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17 April 2014 12:48 pm ,
Vol. 344 ,
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
- About Us
Where's swine flu? Check the traffic
21 February 2010 4:16 pm
The students poured into Carlos Castillo-Chavez's office soon after swine flu struck Mexico last spring. The graduate students, some from Mexico, a few from Puerto Rico, knew the Arizona State mathematician was an expert in modeling disease spread.
"They were very scared because they had relatives there," said Castillo-Chavez. "They asked, 'Is there something we can do?'"
The cadre of concerned students worked Saturdays and Sundays to model the ensuing outbreaks of H1N1, which peaked three separate times in Mexico. In the model world they created, people were either susceptible or exposed, vaccinated or not.
They found that cases of H1N1 plunged when schools shut their doors, families went on vacation, and people intentionally isolated themselves, Castillo-Chavez reported here Sunday. But they also found an intriguing, smaller effect--the coming and going through Mexico City, the beating hub connecting 20 percent of the population, predicted the weekly variations in flu cases when school closed for the summer.
Delivering vaccines quickly--more than 40 days before the next outbreak--prevented severe outbreaks in the model. That's because even if the vaccine was in short supply, allocating it wisely made the difference between a severe outbreak and a mild one.
How the Mexican government actually responded, according to Castillo-Chavez, wasn't too far from his model's optimal solution.
"Mexico did a superb job given high levels of uncertainty," said Castillo-Chavez. "They took painful and extreme measures right away," he said, like closing down businesses and giving out surgical masks. Not every country might have responded that way--Chinese public health officials were slow to admit in 2003 that SARS had broken out, he said. The World Health Organization and French president Sarkozy praised Mexico's quick response, though some first-responding doctors have said Mexico did lag a bit.
But one shortcoming of his model, and of disease prevention worldwide, is knowing exactly how many people are infected at a given time, as the number of reported cases may be low estimates.
"We can't tell how bad things are. We don't have this extensive network of high quality systems. That would be the most important thing to put in place."