Swine Flu Tops List of 2009 Health Issues

In early 2009, Mexico was the epicenter of a mysterious outbreak. A severe respiratory illness was affecting young people, contrary to seasonal viruses that often attack the elderly.

Health officials in Mexico and the United States were puzzled by a virus that combined elements of swine猪流感, avian 鸟流感and human influenza流行性感冒.

It was nicknamed Swine Flu, although a few months later public health experts began calling it by its proper name: H1N1.

Because Mexico is a popular tourist destination, Swine Flu quickly spread beyond North America to parts of Europe and Asia.

Dr. Margaret Chan, Director General of the World Health Organization (WHO), began a series of daily briefings每天记录to track H1N1 as it spread around the globe.

On June 11th, she announced the WHO was raising it to a pandemic.

"The virus is spreading under a close and careful watch," she said. "No previous pandemic has been detected so early or watched so closely, in real-time, right at the very beginning."

The WHO authorized drug manufacturers to begin testing possible vaccines, and the first human trials began a month later.

By October, the first batches批次 were distributed to health care workers, pregnant women, young people and those with underlying medical conditions.

Dr. Anne Schuchat is director of the U.S. Centers for Disease Control and Prevention.

"As the supply increases, we do think that access and convenience and ease of getting vaccinated免疫接种 will improve," she said.

By late December, WHO reported that more than 10,000 people had died from H1N1. Most of those deaths occurred in North America.

WHO says many countries have stopped counting the people with milder cases.

The virus appeared to be leveling off 趋于平缓in North America and Europe by year's end. But some experts say it could come back in a third wave early next year.