1. School of Statistics and Data Science, LPMC and KLMDASR, Nankai University, Tianjin, China.
2. Institute of Mathematical Sciences, ShanghaiTech University, Shanghai, China.
3. Department of Mathematics and Simon Fraser University, Burnaby, Canada.
4. Department of Statistics and Actuarial Science, Simon Fraser University, Burnaby, Canada.
5. Department of Infectious Diseases, University College London, London, United Kingdom.