Swine flu continues to spread long after fever stops
patients with lab-confirmed flu and dozens of other sick family members. On the eighth day after symptoms first appeared, 19 to 75 percent showed signs of virus remaining in their noses, depending on the type of test used. “This proportion appears to be very big, and it is,” but it’s not clear how much virus is needed to actually spread flu, so the lower number is more reliable, he said.
Dr. David Lye reported on 70 patients treated at Tan Tock Seng Hospital in Singapore. Using a very sensitive test to detect virus in the nose or throat, he found that 80 percent had it five days after symptoms began, and 40 percent seven days after. Some still harbored virus as long as 16 days later. How soon they started on antiviral medicines such as Tamiflu made a difference in how much virus was found, but not whether virus was present at all.
A third report came from Dr. Guillermo Ruiz-Palacios of the National Institutes of Medical Science and Nutrition in Mexico, where the first cases of swine flu were detected.
Infected people “shed the virus for a very, very long time,” often for more than a week after the start of symptoms, he told the conference. This was especially true of obese people, and patients who started on medicines longer than two days after symptoms first appeared.
The new reports suggest a longer contagious period for swine flu, but how long is not clear, Cox said. Even with it in your nose, “you might not be shedding enough virus to infect other people,” she said.
That is why signs like coughing may matter more, De Serres said. “Contagiousness varies, not only with the presence of the virus, but the other symptoms that would make you transmit,” he said.
Swine flu symptoms can include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills, and fatigue, and sometimes diarrhea and vomiting. Young children may be cranky, less playful or not eat as much as normal, the CDC advises.
The agency’s advice to stay home for a day after fever breaks does not apply to health care settings. There, confinement for seven days from the start of symptoms — or until they go away, whichever is longer — is still advised.
People who have had swine flu should cover their mouths when they cough or sneeze and wash their hands a lot once they do return to work and school, the CDC says.
More information:
— Swine flu info: http://www.flu.gov
— CDC advice: http://www.cdc.gov/h1n1flu/guidance/exclusion.htm and http://www.cdc.gov/h1n1flu/qa.htm
— Medical conference: http://www.icaac.org
