Obese people may be at greater risk of death or severe complications from the new H1NI virus, according to researchers.
The researchers from U.S. said Friday obese persons who don't have underlying health conditions and are otherwise healthy, still may be at special risk of severe flu complications from the new swine flu virus.
The study, published in advance in the Centers for Disease Control and Prevention's weekly report on death and disease, also suggests doctors can safely double the usual dose of oseltamivir, Roche AG's antiviral drug sold under the Tamiflu brand name.
Doctors cited a recent case of 10 patients at a Michigan hospital: seven of the 10 patients were so ill they had to be put on ventilators. Three died.
Nine of the 10 H1N1 flu victims with serious complications such as multiple organ failure and blood clots in the lungs were obese (body mass index more than 30). Seven were severely obese, including two of the three who died.
"What this suggests is that there can be severe complications associated with this virus infection, especially in severely obese patients," said CDC virus expert Dr. Tim Uyeki.
"And five of these patients had ... evidence of blood clots in the lungs. This has not been previously known to occur in patients with severe influenza virus infections," Dr Uyeki said.
H1N1 is different than seasonal flu in that it spreads in the summer months, attacks young adults and older children, and may affect the body slightly differently. Another type of flu studied, H5N1 avian influenza, rarely attacks people. But with avian flu, patients seem to survive better if they get extra-high doses of Tamiflu for longer than the usual 10-day treatment course, said the researchers.