Although the most notable
outbreak of the swine-flu peaked in 2009, the reports regarding the virus and
its treatment have continued to make headlines in mainstream media. A few days
ago, researchers in Australia presented findings that indicated that a cluster
of virus samples showed that it was resistant to oseltamivir in around 10% of
cases in New South Wales. Oseltamivir is the active ingredient in Tamiflu.
These findings were presented at
the Annual Scientific Meeting of the Australasian Society for Infectious
Diseases. The emergence of this resistant strain of this virus, which is called
H1N1pdm09, gave rise to several
concerns among public health experts. The first concern came from the fact that
this virus was found in the community, rather than with sick patients who had
pre-existing conditions, which resulted in a weak immune system. This implied
that the concern for the spread of the virus would not only be for particularly
vulnerable patients, but also for healthy individuals. The second concern came
from the fact that the H1N1pdm09 had spread to individuals who had never been
treated with Tamiflu. This indicated that the virus could spread quite
effectively from one person to another even if there is an oseltamivir
intervention. The final concern, which was never stated by researchers, but has
been noted in mainstream media, was the controversy regarding the efficacy of
Tamiflu that had been reported in the last 12 months.
We were not surprised to read
about a treatment resistant virus developing, as it has happened in the past
with other diseases and treatments. Adamanatane was used to treat influenza but
this is now largely obsolete for this purpose following a development of
resistance. However, we were surprised to see that not all the reports had put
the findings into context. The Australian researchers reported that they had
found this to affect two per cent of their study sample, and a total of eight resistant
cases were confirmed in the UK to date. Naturally it could be argued that these
numbers are concerning, however they are far from alarming. Similarly, while it
is important not to underestimate a new resistant strain of the virus, this
strain is just one of many viruses that are circulating. This is in stark
contrast to how it was when the swine flu was the dominant virus in 2009. Perhaps
the most encouraging news was the fact that although H1N1pdm09 appears to be
resistant to oseltamivir, other reports suggested that the same virus might be
sensitive to zanamivir (which is the active ingredient in Relenza). Relenza
operates in a different way from Tamiflu (even although it also disables the
influenza virus through neuraminidase inhibition).
We feel that once these findings
have been put into context, they show a more realistic version of the
implications of this new virus. The importance of monitoring the spread of new
viruses and strains of viruses is understandable, but our interpretation of the
findings to date suggests that it is too early to be alarmed by these reports. The
really scary flu virus is H5N1. If that started to pass from human to human in
meaningful numbers then we may have a very serious problem.