So what's the mortality rate for this swine flu ? Why the mortality in the US compared to Mexico just seems low, but isn't

The current outbreak of swine flu is clearly very contagious. It is also clearly very wide spread in Mexico, given the location foreign travellers are coming how with infections from. The two cases in the UK (Scotland) have already created a significant number of other cases of concern.

You hear case numbers mentioned on the radio, but they are very imprecise. Today's radio 4 Today mentioned 2000 cases - but is that current or in total. If its in total then 150 deaths for 2000 cases is a very alarming mortality rate. I assume there are vastly more cases which people have recovered from than are being reported. (Update Reuters have a report of world case number here - if they contain all known cases rather than current cases then mortality would seem to be indicated as high. The Mexican figures suggest 9% - all the figures I've used here are 0.5% - lets pray that in reality the number of mild and unreported cases in Mexico is far higher as we already know its very infectious.)

However if the flue kills about 0.5% of cases ( at the lower end of the 0.5-2% range UK planning seems to think likely ) then there are 30,000 cases in Mexico.

Mexico city has a population of 20,000,000 and the country 109,000,000. That would mean a final casualty rate of 272,500 - ie quarter of a million, assuming 50% of the population get infected.

The UK equivalent is 150,000 fatalities. If mortality is higher or transmission is more effective then that number goes up a lott ( the govt sees 755,000 as its top end projection ). The weak response from the UK government so far, which has consisted mostly of arrogance about being the best prepared country for the coming storm ( now where have we heard that before ? ) does not fill me with confidence.

Given the high amount of medical attention those lucky enough to be the early victims will receive it reasonable to assume mortality can be kept much lower than that initially.

None of this means the virus, which is now in the UK and US is any less deadly than Mexico.

I assume our media's science correspondents are keeping this quiet. But that's a mistake. To avoid panic people need to be assured that their government is levelling with them.

If we are to accept the decisions of doctors and civil servants about who gets treatment or a ventilator and who dies at the peak of an epidemic we need to have trust and faith that they are being open and honest. The alternative is a break down in public order just at the time that the police and military can't cope.

If the mortality rate is 0.5% then given the 40-60 cases identified outside the US we can't really tell anything about the mortality rate, except to rule out ebola type mortality. So far for the chances of a fatality to reach 50%, without medical intervention, would require 138 cases.

This is why the reports of the disease being milder else where are not reassuring.

Finally

Take a look as some pandemic flu (avian) simulations for the US and the expected profile for the UK. What you'll see is a sort of phoney war at the start, until centres of infection spread then the explosion of cases.

Also a typical curve of the profile of an epidemic from the UK govt report "Pandemic Flu" by the Cabinet office.

Update: Sad news for first US death of a child here. That's one fatality in 68 cases. Not enough yet to be statistically sure of large scale outcomes ( this would roughtly indicate a mortality of about 1.4% despite what is presumably very good health care in the US,. If sustained it would be very bad news. The other key issue is transmission rates [unknown currently] ). Cause for concern and a tragedy for their family.


PS My view has now changed from an earlier post. I think this is alarming. Most alarming of all is the thought that the same govt that couldn't control foot and mouth is now going to be responsible for trying to save my family and community.

Shouting fire in a crowded theatre

There are two likely interpretations on the current swine flu outbreak.

1) It an event with high risks, but currently the virus is only causing deaths in Mexico ( and those reports are from the city ). The Authorities are nervous in case theirs a mutation to something more troublesome ( and as the number of human hosts sky rockets the chances of that increase dramatically ). Whilst the death toll of over 100 looks big, its in a city of 20 million people. There will have been a considerable number of other deaths.

Also flights from Mexico haven't been cancelled, which surely would be the case if a high mortality Pandemic was expected. ( Whilst the experts who say the flu can't be contained are no doubt right, it can be delayed giving time for a vaccine to be developed ).

The US has not taken measures that would be required if they saw a clear threat ( schools shut etc ). Update: This is starting to happen and the US has released 25% of its federal reserves of anti-Flu drugs to areas that are likely to be affected.

I wonder if the famous poor air quality in Mexico city has contributed to the deaths. This flu is supposed to be a respiratory disease. Also I wonder if smoking isn't far more common in Mexico?

Hence vigilant but relaxed is the correct outlook.

2) Things are far worse than is being reported. The BBC seems to have a contact in a Mexican hospital who is saying this. Deaths are being hidden as the authorities wish to avoid panic.

Personally I think this is far less likely, though it would be understandable. Its hard to keep a lid on things in the Internet world, I would have thought the BBC should get more sources for their story.

If this is true the lid won't be able to be kept on events for more than a few days, which will then be followed by chaos.

The argument against free speech here is the right to call fire in a crowded theatre case. I think this is mistaken, and trust would be one of the key factors in allowing any government to handle such an epidemic. That trust has to be earned and maintained. If people think they are being routinely lied to then mass panic will be uncontainable. It would be a very bad mistake.

Right now my strong balance of opinion is with 1). Update I'm now leaning more towards 2 based on current information.

Update: Google map of reported cases here - note cases and potential cases in Spain and UK.

This subject has just been covered in some detail on R4's news at one. It makes sobering listening.

Questions are now being asked about why the picture from Mexico is so confused.

Thinking further the fatalities in Mexico rather than the US may be a function of the number of cases. It appears the virus is far more widely present in Mexico than the recorded cases suggest, and hence a low mortality rate would still yield the headline figure of deaths we've seen, but not int he US ( with far fewer current cases ) - and be the same virus.