Funding for this research was provided by:
Secretaría de Educación, Ciencia, Tecnología e Innovación de la Ciudad de Mexico (SECITI/115/2017)
Received: 28 February 2020
Accepted: 1 June 2020
First Online: 9 June 2020
Ethics approval and consent to participate
: The study was approved by the Research and Ethics Committees of of National Institute of Respiratory Diseases, Mexico (number of approved C39–14). All participants signed informed consent letter.
: Not applicable.
: All authors declare no potential conflicts of interest.