  COVID-19 vaccines have proven to be effective against SARS-CoV-2 infection.
However, the dynamics of vaccine-induced immunological memory development and
neutralizing antibodies generation are not fully understood, limiting vaccine
development and vaccination regimen determination. Herein, we constructed a
mathematical model to characterize the vaccine-induced immune response based on
fitting the viral infection and vaccination datasets. With the example of
CoronaVac, we revealed the association between vaccine-induced immunological
memory development and neutralizing antibody levels. The establishment of the
intact immunological memory requires more than 6 months after the first and
second doses, after that a booster shot can induce high levels neutralizing
antibodies. By introducing the maximum viral load and recovery time after viral
infection, we quantitatively studied the protective effect of vaccines against
viral infection. Accordingly, we optimized the vaccination regimen, including
dose and vaccination timing, and predicted the effect of the fourth dose. Last,
by combining the viral transmission model, we showed the suppression of virus
transmission by vaccination, which may be instructive for the development of
public health policies.
