1. Institute for Infection and Immunity, St George’s University of London, London SW17 0RE, UK
2. State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
3. Department of Ultrasound, Jiangxi Provincial Maternal and Child Health Hospital, Nanchang 330006, PR China
4. Clinical Research Center, Wuhan Medical and Healthcare Center for Women and Children, Wuhan 430016, PR China