World
Health Organization Stops Tracking Laboratory-confirmed Cases of H1N1 Swine Flu
 | The
World Health Organization (WHO) announced last week that it would stop tracking
laboratory-confirmed cases of H1N1 influenza
and resuling deaths. The number of infected individuals now exceeds 1 million,
and there is little benefit to be gained from testing suspected cases, the organization
indicated. WHO did, however, ask countries to be alert for unusual clusters of
severe or fatal flu cases. |
Below
is a WHO briefing describing the recent decision.
Changes
in Reporting Requirements for Pandemic (H1N1) 2009 Virus Infection Geneva,
Switzerland. July 16, 2009. As the 2009 pandemic evolves, the data needed for
risk assessment, both within affected countries and at the global level, are also
changing.
At
this point, further spread of the pandemic, within affected countries and to new
countries, is considered inevitable. This
assumption is fully backed by experience. The 2009 influenza pandemic has spread
internationally with unprecedented speed. In past pandemics, influenza viruses
have needed more than six months to spread as widely as the new H1N1 virus has
spread in less than six weeks. The
increasing number of cases in many countries with sustained community transmission
is making it extremely difficult, if not impossible, for countries to try and
confirm them through laboratory testing. Moreover, the counting of individual
cases is now no longer essential in such countries for monitoring either the level
or nature of the risk posed by the pandemic virus or to guide implementation of
the most appropriate response measures. Monitoring
still needed This
pandemic has been characterized, to date, by the mildness of symptoms in the overwhelming
majority of patients, who usually recover, even without medical treatment, within
a week of the onset of symptoms. However, there is still an ongoing need in all
countries to closely monitor unusual events, such as clusters of cases of severe
or fatal pandemic (H1N1) 2009 virus infection, clusters of respiratory illness
requiring hospitalization, or unexplained or unusual clinical patterns associated
with serious or fatal cases. Other
potential signals of change in the currently prevailing pattern include unexpected,
unusual or notable changes in patterns of transmission. Signals to be vigilant
for include spikes in rates of absenteeism from schools or workplaces, or a more
severe disease pattern, as suggested by, for example, a surge in emergency department
visits. In
general, indications that health services are having difficulty coping with cases
mean that such systems are under stress but they may also be a signal of increasing
cases or a more severe clinical picture. A
strategy that concentrates on the detection, laboratory confirmation and investigation
of all cases, including those with mild illness, is extremely resource-intensive.
In some countries, this strategy is absorbing most national laboratory and response
capacity, leaving little capacity for the monitoring and investigation of severe
cases and other exceptional events. Regular
updates on newly affected countries For
all of these reasons, WHO will no longer issue the global tables showing the numbers
of confirmed cases for all countries. However, as part of continued efforts to
document the global spread of the H1N1 pandemic, regular updates will be provided
describing the situation in the newly affected countries. WHO will continue to
request that these countries report the first confirmed cases and, as far as feasible,
provide weekly aggregated case numbers and descriptive epidemiology of the early
cases. For
countries already experiencing community-wide transmission, the focus of surveillance
activities will shift to reporting against the established indicators for the
monitoring of seasonal influenza activity. Those countries are no longer required
to submit regular reports of individual laboratory-confirmed cases to WHO. Monitoring
the virological characteristics of the pandemic virus will be important throughout
the pandemic and some countries have well-established laboratory-based surveillance
systems in place already for seasonal influenza virus monitoring. Even in countries
with limited laboratory capacity, WHO recommends that the initial virological
assessment is followed by the testing of at least 10 samples per week in order
to confirm that disease activity is due to the pandemic virus and to monitor changes
in the virus that may be important for case management and vaccine development.
Updated
WHO guidelines for global surveillance reflect in greater detail these recommended
changes, in line with reporting requirements set out in the International Health
Regulations. 7/21/09 Source World
Health Organization. Changes in reporting requirements for pandemic (H1N1) 2009
virus infection. Pandemic (H1N1) 2009 briefing note 3. July 13, 2009. |