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Friday 12 June 2009

RAPID ROUNDUP: WHO declares swine flu pandemic - experts respond

OTHER ROUNDUPS: June 17 | May 22 | Initial reaction
Also available: Science Blog | Useful links

The World Health Organisation (WHO) has raised the global alert level for influenza A(H1N1) infection to Phase 6, the pandemic phase. Designation of this phase indicates that a global pandemic is under way. This phase is characterised by community level outbreaks in at least one other country in a different WHO region in addition to human-to-human spread of the virus into at least two countries in one WHO region.

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Professor Adrian Sleigh is from the National Centre for Epidemiology and Population Health at The Australian National University in Canberra.

“Pandemic infections are epidemics that are spreading through populations in many parts of the world. They are widespread because conditions were suitable for spread and many people were susceptible to infection. They may or may not be serious infections.

The current H1N1 influenza has been a mild infection in Australia so far. Its pandemicity and its seriousness are separate properties - and so far it is pandemic but not more serious than normal seasonal influenza. In the past other pandemic flu viruses have been more serious than the seasonal variants they replaced; it is too early to say this won't happen again with the current pandemic H1N1 but so far this pandemic strain has been mild in its effects.”

Professor Chris Burrell is Emeritus Professor of Virology at The University of Adelaide.

“The important thing to stress is that this reflects the extent of the global distribution of infection but it says nothing about the severity of it. There still has not been any suggestion that it is becoming more severe and the vast majority of infections have not needed to go to hospital and have not been particularly unwell at all.

In Australia each state sets its own policy and level of containment depending on the number of cases they have got and they set their quarantine requirements for people coming from other areas depending on the particular area they are arriving from. Victoria, with the vast majority of cases, is having to handle this in a different way to South Australia at the moment.

Declaring this a pandemic is a reflection of the global distribution and it may also be a reflection of how far they predict it may spread in a geographical sense around the world but at this point it says nothing about the severity of it.”

Professor Raina MacIntyre is Professor of Infectious Diseases Epidemiology and Head of the School of Public Health and Community Medicine at the University of NSW. She sits on the Scientific Influenza Advisory Group to the Chief Medical Officer of Australia and is an expert in influenza and emerging infectious diseases.

“The WHO definition of Phase 6 is evidence of sustained community transmission in one country in an additional WHO region (over and above the requirements for phase 5). According to this definition, we have technically already been in Phase 6 for a while. The WHO phases, however, are guides rather than absolute rules, and do not factor in severity of the infection. The fact that the epidemic is not as severe as initially feared, as well as trade and economic implications of declaring Phase 6, may also have been factors in the decision. In addition, the question of this being a H1 virus is also relevant - traditional thinking about a pandemic dictates that a pandemic virus has a new H type (eg H5, H7) previously not seen in humans. Swine flu is H1N1, which is not a new H-type, but a severely drifted H1. So whether this meets the definition of a pandemic virus is also questionable. These factors all combine to make the current situation quite complex.

Now that WHO has finally declared Phase 6, it is an indication that nations need to step up their pandemic action plans accordingly."

Dr Vince Hooper is from Banking and Finance at the Australian School of Business, University of New South Wales. He is able to comment on risk influences on emerging markets.

"Sydney has a mountain range of high rise apartment blocks, many with garbage chutes which could be a potential transmission mechanism for the virus if they are not properly and hygienically cleaned frequently. It is important that the Health Department has guidelines for Body Corporates to implement safe and coherent waste removal and hygiene strategies, not only to prevent the spread of the swine virus but also other pathogens. We have to remember this is an airborne transmitted disease and has the potential to cost the Australian economy around 5% of GDP if it really takes hold. According to World Bank figures this pandemic could cost the world economy $3trillion in lost GDP."

Dr Mark Lawrie is President of the Australian Veterinary Association.

“It is important to reemphasise the need for ongoing improvements in biosecurity across human and animal health sectors. Within the veterinary sphere, this is a key focus following recent outbreaks of Hendra virus and equine influenza here in Australia. In respect to Influenza A (H1N1), our recommendations, which have been supported by the pork industry, are to monitor and further improve biosecurity within that industry, to raise awareness of the risk of the infection spreading from humans to pigs and, potentially, vice versa. This will become more crucial as the number of human cases increases.”

“Regardless of the pandemic situation, pork meat, appropriately cooked, canned or cured, is safe for people to eat.”

Professor Nikolai Petrovsky is Research Director, Vaxine Pty Ltd

“The recent establishment and spread of swine flu within the Southern hemisphere (predominantly Australia) having originated in the Northern hemisphere, confirms that swine flu is with humans to stay and thereby satisfies all criteria to be officially listed as a ‘influenza pandemic’. The label of a pandemic does not refer to the severity of the infection but rather its ability to spread throughout the human population of a new influenza strain that has its origins in a non-human species, in this case swine. These influenza pandemic events happen with a periodicity of 20-30 years and each of the current seasonal H1 and H3 influenza strains had its origins in an initial pandemic. The implications are that it is almost certain that the new swine flu strain will join existing H1, H3 and B influenza strains as an indefinitely circulating season human influenza strain.

Given the widespread establishment of swine flu in the human population is now inevitable, the question is now just not whether a monovalent vaccine against the new swine flu strain will need to be developed, but just as importantly should we start thinking about developing a new quadrivalent seasonal flu vaccine incorporating the existing 3 H1, H3 and B strains and in addition the new H1 swine flu strain. Vaxine Pty Ltd, a research organisation based within Flinders Medical Centre in Adelaide and funded by the US National institute of Health has previously successfully developed a quadrivalent vaccine covering H1/H3/B and H5 influenza strains, thereby providing protection against both avian pandemic influenza plus seasonal influenza. The Vaxine team is now applying the knowledge generated in development of the first combined seasonal/pandemic vaccine to develop and test a new quadrivalent vaccine including H1/H3/B and swine H1 strains that could then effectively counter all major flu strains including swine flu currently circulating in the Southern hemisphere and which will inevitably return to cause further disease in the Northern hemisphere when they re-enter their next flu season in six months time.”