Will pandemic be mild, or kill millions?

By Laura MacInnis - Analysis

GENEVA (Reuters) - Swine flu will carry the name "pandemic" even if the new virus turns out to cause mainly mild symptoms as it sweeps the world, raising questions about how serious the global alert actually is.

Although it has been deadly in the disease epicenter, Mexico, and caused the death of one Mexican infant in the United States, in other countries people infected with swine flu have fared well, with diarrhea the biggest complaint.

The World Health Organization is expected to move quickly to designate a full pandemic -- at level 6 of its 6-point scale -- within days to reflect the continuing spread of swine flu among people who have not been to Mexico, including in Europe.

Margaret Chan, the WHO's director-general, on Wednesday night raised the world flu alert level from 4 to 5 and said: "It is really all of humanity that is under threat during a pandemic."

Echoing other infectious disease experts, and drawing on her experience fighting SARS and bird flu outbreaks as health director of Hong Kong, she said viruses such as the H1N1 swine strain needed to be closely watched in case they worsen.

"We learn from previous pandemics. Pandemic virus is precarious, unpredictable, and will take us by surprise," she told reporters at the WHO's headquarters.

PATIENTS RECOVERING WITHOUT DRUGS

But Chan acknowledged that the disease may well cause more discomfort than death, noting that many patients infected in the United States have recovered on their own and without medicine.

"It is possible that the full clinical spectrum of this disease goes from mild illness to severe disease. We need to continue to monitor the evolution of the situation to get the specific information and data we need to answer this," she said.

"There may be a possibility that the virus will die out and stop, and that would be the best for us. But it can turn the other way."

Several theories are circulating about why swine flu has killed as many as 176 people in Mexico while having mild and more manageable effects elsewhere.

Some experts speculate that the Mexican victims did not receive appropriate medical care or suffered other health complications that made them vulnerable to the flu.

For the time being, the WHO's own guidance to people who suspect they have been infected with swine flu is essentially the same as advice for seasonal flu care.

Its website's "frequently asked questions" about the virus tell people who have a high fever, cough or sore throat to rest and take plenty of fluids, wash hands frequently, and avoid work, school or crowds as much as possible. (www.who.int/csr/disease/swineflu/faq/en/index.html#q11)

MILD OR SEVERE PANDEMIC?