It seems clear to me that this new form of flu is spreading rapidly; it will achieve pandemic status quickly. That is not the question. The questions is whether it will be a deadly pandemic. We don't know yet what mortality rates will look like. Swine flu responds to oseltamivir/Tamiflu (at the moment) and zanamivir/Relenza. In the US, it's been a reasonably mild and treatable form of the flu. In Mexico it's been much worse. Just how bad things get depends on how this influenza looks everywhere else.
White Coat Underground may have the best summation:
The flu isn't magic. It's a virus we see every winter. It passes through respiratory droplets, so if it hits hard, masks and frequent hand washing will go a long way. Drugs exist to treat these infections, and the U.S. has an additional emergency stockpile...Unfortunately, the only way to really know how well (or badly) we've prepared is to get hit with a pandemic.
This is the question that has health officials from Geneva to Washington puzzled. In Mexico, swine flu has caused severe respiratory disease in a number of patients - and even more worryingly, has killed the sort of young and healthy people who can normally shrug off the flu. (Fueling such concerns is the fact that similar age groups died in unusually high numbers during the 1918 pandemic.) Yet the cases in the U.S. have all been mild and likely wouldn't have even garnered much attention if doctors hadn't begun actively looking for swine flu in recent days.
Some of the difference may be due to the fact that Mexico has apparently been grappling with swine flu for weeks longer than the U.S. As doctors across the U.S. begin checking patients with respiratory symptoms for swine flu, I'd expect to see more severe cases in the U.S. as well - and as better epidemiological work is done in Mexico, we'll probably hear about more mild cases there too. Right now, however, the true severity of the H1N1 swine flu virus is still an open question, whose answer could change over time. The 1918 Spanish flu pandemic began with a fairly mild wave of infections in the spring, but the virus returned a few months later in a far more virulent form. That could happen with the current swine flu as well. "It's quite possible for this virus to evolve," said Fukuda. "When viruses evolve, clearly they can become more dangerous to people."
Now then, as to whether or not we'e actually prepared.
In some ways, the world is better prepared for a flu pandemic today than it has ever been. Thanks to concerns over H5N1 avian flu, the WHO, the U.S. and countries around the world have stockpiled millions of doses of antivirals that can help fight swine flu as well as other strains of influenza. The U.S. has a detailed pandemic preparation plan that was drafted under former President George W. Bush. Many other countries have similar plans. SARS and bird flu have given international health officials useful practice runs for dealing with a real pandemic. We can identify new viruses faster than ever before, and we have life-saving technologies - like artificial respirators and antivirals - that weren't available back in 1918.
At the same time, the very nature of globalization puts us at greater risk. International air travel means that infections can spread very quickly. And while the WHO can prepare a new swine flu vaccine strain in fairly short order, we still use a laborious, decades-old process to manufacture vaccines, meaning it would take months before the pharmaceutical industry could produce its full capacity of doses - and even then, there wouldn't be enough for everyone on the planet. The U.S. could be particularly vulnerable; only one plant, in Stillwater, Penn., makes flu vaccine in America.
The greatest risk from a pandemic might not turn out to be from the swine flu virus itself - especially if it ends up being relatively mild - but what people call "collateral damage" if governments respond to the emergency by instituting border controls and disrupting world trade. Not only would the global recession worsen, but we depend on international trade now for countless necessities, from generic medicines to surgical gloves. The just-in-time production systems embraced by companies like Wal-Mart - where inventories are kept as low as possible to cut waste and boost profit - mean that we don't have stockpiles of most things. Supply chains for food, medicines and even the coal that generates half our electricity are easily disruptable, with potentially catastrophic results.
The truth is that every outbreak is unpredictable, and there's a lot we don't know yet about the new swine flu. There hasn't been a flu pandemic for more than a generation, and there hasn't been a truly virulent pandemic since long before the arrival of mass air transit. We're in terra incognito here. Panic would be counterproductive - especially if it results in knee-jerk reactions like closing international borders, which would only complicate the public-health response.