What exactly does WHO mean by a "pandemic"? Does it mean mass fatalities?
A pandemic is a worldwide epidemic of a disease. It does not necessarily mean mass fatalities. A pandemic refers to how far across the globe the disease has spread, rather than its severity, and as such a pandemic can result in a low fatality count. It may start mild and become severe, or vice versa. It may also start mild and stay that way, or start severe and stay severe.
What does Phase Six mean for countries and communities?
The higher alert does not mean that the virus has become more dangerous. Though in a small percentage of people the illness can become severe and even fatal, in the vast majority of cases the virus causes mild disease.
Countries with no cases yet are advised to remain vigilant, to enhance surveillance, and to be prepared for the arrival of the pandemic. Countries with widespread community transmission should be flexible and calibrate their responses by either moving from containment to mitigation, increasing surveillance and laboratory capacity, and ensuring patients receive prompt care. Countries in transition to community transmission need to fully inform their communities of the threat and about the measures adopted to minimize that threat.
It is normal for communities to be anxious. But they should not overreact. Sensible hygiene practices will offer some protection against the virus. People feeling unwell with flu symptoms should seek medical care, in the knowledge that virus causes mostly mild illness and it is probable they will recover without needing antiviral medication. There will likely be a period of adjustment while the general public gets used to living with this new pandemic.
How severe is this Pandemic?
WHO has classified the current pandemic as being of moderate severity. "Moderate" indicates the pandemic's global impact, not the impact country-by-country.
As such, it should be emphasized that countries may be affected differently – different levels of impact, different timing of outbreaks, different impacts on the economies and health systems. It is important that countries should calibrate their response based on the likely impact in their country
How is the current pandemic different from epidemics such as 1918?
Science has progressed and made the world better equipped to counter a pandemic. In 1918, precautions were not as sophisticated as they are now.
Now we have continual global surveillance of influenza viruses to ensure early detection of unusual outbreaks. WHO has a network or more than 120 National Influenza Centres in over 90 countries to monitor the spread of influenza. Unusual outbreaks are reported immediately, enabling a timely and efficient response.
On the other hand, in some ways the dynamics and interconnections of modern life have made us more vulnerable. Growth in international travel and the increased size of urban conurbations has added to the risk of viruses spreading around the globe faster than in the past.
How long will this pandemic last?
A pandemic doesn't expire after a few weeks. Although it can’t be stated with certainty, a pandemic such as this will last as long as it takes the virus to run its course or a vaccine is found which stops it. Previous pandemics have lasted from 18 months to as long as two years.
Will there be a second wave of this pandemic during winter?
Experience with previous flu pandemics suggest that the current pandemic will become even more widespread in the autumn or winter, causing more illness and death. It is possible that the virus will mutate (change) into a more potent strain at this time.
What is sustained human to human transmission?
This occurs when three generations are involved - i.e. the virus has passed from person A to person B and then to person C.
What is the difference between a probable case and a confirmed case?
A probable case is one that shows the symptoms of influenza such as cough, fever, headache, chills and fatigue and either tests positive for type A influenza or is considered linked to another probable or confirmed case.
A confirmed case is one which tests positive in a laboratory for the Pandemic H1N1 2009 virus.
At what point does WHO consider a pandemic to have started?
Phase 6, as defined by the WHO pandemic preparedness guidelines. However, during both phase 5 and phase 6, national and local actions to respond to the outbreak shift from preparedness to response at a global level. The goal of recommended actions during these phases is to reduce the impact of the pandemic on society.
Related links
Statement by WHO Director-General (WHO Headquarters)
Pandemic influenza preparedness and response (WHO Headquarters)