1. Department of Virology, Swedish Institute for Communicable Disease Control, Solna, Sweden.
2. Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
3. Division of Experimental Medicine, Department of Medicine, San Francisco General Hospital, University of California, San Francisco, California.
4. Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden.
5. Department of Systems Biology, Center for Biological Sequence Analysis, Technical University of Denmark, Lyngby, Denmark.
6. Department of Medicine, University of California, San Francisco, California.
7. Positive Health Program, Department of Medicine, San Francisco General Hospital, University of California, San Francisco, California.
8. Department of Epidemiology and Biostatistics, University of California, San Francisco, California.