd immunity will be within reach of these programs. Methods We developed a compartmental model of SARS-CoV-2 transmission for China, a population with low prior immunity from natural infection. Two vaccination programs were tested and model-based estimates of the immunity level in the population were provided. Results We found that it is unlikely to reach herd immunity for the Delta variant given the relatively low efficacy of the vaccines used in China throughout 2021 and the lack of prior natural immunity. We estimated that, assuming a vaccine efficacy of 90% against the infection, vaccine-induced herd immunity would require a coverage of 93% or higher of the Chinese population. However, even when vaccine-induced herd immunity is not reached, we estimated that vaccination programs can reduce SARS-CoV-2 infections by 50–62% in case of an all-or-nothing vaccine model and an epidemic starts to unfold on December 1, 2021. Conclusions Efforts should be taken to increase population’s confidence and willingness to be vaccinated and to develop highly efficacious vaccines for a wide age range. Supplementary Information The online version contains supplementary material available at 10.1186/s12916-022-02243-1.
【저자키워드】 COVID-19, delta variant, herd immunity, Vaccination program, SLIR model, 【초록키워드】 Efficacy, Vaccine, vaccination, Immunity, SARS-COV-2 infection, vaccine efficacy, Infection, Transmission, delta variant, China, Epidemic, SARS-CoV-2 transmission, Coverage, herd immunity, age, compartmental model, estimate, natural infection, SARS-CoV-2 infections, natural immunity, severe disease, the vaccines, supplementary material, return, Chinese, mitigate, country, Result, tested, lack, develop, unlikely, provided, initiated, reached, reduce, the vaccine, 【제목키워드】 SARS-CoV-2, Epidemics, China, Vaccine-induced immunity,