GMS-CDC

When the coughing stops is probably a better sign of when a swine flu patient is no longer contagious, experts said after seeing new research that suggests the virus can still spread many days after a fever goes away. The Centers for Disease Control and Prevention (CDC) has been telling people to stay home from work and school and avoid contact with others until a day after their fever breaks. The new research suggests they may need to be careful for longer – especially at home where the risk of spreading the germ is highest.

Three reports suggest this is so. De Serres and other researchers in Canada took nose and throat swabs from 43 patients with lab-confirmed flu and dozens of other sick family members. On the eighth day after symptoms 1st 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 C. 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 5 days after symptoms began, and 40 percent 7 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 2 days after symptoms first appeared.
(ProMED 9/15/09)


Referrer: Apec-ein