Should we panic about swine flu?
So how worried should we be?
The death toll in Mexico has risen to 159. In the United States, California has declared a state of emergency and Dr Richard Besser, the acting head of the Centres for Disease Control, has warned there will almost certainly be fatalities.
Here, health officials are waiting for the results of tests on 23 people with symptoms of the disease, and in Europe, Germany is added to the list nations with confirmed cases.
It all reads very much like the start of a pandemic: one we were warned to expect, although the most likely vector was assumed to be poultry rather than pigs.
And yet it remains the case that no one outside Mexico has died of the disease.
That fact offers some hope. It could be that the strain circulating in Mexico is unusually virulent. Or it could be that the total number of cases in Mexico is very much higher. If 10,000 people have caught the flu there for instance, then 159 deaths - bad as that is - does not herald global armageddon.
Good health care, and the anti-viral drugs like Tamiflu and Relenza we've been stockpiling in recent years, should be enough to see us through.
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One troubling scenario remains however. This strain of swine flu does appear to be easily transmitted. If it gets to south-east Asia where the much more virulent H5N1 bird flu is widespread, then we might expect the strains to mix and mutate. That could throw up a highly virulent and easily transmissible virus.
If that happens one of the world's leading experts on the 1918 flu pandemic, Professor John Oxford from Barts and the Royal Hospital London argues, all bets are off.
I'm Tom Feilden and I'm the science correspondent on the Today programme. This is where we can talk about the scientific issues we're covering on the programme. 
Comment number 1.
At 20:45 29th Apr 2009, TalkSwineFlu wrote:I think people need to stay calm, Once people get scared this Swine Flu H1N1 virus could likely spread fast.
https://www.TalkSwineFlu.com
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Comment number 2.
At 07:30 30th Apr 2009, Bill Bradbury wrote:My daughter and partner are out in Mexico and she is in daily contact with me via text. They have been told nothing about the panic over here and as far as the Thompsons' rep is concerned and most of those at the hotel complex, they cannot see what all the fuss is about. She will return on Monday to Manchester as scheduled. They have been told that there are 2 flights to Gatwick and 1 to Manchester on Friday but only 4 are leaving.
As to the "professional help" from the health service my wife rang her practice yesterday to arrange an appointment for Tuesday when she will be home and was told to ring on Friday and it was a Bank Holiday on Monday. My daughter had spent two days in a Hospital on arrival for an entirely different reason than flu and all we want is her checked. She was full of praise for the attention she got over there far better than she would have got here which speaks volumes for our health service!!
So according to my daughter why are we so worried as it must be the media stirring things up? We are obviously are worried and wonder what is really happening and what will happen when they return and how we should react as I teach in a school. Will I be banned from turning up for work as I will be in contact with her? Will she and her partner be allowed back into work? Lots of fuss but no practical advice from the press and media.
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Comment number 3.
At 21:48 11th May 2009, KristinaBrooker wrote:This comment was removed because the moderators found it broke the house rules. Explain.
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Comment number 4.
At 13:24 13th May 2009, bigtonyr wrote:Your point about there may be 10,000 cases of swine flu in Mexico is a good one - I think there must be even more than this:
Assume infection rate among british tourists is the same as that of Mexican population as a whole
111 million Mexicans, something like 1,500 reported cases there = 1 in 74,000 infection rate
30 or so British tourists infected in Mexico x 74,000 = 2,220,000 British tourists in Mexico in last few months - highly unlikely!
So, some combination of the following (or other factors I haven't thought of) is true:
a) British tourists are particularly prone to swine flu
b) Swine flu outbreak in Mexico is concentrated in main tourist areas
c) Mexican authorities are massively understating the number of cases
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Comment number 5.
At 22:18 10th Nov 2009, sigs wrote:I realize some time has passed since this post and clearly things have changed. The Swine Flu is now considered pandemic but the mortality rates aren't what people were expecting. Healthy people are typically getting by with less severe symptoms and it's usually those in high risk groups that are experiencing more severe issues. Doesn't appear to be all that much worse than the regular seasonal flu.
https://www.H1N1GetTheFacts.com
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