Received: 10 January 2019
Accepted: 21 October 2019
First Online: 5 November 2019
Ethics approval and consent to participate
: Study procedures have been reviewed and ratified by the Pasteur Institute Ho Chi Minh City Institutional Review Board (reference number: 02 /PAS-HĐĐĐ). Written informed consent was required for both patients and family members; parental informed consent was requested for minors.
: Not applicable.
: The authors declare that they have no competing interests.