May 04 2009
In 1918 the Spanish Flu (named after the country of origin of the first identified case) swept the globe, killing 20-40 million people – more than the First World War (which killed 15 million) which was just ending. When an epidemic spreads to multiple regions, especially multiple countries or continents, it becomes a pandemic. Flu pandemics happen every 40 years or so, and we are due for one now.
This is probably partly why there has been so much news attention, even some mild hysteria, surrounding recent outbreaks of swine flu, beginning in Mexico. It is hard to say how many cases and how many deaths there have been so far, because information from Mexico is spotty. Specifically it id difficult to say if people who have died with flu-like symptoms really had the swine flu or something else. Estimates are that about 150 people have died in Mexico with the swine flu. It is clear that we are dealing with a new strain.
Some Background on Influenza
But first, a little background. The influenza or flu virus is an RNA virus that comes in three genera – A, B, and C. Influenza A is the most common type. It can infect mammals and birds, with aquatic birds being its natural endemic host. Each year there is a seasonal epidemic of Influenza A, infecting millions of people and killing 100-200,000 – mostly the very old, the very young, and the sick.
Influenza B is less common than A and infects only humans, seals and ferrets. Influenza B mutates slower than A, and so has less genetic diversity and is less virulent as a result. Influenza C infects humans, dogs, and pigs and is the least common type, but can be virulent when outbreaks occur.
All off the pandemics over the last century have been of Influenza A. Its primary weapon is its ability to rapidly mutate, avoiding the immune systems of its hosts. This is why each year new strains of Influenza A are causing that season’s epidemic.
The flu starts out like a common cold, but lasts longer and becomes more severe. It is characerized by high fevers, muscle aches, fatigue, headache, and severe cough.
Influenza A strains are designated by the two main proteins that determine their infectivity and virulencs -haemaglutanin and neuraminidase, H and N. There are 16 Hs but only H 1-3 infect humans, and there are 9 Ns but only 1 and 2 infect humans. Haemaglutanin is a protein that allows the virus to latch onto and infect host cells, while neuraminidase allows expelled viruses to reinfect other cells.
The swine flu virus is Influenza A H1N1. This strain came about probably by four different strains of Influenza A infecting the same host (probably a pig, hence the name swine flu). Viruses can exchange genetic material, so one strain can combine bits from other strains, creating a new strain. The curren swine flu likely combined bits from a human virus, a bird virus, and two swine viruses, although this is still being confirmed.
The flu is potentially a fatal illness, killing about 1% of those infected. Death results from one of three types of causes – the flu infection itself can cause a serious pneumonia (lung infection) that can impair breathing to the point of death. A serious infection can also leave someone open to a superinfection (another organism causing a second infection while the host’s immune system is occupied with the flu). And those who have a chronic underlying illness may succumb from the added physiological stress added by the flu.
Should We Worry
This week on the SGU we interviewed Mark Crislip, and infectious disease doctor, host of Quackcast, and contributor to Science-Based Medicine. We discussed in detail the latest swine flu outbreak, and what level of concern is currently appropriate. The bottom line is this – this is a new strain of flu virus which appears to be spreading. It has the capability of producing a world-wide pandemic, and if it does it could theoretically rise to the level of the 1918 pandemic which killed millions. Some of the reported deaths from Mexico were young healthy adults (which was also common in the 1918 pandemic), which can mean that the strain is virulent.
But it is too early to tell. This epidemic may also fizzle out quickly, ultimately affecting very few. In 1976 there was a swine flu epidemic with concerns that it would be the next big pandemic, but it just fizzled and amounted to nothing.
What determines whether this latest strain with be a bang or a bust is how infectious it is (how many people with catch the virus) and how virulent it is (how may infected people will die from the infection). We do not yet know how this current swine flu will behave – we don’t have enough data points yet. Probably we will not know until the pandemic is underway, or until after it has burnt itself out.
At this point in time there is no reason to panic or make major changes in your lifestyle. The World Health Organization (WHO) and the Centers for Disease Control (CDC) are watching closely and will make recommendations. As of May 3rd the CDC reports 226 laboratory confirmed cases of H1N1 flu and 1 death. At present the CDC recommends the following:
People who are sick are urged to stay home from work or school and to avoid contact with others, except to seek medical care. This action can avoid spreading illness further.
That’s it – they are not recommending that we limit international travel or that we start shutting down schools. Essentially, if you have a cold or flu-like illness, don’t tough it out and go to work – stay home and seek medical care if necessary.
The WHO has similar recommendations. They are not recommending limiting travel at this time. While not explicity recommending the use of masks in public, they also provide guidance as to how to properly use a mask. The same document also details general recommendations to avoid spreading the infection – wash your hands, keep a meter away from symptomatic individuals, stay home if you are sick.
That is where we are today. If the infection continues to spread and show signs that it is developing into a pandemic, the WHO and CDC will update their recommendations.There are some possible signs already that this outbreak will not be the next major pandemic. Mexico just announced that new cases of swine flu are already past their peak. Also, early numbers indicate that this strain is no more infectious or virulent than the usuall seasonal flu strains.
There are treatments for the swine flu. This strain will respond to certain anti-viral drugs, which may decrease the severity of the illness and decrease the mortality. There is currently no vaccine for this strain, and it will take several months to mass produce one. Depending on the timing of the outbreak this may or may not be in time – but if it is a serious outbreak it will likely last several months, so the vaccine will come out toward the end. The role of the vaccine, therefore, may be to shorten the pandemic, but not to avoid it.
The Swine Flu Hubbub
Meanwhile the media has treated the swine flu with near panic. And not just the media – governments and health organizations like the WHO and CDC are stuck between a rock and a hard place. If they overreact to the potential threat then they are accuses of being hysterical. The US government and CDC were soundly criticized for sounding the alarm bells in 1976 when that swine flu amounted to nothing. Yet, if they under-react we could be left unprepared for the next major pandemic. Mark Crislip argued, and I agree, it is better to be a little over-prepared than a little under-prepared.
Already the WHO is being criticized for overreacting to this swine flu. In response WHO officials warn that there could be a second wave of swine flu outbreaks in a month or two – which is what happened in 1918.
It seems silly to play this game – reacting to reactions and then defending with more warnings. Rather, the WHO, CDC, and world governments should plan prudently for a pandemic, and then hope to be wrong.
Another aspect of the hysteria is countries fighting with each other. Mexico is getting a little defensive that travel and exports from Mexico may be restricted – so maybe they are downplaying the number and severity of cases to avoid this. Other countries, even old allies, are bickering over recommendations for travel restriction. Concerns have already been raised that the UK might horde their flu vaccines, leaving the US high and dry.
It seems to me that the purpose of an organization like the WHO is to coordinate international information and efforts to avoid this very type of national bickering in times of a world-wide health crisis. What may be the most worrisome aspect of this outbreak is not the outbreak itself but the response to it. It makes me wonder if we are as ready as I thought we were for such an outbreak. Still I am optimistic – if and when the next big pandemic hits I think the WHO, CDC and similar organizations will rise to the task and do what is necessary. Behind the headlines, their recommendations and actions are all reasonable and prudent.
And, of course, with swine flu grabbing headlines the quacks and cranks have come out of the woodwork to exploit the situation to push their woo and pseudoscience. Offers for snake oil for the swine flu infected spam last week, accounting for 2% of all spam.
The Huffington Post, rapidly becomming the leader of health pseudoscience on the web, has had several recent posts recommending every sort of dubious health treatments and preventions for the swine flu. Orac at Respectful Insolence does a nice takedown of the swine flu woo over at the HuffPo.
And of course the conspiracy theorists have to have their say as well. They can see the Truth behind the hype that the swine flu was manufactured as part of the latest government dark cabal conspiracy to control the world.
At present there is no cause to panic over the swine flu. Yes – this could be a serious outbreak, but we just have to wait and see. So far the early signs are already indicating this will not be a major pandemic, and may already be on the way out. But we still have to watch closely to see which way it will go. The CDC and WHO will be the best sources of information in the coming weeks, while news headlines are likely to be misleading and sensational.
The best recommendations are to take simple and rational steps to avoid getting infected, or if symptomatic to spreading the infection to others.
But even if the swine flu of 2009 proves to be like the 1976 fizzle, eventually we will be hit with another pandemic. For every pandemic there are likely to be a dozen false alarms. The public should not be dismayed by these false alarms nor should they lose faith in the CDC and WHO when early warnings do not pan out. Their job is to keep their eye on early outbreaks, knowing most will not amount to a pandemic, but waiting for the one that will. We need to avoid a “boy who cried wolf” syndrome the press seems intent on manufacturing.
When there is rustling in the bushes it is appropriate to cry wolf, knowing most of the time it will just be a deer or something else. But if we wait until the wolf is at our throats, it will be too late to react.
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