In its latest briefing on the H1N1 influenza A pandemic (swine flu), the World Health Organisation (WHO) says the unprecedented speed of the spread of the virus means reporting requirements and the data needed for risk assessment, both within affected countries and at the global level, are changing.
The WHO says the spread of the pandemic, within affected countries and to new countries, is considered inevitable and unstoppable.
In past pandemics, influenza viruses have needed more than six months to spread as widely and as the new H1N1 virus has spread in less than six weeks, the WHO says 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.
The WHO says 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.
But the WHO says monitoring is still needed for unusual events, such as clusters of cases of severe or fatal pandemic infection, clusters of respiratory illness requiring hospitalization, or unexplained or unusual clinical patterns associated with serious or fatal cases.
This pandemic has been characterized by the mildness of symptoms in the overwhelming majority of patients, who usually recover, even without medical treatment and according to the WHO signs 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 - but a strategy that concentrates on the detection, laboratory confirmation and investigation of all cases, including those with mild illness, is extremely resource-intensive and 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.
The WHO says for these reasons the organisation will no longer issue the global tables showing the numbers of confirmed cases for all countries but regular updates will be provided describing the situation in newly affected countries.
To date Australia is the worst-hit country in the Asia-Pacific region and in the midst of the southern hemisphere's traditional winter flu season, Australia cases have now topped 10,000 but experts warn that the real number could be much higher.
Australia with 10,387 confirmed swine flu cases now has more than 10% of the global total confirmed by the World Health Organization and Health Minister Nicola Roxon says the real number could be much higher, as mild cases are not being tested - the latest tally from the WHO says 94,512 cases of A(H1N1) influenza have been reported, causing 429 deaths but the real number is thought to be much higher.
Ms Roxon says currently 123 people are hospitalised with swine flu and 58 of those are in intensive care - to date swine flu has been linked to the deaths of 20 Australians most of whom had underlying serious health issues - however there is some concern as in a few cases the disease has now started to severely affect otherwise healthy people.
In Britain where there has also been a spike in reported swine flu cases, 29 people have died and the number of new cases is now well over 55,000 and health authorities have promised a National Flu Service by the end of next week to relieve pressure on hospitals and GPs.
The flu service, a part of the government's pandemic contingency plans, will only be available in England, which has been worse hit by swine flu and will be manned by up to 2,000 call centre staff at any one time.
The call centre staff will use a checklist to diagnose whether the person calling has swine flu and will be able to give them a voucher number to get anti-viral drugs if they are believed to be infected.
The British government has warned that deaths from swine flu this winter could be between 19,000 and 65,000 in the UK but experts say it is impossible to predict the death toll.
In the United States President Barack Obama has earmarked $1.825 billion for emergency use to fight the new pandemic of H1N1 swine flu - that money will buy vaccine ingredients and help health officials plan immunization campaigns.
The WHO says at least 50 governments have placed orders for vaccines but one is not expected to be available for at least two months.