The international science journal Nature has lifted the media embargo on an important paper due for publication next week – The paper raises the possibility that the current prophylactic regimen for Tamiflu (oseltamivir) may have contributed to the emergence of partial resistance to the drug in a Vietnamese patient.
This paper provides an analysis of an H5N1 virus — isolated from a
patient in Vietnam earlier this year (1) – that is partially resistant to
oseltamivir.
The potential emergence of a resistant virus is a continuing concern of
health agencies, although evidence to date suggests that viruses with
mutations giving rise to resistance have reduced fitness, making them less
transmissible and of lower pathogenicity.
The paper highlights the fact that the current recommended
prophylactic treatment regimen may involve suboptimal doses and
durations of oseltamivir treatment that could contribute to the emergence
of resistant virus. It also raises the possibility that a larger arsenal
of influenza antivirals may need to be developed. Stockpiling zanamivir
(sold as Relenza) in addition to oseltamivir may be warranted.
Although the case described in this paper was part of a family cluster,
the paper does not directly address the issue of human-to-human
transmission of H5N1.