World

Wuhan virus: Experts say outbreak will last months

WASHINGTON: The deadly new coronavirus outbreak in China will afflict a minimum of tens of thousands of people and last at least several months, researchers estimate, based on the first available data.

"The best case scenario, you would have something... where we go through the spring into the summer, and then it dies down," said professor David Fisman at the University of Toronto who wrote an analysis of the virus for the International Society for Infectious Diseases.

Northeastern University professor Alessandro Vespignani said: "It's not something that's going to end next week or next month." He is part of a group of researchers that manages an online dashboard about the outbreak.

Epidemiologists have only piecemeal information on the new virus, which appeared last month. They use mathematical models to estimate the actual number of cases, as of the current date, and make comparisons with past outbreaks, though many of their hypotheses remain uncertain.

Until last weekend, researchers thought infected people were not contagious until they began exhibiting symptoms, such as fever, respiratory problems and pneumonia.

But Chinese authorities said on Sunday that they had established the opposite.

US health authorities said on Monday that they had not seen evidence that asymptomatic patients can infect other people. If they can, it would definitely change the outbreak's dynamics.

The first estimates for the length of the incubation period - about two weeks - are recent.

In recent days, multiple experts have calculated an important parameter for any outbreak - the basic reproduction number, or "R0".

It represents the number of people contaminated by an infected person. Estimates range from 1.4 to 3.8, according to Prof Fisman, figures that are considered moderate.

That is only an average. Some patients may infect many people, while others infect only a few.

"On its own, it isn't a reason to panic," said researcher Maimuna Majumde at Harvard University and Boston Children's Hospital.

She said the rate is 1.3 for seasonal flu (which has millions of cases per year) and between two and five for severe acute respiratory syndrome (Sars). In comparison, the rate for measles ranges from 12 to 18. - AFP

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