The H1N1 virus first emerged in Mexico earlier this year, setting off panic around the globe. But the initial scare subsided after the virus turned out to be less severe than originally feared. Still, it has spread at an alarming rate, sickening children and young adults more frequently than the typical seasonal flu. And now with the second wave starting to hit, officials still don't agree on how serious it will be. In short, they're racing against time to meet an enemy who remains a rapidly moving target.
So far, the flu, which was upgraded to pandemic status in June because of its rapid rate of transmission, has been less deadly than previous pandemics. As of September 6, there have been more than 277,607 cases of the flu worldwide, with at least 3,205 deaths, since it first appeared in the Spring, according to the World Health Organization.
In the United States during roughly the same period (up to August 30), there have been 9,079 hospitalizations and 593 deaths, according to the Centers for Disease Control and Prevention (CDC). Compare that with the last pandemic in the U.S. that killed 34,000 in 1968.
But doctors fear a possible surge in cases in the fall, if what happened in the Southern Hemisphere is any guide. That region of the world is just coming off its winter, which saw a flare-up in cases that coincided with its traditional flu season. The new H1N1 flu now accounts for 76 percent of influenza viruses circulating globally, according to the WHO.Some of the forecasts have been downright scary. The H1N1 swine flu could infect half the U.S. population this fall and winter, according to the President's Council of Advisors on Science and Technology report. The same report warns 1.8 million people could end up in hospitals and that there could be as many as 90,000 deaths -- more than double the number that occur in an average flu season.
What's more, the presidential council says 60 to 120 million people are expected to show symptoms, mostly mild ones, with up to 300,000 people who could require intensive care. By contrast, the seasonal flu is associated with 30,000 to 40,000 deaths and 200,000 hospitalizations each year.
But not all experts agree with the presidential council's rather grim scenario. For one, the CDC says the numbers are too high. While swine flu spreads easily, it so far hasn't been more deadly than the other seasonal flu strains seen every fall and winter, the CDC said. Some experts actually would prefer to deal with swine flu over the regular seasonal influenza virus, saying it is milder and lasts less time.
Regardless of the differences in severity forecasts, swine flu represents a formidable foe. Among some of the challenges are its fast spread rate and the high infection rate among young adults. Swine flu spreads four times faster than other viruses and 40 percent of the fatalities are young adults in good health, WHO Director General Margaret Chan told France's Le Monde. "This virus travels at an unbelievable, almost unheard of speed," she told the daily
Other challenges? Influenza viruses are unpredictable and tend to mutate, experts add. A combination, say, of the highly transmittable -- but mild -- H1N1 virus with the less easily transmittable -- but deadly -- H5N1 could produce a nightmare virus: one that is highly transmittable and very deadly. To prepare for the worst case, CDC scientists are now working on combining the two in the lab to better understand the potential, reported the WSJ Health Blog. But so far, close genetic tracking of the virus as it circled the globe over the last few months has shown no sign that it's mutating to become more virulent, the CDC said.
The other problem, of course, is a potential shortage of vaccines. On that front, the Obama Administration has gotten into gear, recently appropriating $2.7 billion to buy swine flu drugs and vaccines, on top of the $1.8 billion already allocated in July. The Department of Health and Human Services finally seems to be on track, or ahead of, its revised swine flu vaccinations timeline, with shots potentially available in the first week of October. There had been several earlier delays.
Despite the progress, a vaccine shortage is still expected. Of the 195 million doses ordered, only about 45 million will be available to begin a planned mass vaccination within the next few months. With only a quarter of the ordered doses available in the near future, it doesn't seem there will be enough for the 159 million people in recommended groups to receive the vaccine because of various vulnerabilities.
Among the priority groups are:
- pregnant women,
- people who live with or care for children younger than 6 months of age,
- health care and emergency medical services personnel with direct patient contact,
- children 6 months through 4 years of age, and
- children 5 through 18 years of age who have chronic medical conditions.
The appearance of the flu earlier this year has given vaccine manufacturers the time to prepare the vaccine and test it ahead of time. There are now five companies registered to manufacture the vaccine. All have received large orders from the U.S., with production and testing well under way. Sanofi Pasteur of Sanofi Aventis (SNY) landed a $252-million order, Novartis (NVS) got $978 million, GlaxoSmithKline (GSK) received $250 million, MedImmune of AstraZeneca (AZN) bagged $151 million and CSL Therapeutics brought in $180 million.
Vaccine makers delivered some good news last week when clinical trials showed that one dose of the new H1N1 swine flu vaccine is enough to protects adults. CSL's three-week trials in Australia -- and similar studies in the U.S. -- showed adults who received only a single dose were protected within 8 to 10 days. The availability of the vaccine earlier and its effectiveness could save lives of high-risk groups, experts said.
But vaccines alone won't do enough to stem the spread of the disease. The CDC recommends five main steps the people can take to help prevent the spread of the flu and to protect themselves: Cough into your hand or sleeve, wash your hands regularly, avoid hand contact with your face, and avoid contact with sick people. Finally, the CDC recommends staying at home if you experience symptoms, which are similar to regular flu symptoms, often accompanied by diarrhea and vomiting.
For now, at least, it certainly doesn't seem like swine flu will prove to be as ferocious as previous pandemics. Let's hope Survivors, I am Legend and The Stand remain works of fiction. But if you're hedging your bets, there's always Flu.gov and the "Outbreaks Near Me" iPhone App to keep you on top of any developments.
[Update: On Friday, the WHO said that the annual production of swine flu vaccines is expected to fall well short of the 4.9 billion doses that it had earlier forecast. However, since one dose now seems enough, supply fears have eased.]