1. Department of Infectious, Parasitic, and Immune-Mediated Diseases, Istituto Superiore di Sanità, 00161 Rome, Italy.
2. Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, 00161 Rome, Italy.
3. Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, 00161 Rome, Italy.
4. Division of Infectious Diseases, Mount Sinai School of Medicine, New York, NY 10029.
5. Department of Public Health and Medicine, Weill Medical College of Cornell University, New York, NY 10065.