May 26, the US Centers for Disease Control and Prevention suggested that the swine flu outbreak in the country could have crested. But Donald Olson, an epidemiologist based in New York City who heads the influenza surveillance project at the International Society for Disease Surveillance (ISDS), disagrees. "If New York City, Boston and Seattle are indicators of what is to come for the rest of the country, then we still have not seen anything," says Olson.
CDC based its optimistic assessment on " like illness "(ILI) reported in ambulatory care clinics in their surveillance system and found a decrease in seven of the nine regions of the country (the two exceptions include New York and Boston). But ISDS collects its own data from a dozen sites across the country, and, as Olson explains, is able to "drill down" and analyze more subtle measures such as fever and severe pneumonia. Their analysis, he said, indicates that the first weeks of the outbreak of swine flu have led many people who have had respiratory diseases and diarrhea "worried sick" to get medical care. "Normally, these people would have stayed home sick," Olson said.
As the fear of swine flu has decreased Olson suspect that many of these people went to the doctor, leading to decreases in reports of ILI are not specific indicators of drops in the spread of the new H1N1 virus that causes swine flu.
Although CDC also noted increases in Boston and New York City, Olson said his most carefully analyzed the data showed "massive increases" that look "soft" in the CDC regional data. CDC also shows ILI Seattle off at week 20, which is the opposite of what is ISDS. Unfortunately, Olson said, no one has systematically collected data on the real presence of the new H1N1 virus because it overtax testing laboratories. "We are dealing with so much uncertainty, and we imperfect measures," said Olson. "But we need to know what they have weaknesses."
Olson said it is possible that the epidemic exploded, quickly infected the susceptible population, and will now disappear, but he doubts that, given that new York City has seen the peak of the disease, gout, then peak again. "If what new York City has seen in the last 10 days is any indication, we'll be seeing anywhere else, "said Olson
Image credit :. ISDS
See larger version of the graph
0 Komentar