Pandemic Influenza A (H1N1) 2009 in India: Duration of virus shedding in patients under antiviral treatment

• Published in: Indian journal of medical microbiology Vol. 29; no. 1; pp. 37 - 41
• Main Authors: Gandhoke, I, Rawat, D.S, Rai, A, Khare, S, Ichhpujani, R.L
• Format: Journal Article
• Language: English
• Published: India Medknow Publications on behalf of Indian Association of Medical Microbiology 01-01-2011; Elsevier B.V; Elsevier Limited
• Subjects: Adolescent; Adult; Antiviral Agents - administration & dosage; Child; Child, Preschool; Disease control; Female; Hospitals; Humans; India; Infant; Infection; Infectivity; Influenza A; Influenza A Virus, H1N1 Subtype - isolation & purification; Influenza pandemic; Influenza pandemic, Oseltamivir, real-time polymerase chain reaction, virus shedding; Influenza virus; Influenza, Human - drug therapy; Influenza, Human - virology; Male; Middle Aged; Oseltamivir; Oseltamivir - administration & dosage; Pandemics; Pharynx; Polymerase chain reaction; real-time polymerase chain reaction; Reverse Transcriptase Polymerase Chain Reaction - methods; Risk groups; Swine influenza; Time Factors; Virology - methods; Virus Shedding; Young Adult; India; Influenza pandemic; Oseltamivir; virus shedding; real-time polymerase chain reaction
• ISSN: 0255-0857; 1998-3646
• DOI: 10.4103/0255-0857.76522

Background: National Centre for Disease Control (NCDC), Delhi, is a
national nodal centre for surveillance of pandemic Influenza A (H1N1)
in India. The present study was undertaken to see the period of
infectivity in positive cases undergoing antiviral therapy. Objective:
To assess the duration of virus shedding by real-time polymerase chain
reaction (real-time PCR) in some of the positive patients taking
Oseltamivir treatment. Materials and Methods: Clinical samples (throat
swabs, nasal swabs and nasopharyngeal swabs) collected by the
clinicians from patients quarantined in government hospitals in
different parts of India are being sent to the designated reference
laboratory at Delhi for screening presence of pandemic Influenza virus.
The samples are tested by Real-Time PCR using CDC recommended reagents
and protocol for confirmation of the H1N1 novel influenza virus. In 150
of the positive cases, we requested the clinicians to send samples for
5 consecutive days after administration of antiviral therapy, to see
the trend of therapy response on viral shedding. Samples for more than
5 days were received from patients till they showed no amplification
for any of the three target genes (Influenza A, Swine Influenza A or
Swine H1). Results and Conclusion: In 99.33% (149/150) cases, the
influenza infection resolved within 10 days. Sixty-four percent
(96/150) of the positive patients turned negative within 5 days of the
start of antiviral treatment. Only one patient belonging to high risk
group showed prolonged virus shedding (19 days).