1 Department of Medicine, Harvard Medical School, Boston, MA, USA; Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA 02215, USA.
2 Division of Infectious Disease, Brigham and Women's Hospital, Boston, MA, USA; Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA 02215, USA.
3 Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA 02215, USA. Electronic address: hao_yu@hphci.harvard.edu.