A lot are yet to be known about A/H1N1 flu, which spread quickly worldwide, particularly in the United States, and the battle against the virus could prove to be a marathon.
This week has seen the rapid spread of the flu in the United States, as 43 of its 50 states have registered 1,639 confirmed cases, including two deaths, by Friday, making it overtake Mexico as the country having the most confirmed cases.
People still have much to know about the new strain -- a strange mixture of human, avian and swine flu viruses.
Many young and middle-aged people thought to be fit and healthy died of the disease, as its origin is yet to know.
More studies are needed to be done on the A/H1N1 flu, said Mark Dworkin, an associate professor in the University of Illinois at Chicago.
"Perhaps we will learn the answer to these questions after studies are done," Dworkin said.
Influenza virus can mutate. Previous pandemics have shown that new virus could be less ferocious in the early stage before picking up forces and striking again unexpectedly.
That has been the case of the 1918-1919 flu pandemic, which also began in the spring and was initially mild, but a much more lethal version hit six months later before eventually taking 50 million lives worldwide.
Vaccination is the best way to tackle such an epidemic. However, there is a long way to go to produce an effective vaccine against A/H1N1 flu.
"We have already started the multi-step process to develop the vaccine," said Anthony Fauci, head of the National Institute of Allergy and Infections Diseases of the U.S. National Institute of Health (NIH).
However, he cautioned that scientists were "only in the earliest stages" of understanding how the H1N1 virus emerged and what impact it may have.
A vaccine won't be expected until this fall, said Anne Schuchat, acting deputy director for science and program at the Centers for Disease Control and Prevention (CDC).
Just as CDC acting director Richard Besser has put it, "This is a marathon, not a sprint."
(Xinhua News Agency May 9, 2009)
