By Nick Triggle
Health reporter, BBC News
Nearly 150 countries have flu contingency plans in place
Experts are adamant, the world has never been better prepared for a flu pandemic.
History tells us that there are global epidemics every 30 to 50 years.
And with the last one happening in the late 1960s, governments across the world have been on alert for the past decade.
That moment could now be here with the World Health Organization describing the outbreak of swine flu as a major concern.
Governments across the world have been revising and making new plans since the re-emergence of bird flu six years ago in south east Asia.
Nearly 150 countries are now known to have drawn up contingency plans covering everything from the response of health services to travel restrictions and international co-operation.
In 2007, the International Health Regulations came into place compelling all 194 member states to respond to a "public health emergency of international concern".
They are required to report results of surveillance activity to the WHO and open lines of communication with other governments.
This is deemed essential in providing good up-to-date information on which decisions can be based to control the spread of disease.
Delay in making the right decisions or even acting too hastily could be costly, WHO believes.
As well as protecting health, the regulations have been drawn up to minimise the impact on global trade and movement.
A worldwide flu pandemic, for example, could cost economies as much as $3 trillion.
It means the WHO feels confident enough to declare that the international community is better prepared than ever.
Keiji Fukuda, who is in charge of health security at WHO, said governments have responded responsibly by stockpiling drugs.
He said: "I think for the immediate period I would say that we are much better off than we've been in the past."
The WHO has praised the UK - along with France - for being the best prepared.
More than 30m courses of anti-viral drugs have been bought - enough to treat half the population.
The drug is not a vaccine, but can lessen the symptoms and minimise spread of the virus.
The UK has also signed a deal with manufacturers to be one of the first in line for a vaccine - this can only be developed once scientists know what strain is behind a pandemic.
The influenza contingency plan was published in 2005 and includes a graduated series of public health measure to control a pandemic.
The NHS and other parts of public sector have carried out exercises to test their preparedness, while the government has powers to impose travel restrictions and screening at ports and airports if necessary.
Professor Stephen Field, president of the Royal College of GPs, said: "The UK has done a really good job. But I would say lots of western governments have invested in this in recent years so there are good plans in place.
"The fears over bird flu have really driven this.
"Because of global travel, a pandemic will get a foothold everywhere so what is important is that the plans that have been drawn up are followed."
WHAT PLANS ARE IN PLACE?
- Nearly 150 countries have flu contingency plans in place, covering everything from hospital and travel to international co-operation
- Many government have also started stockpiling anti-viral drugs, which are not a vaccine but would lessen some of the symptoms. The UK has enough for half the population
- Regulations have been drawn up covering surveillance reporting and communication. The aim is to ensure there is good information available on which decisions can be based
But despite the bullishness of many experts, there are still doubts this will happen.
At the end of last year, the United Nations produced a report warning while many countries had plans in place, too many had not been adequately tested.
Again the UK was congratulated on its response, but just half of those with plans had tested them in the previous 12 months.
Furthermore, just over a third had incorporated lessons from those exercises.
The UN report warned the "continuing lack of preparedness remained a cause for concern".
It added: "It is not enough to have a written plan. You also have to check it, test it and make sure it works and then revise it on the basis of assimilation."
Poor surveillance and lab testing resources were also reported, particularly in Africa.
A global fund has been set up to help support poorer countries - with the World Bank, the US and European Commission big donors.
Their concern is that there only needs to be one weak link in the chain for the best laid plans to unravel.
Sandra Mounier-Jack, an infectious diseases expert from the London School of Hygiene and Tropical Medicine, said: "Countries all over the world have invested significant resources in preparing for an influenza pandemic, notably developed countries.
"However, preparedness levels in middle income and lower income countries remain low.
"The problem is that if you do not have good surveillance and reporting in places where it is emerging you lose valuable time in helping control the spread and understanding the virus.
"There is only a small window and it may already be too late."
What seems certain is that for all the positive noises about preparedness, it will only be when a pandemic actually emerges will we know whether the groundwork has been done right.