THURSDAY, Jan. 20 (HealthDay News) -- This winter, influenza
seems to be behaving very differently depending on what side of the
Atlantic you're on.
As of last week, for example, H1N1 ("swine") flu still
predominated in Britain, where 112 people have died, hospitals are
filling up with very ill flu patients, and some doctors report
running out of vaccine, according to the
BBC. Experts are concerned that the virus -- known as 2009 H1N1 -- could create a similar situation in mainland Europe.
However, in the United States, clinicians are only now starting
to see cases of the flu -- mostly of the traditional, H3N2 variety
-- and the atmosphere is much more calm. Vaccine is plentiful and
much of it is going unused.
Still, with modern air travel allowing viruses to spread easily
around the globe, could the British flu experience travel to
That question remains unanswered. According to experts, it's
still relatively early in the flu season and anything could
In Rochester, N.Y., "we're getting a mix of a little bit of H1N1
but not much. We're seeing more of H3N2 and some influenza B, so
all three players are in the pot," said Dr. Edward Walsh, an
infectious diseases expert and professor of medicine at the
University of Rochester Medical Center. "As to which one is going
to be dominant, we're waiting and seeing. I don't think we can
predict that yet."
Walsh's reports mirror those of the U.S. Center for Disease
Control and Prevention, which says -- for the week ending Jan. 8,
2011 -- about 8 percent of samples tested were 2009 H1N1 and 31.5
percent the H3N2 variety.
Still, H3N2's dominance "could change very quickly," Walsh
One theory as to why H1N1 hasn't made a strong showing in the
United States this year is that many Americans gained immunity last
"So much of the U.S. population was vaccinated against H1N1 last year and so much immunity developed as the thing spread like wildfire, that's the reason the predominate strain is H3N2 -- it's all about immunity," said Dr. Marc Siegel, an associate professor of medicine at New York University in New York City.
But a comeback for the strain -- which is typically more serious
for younger patients -- isn't out of the question.
H1N1 "appeared at a distinctly odd time in its initial debut in
April/May of 2009 [flu season usually ends in March or even a
little earlier] so it's obviously got an unpredictable course as to
when it's going to actually attack a population," noted Dr. Len
Horovitz, a pulmonary specialist at Lenox Hill Hospital in New York
"What will happen in any individual country or area, we just don't know. It's impossible to estimate," added Dr. John Carpenter, professor of internal medicine at Texas A&M Health Science Center College of Medicine and division director of infectious diseases at Scott & White in Temple. "We just don't know if it will come over here. If somebody hops on a plane with it and comes over here..."
But, he added, "if it jumps to Europe, there's a better chance
it will jump here."
And experts aren't ruling out the possibility that there could
be regional variations in the United States, with different strains
leading in different areas.
"You don't always get the exact same thing in every country or even within every region," Walsh said.
In the meantime, people should not underestimate the potentially
deadly nature of H3N2, which tends to hit the elderly the hardest.
Siegel expects to see more elderly patients than last year -- and
more deaths. H3N2 tends to cause more pneumonia and other
complications than other forms of flu, he said.
"Last year, there were 10,000 deaths compared to the normal 34,000 [from flu]," he said. If H3N2 continues to predominate, "the age distribution of deaths this year will be back to the elderly," Seigel said.
Whatever strain ends up as the predominant one, this year's
vaccine -- which contains H1N1, H3N2 and Influenza B -- should help
"It's not definitive yet but it's reasonable to think it will be a good match," said Walsh.
According to the
Associated Press, this has been a banner season for flu vaccine production in the United States, with 160 million doses already made. So while Britain is running short on vaccinations, the U.S. supply should hold up to any spikes in demand.
The CDC recommends that all people aged 6 months and over get
the seasonal flu shot, with priority given to pregnant women, young
children, the elderly and certain other groups.
There's more on the seasonal flu vaccine at the
U.S. Centers for Disease Control and