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Monday 27 April 2009 (Updated Tue 12 May 2009)

RAPID ROUNDUP: Influenza A H1N1 (Swine flu) initial outbreak – experts respond (April 27)

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An outbreak of swine influenza A(H1N1) that has reportedly caused a number of deaths in Mexico and is rapidly spreading to other countries is causing concern in Australia as we head into the winter flu season. Below Australian experts comment on the strain of flu and what precautions can be taken to help prevent it taking a foothold here.

30 April update: It is now apparent that the 2009 influenza A (H1N1) virus currently circulating in humans, though genetically linked to swine influenza viruses, has not been found in pigs and that pigs do not appear to be involved in the ongoing epidemic. For this reason the World Health Organisation will now refer to the new influenza virus as influenza A(H1N1).

Feel free to use these quotes in your stories. If you need assistance tracking down an expert, please don’t hesitate to contact us on (08) 8207 7415 or by email.

Read comments from:

Professor Robert Booy, Head of Clinical Research at the National Centre for Immunisation Research & Surveillance (NCIRS) based at the University of Sydney.

Dr John Carr, a Pig Veterinary Specialist and senior lecturer in intensive agriculture at Murdoch University’s Dept of Production, Animal Health and Medicine in WA. He is also a key contact at Portec Australia, which promotes the welfare and wellbeing of pigs.

Peter Doherty, a Laurette Professor at the University of Melbourne's Department of Microbiology and Immunology and shared the 1996 Nobel Prize for Medicine.

Dr Danilla Grando, a hygiene expert and Lecturer in Clinical Microbiology in the School of Applied Sciences at RMIT University in Melbourne. Her research focuses on community hygiene and how improving public hygiene habits can help prevent the spread of infectious diseases.

Dr Mark Lawrie, President of the Australian Veterinary Association (AVA) based in Sydney.

Professor Raina MacIntyre, 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.

John Mackenzie, Professorial Fellow at Curtin University of Technology in Perth and is attached to the Biosecurity CRC for Emerging Infectious Disease.

Professor Nikolai Petrovsky, an Adelaide based clinician and vaccine researcher.

Professor Beverley Raphael from the University of Western Sydney’s School of Medicine, heads a specialist research unit which tackles the mental health issues associated with adversities such as disasters, terrorism and pandemic influenza.

Professor Bill Rawlinson from the University of New South Wales. He also works in the Department of Virology at the Prince of Wales Hospital in Sydney.

Professor Mark von Itzstein, director of the Centre for Glycomics at Griffith University in Queensland. He played an instrumental role in the development of the antiviral drug, Relenza, now used globally to treat flu.

The University of NSW's Australian School of Business has collated a range of other comments on the potential economic impacts of the swine flu outbreak including impacts on financial markets and investor behaviour, social and economic impacts, risk management and scenario planning.

Professor Robert Booy is Head of Clinical Research at the National Centre for Immunisation Research & Surveillance (NCIRS) based at the University of Sydney.

ISSUED: 1 May 2009: “There’s been a lot of confusion and consternation over why all the deaths seem to be in Mexico or happening to Mexicans. In fact, there’s probably a simple explanation. In Mexico, it’s likely that this outbreak has been running for not one month or even six weeks, but more than eight weeks. Even if it’s only been running for eight weeks and started with one case, influenza tends to, on average, infect two people for every one case. The doubling then occurs every three days, which is the serial interval. This means that from day one to day 30 you go to about 1000 cases, but in the next month, you go to a million.

If you believe that there’s been hundreds of thousands of cases already in Mexico, then to have seen only about 100 deaths amounts to less than 0.1 % fatality rate, less than one in 1000. So the disease may not be nearly as severe as people thought. If the disease has been around for two months and infected so many people, many of them must be mildly infected and we haven’t heard about them.”

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ISSUED: 27 APRIL 2009: "At this time, although the swine influenza outbreak in Mexico is being taken very seriously both locally and internationally, there remains considerable uncertainty about many things but considerable reason for optimistic caution in Australia.”

Will a pandemic result?
“Quite possibly - time will tell and quite possibly we will know very soon. However, even if or when a pandemic (or worldwide outbreak) occurs, it will not be like the big killer, the Spanish Flu, that accounted for over 50 million people in 1919/1920. We are just so much better prepared this time. We have highly effective drug therapy and also the wherewithal to produce a vaccine. Intensive care is light-years more advanced and we understand so much better the value of simple measures like hand-washing, mask use, avoidance of crowds and quarantine.”

What is the virulence of the organism and hiow likely is it to transmit between humans?
“We need more information. Reports from Mexico suggest this is a nasty bug but it is unclear as yet how well it can spread between humans.”

Are most cases occurring in young people similar to the Spanish pandemic after World War 1?
“We just do not know, but if that were the case, it may indicate that older people have immunity from previous influenza infections providing them protection. Alternatively and perhaps additionally, influenza may also be prominent in young people and children simply because they mix so much more at schools, universities, parties, sports events and so on.”

Will routine influenza vaccination provide any cross cover?
“One would hope so and it may make the difference between falling ill and perishing but for now we can only hope for this. The best guess is that immunity from a prior influenza infection or vaccination is unlikely to prevent acquisition of infection and flu symptoms. Those at high risk of seasonal influenza such as the elderly, pregnant women and those with chronic medical conditions (eg of heart, lung, liver or kidneys) should ensure they have had the annual influenza vaccination.”

Although the organism is so far susceptible to modern anti-viral therapy with either Zanamavir or Oseltamivir, might resistance be induced?
“This is unlikely - previous swine flu isolates have been sensitive to the neuraminidase inhibitors. Australia is fortunate in both having a large local stockpile as well as the capacity to manufacture Zanamivir (an Australian discovery) here.

The apparent high death rate in Mexico seems at odds with the mildness of cases reported from the US?
“This is however entirely consistent with the notion of the case fatality rate in Mexico of about 5%: because with only about 20 cases in the US, the one in 20 death rate may not yet be evident.

More importantly, one would expect a much lower case fatality rate anyway in the USA; cases there generally present earlier to medical care and then receive, on average, a higher quality of care. What's more with better nutrition and social conditions in the USA, this may also account for milder disease.

Pandemic planning has been a major 'whole of government' issue in Australia for more than five years with close cooperation between Commonwealth and jurisdictions. This 'joined-up thinking' has included business, education and other sectors. The stockpile of antivirals in Australia is on a par with the best in the world - and we know how to get the drugs to the frontline.

For now it is important to be diligent, with heightened surveillance for cases at community and hospital levels, to take common-sense precautions and to seek medical attention for severe symptoms of flu like high fever, cough, and muscle aches, while continuing to manage mild sniffles and colds at home. We are one of only 10 countries in the world that can manufacture onshore a new influenza vaccine against a pandemic strain and this can achieved in as little as 8-12 weeks, so although vaccination will not be a first phase issue, we have it in reserve.”

Dr John Carr is a Pig Veterinary Specialist and senior lecturer in intensive agriculture at Murdoch University’s Dept of Production, Animal Health and Medicine in WA. He is also a key contact at Portec Australia, which promotes the welfare and wellbeing of pigs. ISSUED 4 May 2009

What are the chances that this virus could in some way combine with H5N1 creating an easily-transmissible strain with a high mortality rate?
“Unlikely. The H5N1 has only rarely got into pigs. In people it kills quickly leaving little time for reassortment. All things are possible, but all the different ‘flu’ types are available in birds and yet new ‘flu’ viruses in mammals – pigs, horses and man are rare.”

Presumably it is fortunate that this pig strain arose on the other side of the world from where H5N1 arose?
“Probably no real impact. H1N1 is in Asia – it is an extremely common virus of pigs and Asia buys pigs from the North America and Europe both which have H1N1 viruses – although often quite different viruses when they are taken apart. On the other hand pigs which are sick are rarely sold for breeding stock and transported round the world and even then they are placed in isolation.

From an Australian point of view there are no live pig imports of any kind (for over 30 years) and only fresh meat is imported and the risk of influenza through this is minima/nil. Of course the pigs could become infected from people – see Canada. Measures have been advised by the APL and local associations to minimize this risk. In the short term these measures will work, in the long term when people’s memories fade – then perhaps the risk is greater.

Can you comment on the idea that these potentially devastating zoonoses are the inevitable consequences of poor animal husbandry and unsanitary farming practices?
“No impact of ‘modern farming practices’. The influenza virus of 1918 got into pigs soon afterwards and became the H1N1 virus of pigs. The farming of the 1920/30s was very different from today. Today’s system of biosecurity etc is much more enhanced than before. The farms are larger, so respiratory pathogens have more animals to get at, but with influenza if a pig farm got the problem, properly managed it is a two week problem and then the virus dies out with minimal loss of pigs. Today’s farming practices are much cleaner than before, but the pigs would still be vulnerable to flu. Indoors or outdoors, large or small – the chance of the farm becoming positive is a reflection of biosecurity rather than anything to do with the pig. Australia would have an interesting problem with its extensive feral boar population. Currently Australia remains swine influenza free – despite influenza in people and birds. Note the horse flu was also controlled with good biosecurity.

About viruses in general: I am assuming that a 'successful' virus is one which manages to transmit easily without seriously incapacitating or killing its host thus limiting its chances to spread and replicate. A strain which is easily transmitted and extremely virulent (like Ebola) presumably won't get far because its carriers will die before they get a chance to pass it on. Is this the case? And if so how does it fit in with what we know about this and other pandemic-candidates?
“Influenza viruses can spread before they kill their host. In this case the virus appears to not kill too many people – but it spreads quickly.”

Is swine flu any more dangerous than normal flu or does it just sound scarier?
“Influenza has been around a long time – this name is not relevant to it. It has changed enough to evade the human and pig immune system. It will spread, and once it has gone through the population will be immune for life. Of course new humans (babies) and pigs (piglets) come along to continue to provide new hosts. The next couple of weeks will be the teller once the Southern Hemisphere gets into its normal ‘flu’ season. Perhaps this will just add a new complication factor rather than be the pandemic killer we are also so concerned about. We should also remember that this flu has actually little to do with pigs – especially as the only confirmed case in pigs came from contact with people.”

Peter Doherty is a Laurette Professor at the University of Melbourne’s Department of Microbiology and Immunology and shared the 1996 Nobel Prize for Medicine. Here he answers questions from journalists. ISSUED 1 May 2009.

What are the chances that this virus could in some way combine with H5N1 creating an easily-transmissible strain with a high mortality rate?
“Possible but highly unlikely, unless it gets into Indonesia or somewhere and goes back into birds.”

Presumably it is fortunate that this pig strain arose on the other side of the world from where H5N1 arose?
“Yes, though I don’t know that H5N1 has gone into pigs they might both go into cats.”

Can you comment on the idea that these potentially devastating zoonoses are the inevitable consequences of poor animal husbandry and unsanitary farming practises?
“I think they’re more to do with having large numbers of animals and humans close together in warm climates in what we might think of as ‘peasant’ agriculture. Overall, considering food security and the need for very poor people to have meaningful work, I’d be totally opposed to moving animal agriculture more into centrally controlled agribusiness.”

Do you know how many countries have pandemic preparedness plans and what the global stocks of antivirals look like in different countries.
“You’re seeing the US pandemic preparedness campaign working with the school district closures. A lot of this has been handled at the state and/or municipal level. I’m told that Switzerland and the US both have enough H5N1 vaccine for national coverage, though I don’t know about Tamiflu and there would have to be real concerns re the rapid emergence of Tamiflu resistance....Relenza may be a better bet.”

Is swine flu any more dangerous than normal flu or does it just sound scarier?
”We don’t know yet but, as I recall the H1N1 A/Brisbane killed some babies and was generally bad. From what I’ve heard so far via the media, I also wonder whether the current (or past) H1N1 vaccines aren’t conferring some measure of protection.”

Dr Danilla Grando is a hygiene expert and Lecturer in Clinical Microbiology in the School of Applied Sciences at RMIT University in Melbourne. Her research focuses on community hygiene and how improving public hygiene habits can help prevent the spread of infectious diseases. ISSUED 27 April 2009.

“Research has shown that one of the most powerful weapons against the spread of respiratory illness, including any strain of influenza, is simply improving your hand hygiene.

We know that contact transmission is one of the key ways that people become infected by influenza. While flu is an airborne virus, people often fall sick from touching something that carries the influenza germs and then putting their hands in their mouths, often while eating.

Always washing your hands before meals is vital but using an alcohol-based hand sanitiser throughout the day is also extremely effective, and an essential tool in helping to prevent the spread of influenza.”

Dr Mark Lawrie is President of the Australian Veterinary Association (AVA) based in Sydney.

ISSUED 1 May 2009: "We don’t know at this stage where this disease has come from. Throughout history new diseases have emerged and caused problems for people."

"There will always be new zoonotic diseases coming from many animal sources including wildlife – monkeys, bats, civets, and insects. Climate change and habitat destruction increase risk as the boundaries between wildlife, domestic animals, and humans continues to change. Domestic animals and humans themselves can also be sources of new diseases."

"Poor hygiene and bad husbandry practices may increase risks of disease in both intensive and more traditional farming systems. The standards on pig farms here in Australia are high and our pigs are free of many diseases common in other countries, including all forms of Swine flu."

"It is not clear that intensive farming systems are of greater risk than more traditional forms of animal husbandry. If there were, we should have seen more pandemics since intensive farm systems were established. The opposite has been the case."

"The biggest risk for a world pandemic is the amazing mass movement of people due to air travel."

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ISSUED 27 APRIL 2009: "The AVA is not concerned about an outbreak of swine flu among pigs here in Australia. Australia doesn’t import any pigs, so we’re not worried about animals getting sick or spreading this disease. We also don’t import any pig meat from Mexico.

“People should have no qualms about going ahead and eating pork. Pork continues to be safe to eat. In any case, the swine flu virus is inactivated as soon as the meat reaches 70° Celsius during cooking.

"The real concern is human to human transmission by those who have visited a country with an outbreak. Swine flu is spread by skin to skin contact, so washing hands is going to be much more effective than a face mask.

“This outbreak firmly underlines the need for a One Medicine approach to global disease threats where animal and human health professionals work hand in hand. Around 70% of emerging diseases are capable of infecting both animals and humans. We need to work closely together to research and respond to threats to human and animal health."

Professor Raina (pronounced “r-i-nah”) 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. ISSUED 27 April 2009.

“The outbreak of swine flu in humans has come as a bit of a surprise because everyone has been concerned about avian influenza being the source of the next pandemic. The other interesting point is that it’s H1N1 which is not entirely a new strain of influenza to humans. The 1918 pandemic was H1N1 and we’ve had different types of H1N1 circulating in humans ever since. Normally a pandemic is caused by a major antigenic shift which is when an H type shifts to a completely new type that has never been seen in humans before, for example an H5 or an H7. But in this case it’s an H1 which has been seen in humans before, but it is sufficiently different to be of concern and could cause a pandemic. This strain is a re-assortment of human, avian and swine strains of influenza.

Last year the majority of H1N1 seen in the world was resistant to antivirals such as Tamiflu, which is out first line of defence. But it appears that this H1N1 is sensitive to antivirals, which doesn’t mean that resistance couldn’t occur. There seems to have been a high fatality rate in Mexico which is of concern and there’s obviously been a fairly rapid spread to other countries including the US, NZ and possibly France, Chile etc.

There are already efforts underway to produce a matched vaccine. The seasonal vaccine that’s currently available now probably won’t give substantial protection against this strain of flu. It might give small degree of protection that might make the difference between dying from this infection and not. The delay in making the matched vaccine available will be a minimum of eight weeks and possibly up to three months or more. This will take us well into the Australian Winter where we will not have a matched vaccine. In one month we will be right in the Australian winter and it will become more of an issue for us than for the Northern Hemisphere where they will be going into their summer. There are other measures that are really important in that time.

Without a matched vaccine it will be important for people to use all other protective measures that they can, such as masks. My research shows that masks can protect against respiratory viruses. Other measures include hand washing, social distancing (avoiding crowded places etc), being careful when looking after sick people, using tissues when sneezing or coughing and disposing of the tissues immediately etc.”

30 April 2009: Check out Professor MacIntyre's comments on face masks on the UNSW website.

27 April 2009: Professor MacIntyre speaks about face masks on UNSW TV (YouTube)

John Mackenzie is Professorial Fellow at Curtin University of Technology in Perth and is attached to the Biosecurity CRC for Emerging Infectious Disease. ISSUED 27 April 2009.

"The virus in the American cases has been isolated and several have been fully sequenced and the virus appears to be a novel swine influenza-like virus which means its very similar to human viruses except it has sequences indicative of isolates from pigs. They seem to have genes from different viruses - at least two different swine viruses and also an avian virus gene – an unusual virus and not one we’ve seen previously.

It appears to be sensitive to the drug Tamiflu but I suspect that the current vaccine will not be able to provide protection. It is obviously of concern with the big outbreak in Mexico and cases in the US, and there’s also some suggestion that it might be now also in other countries but the evidence is still a little suspect and we haven’t had definite confirmation that its in either the UK, France or NZ as has been suggested.

I guess we’re at that 'grey' stage where we don’t know if it is going to be a pandemic strain or not. We’re certainly concerned but at the same time Australia is in a better position than most other countries to be able to withstand or cope with a pandemic. We have good stockpiles of Tamiflu here, we have an excellent surveillance system in place and we have good diagnostic laboratories. This has largely been due to the avian flu concerns of the last three or four years this had made countries sit up and take notice and develop pandemic preparedness plans, so in a sense we’re well off in being more prepared than previous pandemics. The next 48 hours will tell us what’s going to happen whether there will be pandemic strain or not.

We really do need to know more about transmissibility of the virus in Mexico, whether the virus causing the Mexican outbreak and the one in the United States are the same virus or not. We also don't know enough about the virulence of the virus both in humans and in experimental animals, particularly with the different epidemic pattern in Mexico and the US, and we need to know whether or not the current vaccine will give any protection, although I suspect it will not.”

Professor Nikolai Petrovsky is an Adelaide based clinician and vaccine researcher. ISSUED 1 May 2009.

“The National Institutes of Health (NIH – US Govt) have now agreed to refer to the virus as 2009 H1N1 to distinguish it from seasonal H1N1. Mortality rate appears likely to be similar or maybe slightly higher than normal seasonal flu. Major difference is that in any one year only 6% of the population get seasonal flu as most of the community other than very young and very old have some degree of immunity. This is the reason why deaths from seasonal flu are concentrated at age extremes. With a new virus like 2009 H1N1 no-one in the community is likely to have immunity and therefore we can expect more cases including deaths in healthy young adults, a population not normally at major risk of seasonal flu.

The actual individual source of this particular virus will probably never be exactly know, although it seems likely to have arisen in rural Mexico and a recombination event in forming this new virus must have occurred in a pig. The 2009 H1N1 has a combination of swine, avian and human RNA strands and given that pigs are one of the few hosts susceptible to both human and avian viruses they are known to serve as a mixing vessel for creation of new mixed viruses. It is likely therefore that a pig has almost certainly acted as the host in which this new virus has been created. In order for a pig to simultaneously get infected with human and avian influenza, and then transmit the new virus back to humans, poor animal husbandry would increase the risk of this, although the same scenario could still happen in a modern swinery given that humans and pigs still come into contact in these situations although maybe not as closely, making the multiple transmission events required much less likely.

A successful virus can be associated with a very high mortality rate providing that the virus doesn’t kill the host until such time as the host has managed to transmit the virus to others. Thus providing the virus took say three weeks, rather than a few days to kill the host this would still allow it plenty of time to spread and still be successful. Hence high viral success and high mortality are not unfortunately necessarily mutually exclusive.

Little has been said in Australia about vaccine strategies to prevent 2009 H1N1. US and European manufacturers are currently gearing up to produce vaccine against this strain. Indeed our US collaborators Protein Sciences Corporation anticipate having their first vaccine supplies available within the next few months. Australia is poorly prepared for this pandemic from a vaccine standpoint because after an initial Federal government mandated flurry of one year funding for pandemic vaccine projects by NHMRC in 2006/2007, many of these successful projects have been denied subsequent funding by NHMRC. Lack of funding for these pandemic vaccine projects by NMHRC is not in the interests of ordinary Australians who may otherwise have benefited from better influenza vaccines but is beneficial to the commercial interests of CSL by assisting CSL to retain an effective monopoly on local influenza vaccine development and manufacture. The NHMRC need to explain their refusal to fund these important influenza projects given their brief is meant to be to fund research to better protect the Australian population against threats such as we currently are facing. Given the NHMRC’s failure to prepare Australia for the current threat, there should be a formal government enquiry into the NHMRC and the appropriateness with which it currently administers and allocates public research funds.”

Professor Beverley Raphael from the University of Western Sydney’s School of Medicine, heads a specialist research unit which tackles the mental health issues associated with adversities such as disasters, terrorism and pandemic influenza. ISSUED 27 April 2009.

"Research shows that most people handle adversities well. They seek health and other information if concerned and in this case should note the information being provided by the Australian, state and territory governments.

“For the vast majority of the population recent research shows if the risk of a flu outbreak does increase, Australians are very willing to comply with calls to be vaccinated, isolated or quarantined and wear face masks and take necessary steps to protect and help themselves, their families and others.

"Studies have shown that the majority of people will respond positively and well should any health threat occur such as a new form of influenza. Numerous studies of human behaviour in the face of such threats have shown that people are altruistic, respond positively to health requirements, and even though they may be concerned for themselves and loved ones, do not panic."

Professor Bill Rawlinson is from the University of New South Wales. He also works in the Department Of Virology at the Prince of Wales Hospital in Sydney. ISSUED 27 April 2009.

“There appears to be a spectrum with swine influenza ranging from Mexico where there have been a significant number of deaths to elsewhere where it has presented as a relatively minor illness. There is clearly a spectrum of illness occurring, but it’s still not clear how virulent swine influenza is going to be and we will need to collect more evidence over time.

The availability of heightened surveillance means that this has been identified quite quickly and gives us significant early information – that’s a good thing.

It is very important to say that we have learnt a lot of lessons from avian flu and SARS, but that each outbreak is different and this one needs to be dealt with on its own merits.

Though the systems in place will be extremely useful the clinical nature of the swine influenza outbreak and the outcomes for patients need to be monitored very closely. In dealing with the swine influenza, we can use some of the same systems that we have in place but this should not blind us to the fact that this is a different virus that has arisen in different ways and we still have to learn about what the spread of the virus is likely to be, what forms of treatment will be needed and the utility of vaccination.”

Professor Mark von Itzstein is director of the Centre for Glycomics at Griffith University in Queensland. ISSUED 27 April 2009.

“With the arrival of swine influenza out of Mexico and possibly into New Zealand and indeed into other countries, obviously it’s going to be of concern to Australia and it’s very pleasing to see that we've had a response immediately from our Federal Government to put in place certain alerts at hospitals and now GPs to keep information flowing.

I think it is concerning to see a virus like this emerge that we know something about but certainly not everything, and right now of course we wait and see what happens in terms of further progression of the virus right around the world and in particular whether it does reach our shores, and the most likely way that that would occur is by human travel - by ship or by air travel.

In the context of how it can be transmitted it’s obvious now to us that human to human transmission appears to be a significant pathway, that is this virus has acquired the right machinery to transmit human to human.

The concern of whether one can get it eating contaminated pork shouldn't be a major issue because clearly what we do is we cook our meats and as long as the meat is appropriately cooked it won't be problem. With cured pork it is also highly unlikely as the production cycle that these things go through is significant and usually eliminates any viral or bacterial contamination. I'd be much more concerned about it arriving through humans at airports or on ships.”

Further comment from Professor von Itzstein can be found on the Griffith University website.