title: Authors' reply.
authors.affiliation: Department of Respiratory Medicine, Postgraduate Institute of Medical Sciences, Pandit Bhagwat Dayal Sharma University of Health Sciences, Rohtak, Haryana, India.
authors.forename: Prem Parkash
authors.initials: PP
authors.lastname: Gupta
authors.forename: Sushma
authors.initials: S
authors.lastname: Sood
authors.forename: Atulya
authors.initials: A
authors.lastname: Atreja
authors.forename: Dipti
authors.initials: D
authors.lastname: Agarwal