zpo2, that's an interesting webpage that I haven't seen before. For those not interested in clicking on the link, it basically discusses the link between Vitamin D (a deficiency of it, actually) and infectious disease or general health, too.

Believe me, I have been interested in this recent surge in Vitamin D research, but I think the jury is still out. We are truly still scratching the surface of a whole world of processes that vitamin D is involved with. Vitamin D (which really shouldn't be called a vitamin, like the way Pluto isn't really a planet anymore) acts like a powerful hormone and turns on and off the expression of hundreds of genes and modifies the expression of thousands.

There is a lot of interest in Vitamin D among scientists and it is exciting stuff, but I think it's very important to also listen to alternative opinions when so little is still known. The prevailing paradigm that has recently emerged is that we humans have been vitamin D deficient in the developed world and that this lack of vitamin D is causing various diseases of modern living.I have provided the link to one essay below which cautions us not to wholeheartedly jump on that paradigm just yet.

It is a scientific article and a difficult read, but an important one IMHO since you don't see many alternative opinions to the prevailing paradigm. The link is to a pre-print version but it appears to be the same as the actual published article that I have read. You don't even have to go to a university library to read it!

Marshall TG: Vitamin D Discovery outpaces FDA decision making.
BioEssays Volume 30, Issue 2, Pages 173-182, February 2008
http://trevormarshall.com/BioEssays-Feb08-Marshall-Preprint.pdf

There very well may be a link between vitamin D and pandemics. I'm not totally pooh-poohing that idea. I'm just saying that we still need to keep an open mind about vitamin D and its role in health since we know so little and it is such a complicated web of biological processes that it is involved with.

The child who died in Texas was a Mexican toddler who had been airlifted to Texas for treatment. The child acquired the disease while in Mexico.

WHO pandemic level is now at Phase 5

Now wait a second, according to WHO as reported in the minute-by-minute news coverage this is a pandemic -- run in circles, scream and shout. . . Went to the gym and worked out today, nobody seemed concerned and this is San Diego, we have our share on the map.

Houston's popular blogger, SciGuy, wrote:
If so, that's good news for me living on the Gulf Coast (despite repeated flooding recently).

I did buy some N95 masks once I saw heavy chatter on Twitter; 2 masks/box, and bought 2 boxes for <$5. They're mostly for hubby, since I'm currently doing the homemaker thing. I don't regret buying them. They were cheap, and I knew they wouldn't be available much longer. Hopefully we'll never use them, but should we see the worst happen, at least we'll have some protection better than painter or paper masks.

Shreela now has dust masks for other emergencies like smoke or dust from storms.
Are we all prepared for dust and smoke?

"Warm fuzzy nice nice. What good is science if nobody gets hurt?"
- Chrome Dome

Clinical research and experience, notably with the recent SARS epidemic, heavily suggests that N95 masks offer a considerable degree of protection against transmission influenza. The virus typically isn't "free floating" by itself, and it's size is greatly enlarged by the droplet or aerosol particle it's riding in, making the masks more effective in actual use than the size individual virii would suggest. Moreover, they are great for containing the virus when worn by infected persons.

With N95 masks, the face seal is the killer. I don't have much luck with them at all; must be my big melon. (A full-face P100 respirator is my choice for "all-in" situations.)

I wonder, though, given a perfect face seal: AFAIK, flu viruses don't travel solo, but hitchhike in droplets of moisture etc. These are much larger, and the filter medium should catch them. Ditto an infected person -- they should decrease the viral load being released.

For individuals looking for 100% protection, that may not be matter much. But across an infected population, it may (?) tip the balance in favour of a great many individuals.

All in theory, of course.

[EDIT: the two posts above have beat me to the punch.]

Careful, Izzy. I think that this is one of those situations where a little knowledge taken in isolation can lead to an incorrect conclusion. Jeff already covered it, but basically, people sick with the flu don't sling bare, individual virus particles around when they cough or sneeze, so the size of one virus particle is not that important.

Influenza generally is transmitted through "large" droplets when someone coughs or sneezes, and those are generally in the 10 micron range. Large enough to be trapped by the 0.1-0.3 pore size of your average N95 respirator. Smaller, aerosolized particles are also possible, but the predominant transmission method is thought to be through these droplets. And even aerosolized particles will likely be larger than the average pore size of the filter.

Unfortunately, trying to protect yourself involves more than just sticking an N95 on your face. I've said it in the past, but without the knowledge and training to know how to put it on and make sure it fits properly, know what situations to use it in, know when it's safe to take off, know how to take it off so you don't accidentally infect yourself, know when to change a mask, etc., having an N95 could just provide a false sense of security. A person might put themselves at greater risk, like being among a crowd of people, because they think the mask protects them when in fact, it really isn't because, for example, it doesn't fit properly.

There is still little or no good evidence that masks provide any significant protection to the general public (as opposed to trained healthcare workers). For average folks, strategies like hand washing, cough etiquette, avoiding crowds, etc. are going to be more effective overall in helping control any outbreak in your community since they go the heart of disrupting the habits that get us infected. And knowledge is not something that you can run out of, like you can with masks.

Jeff mentioned another important point--masks can help keep sick people from infecting others. In Mexico City, where soldiers are giving various types of masks to people, the logic may be to minimize the risk of infected people from spreading the infection, rather than trying to protect the healthy from getting infected. Or it could be more of a psychological benefit to receive a mask, but to me, I think the comfort of having a mask is outweighed by the feeling of seeing everyone else around you with a mask on.