The outbreak of pandemic H1N1 influenza appears to be waning in the United States and Canada and may be nearing a peak in the rest of the world, but it is impossible to predict what will happen with influenza viruses, the World Health Organization said today. "It's too early to say whether activity is peaking in the northern hemisphere and at this point it is also not possible to predict what we are going to be seeing in the springtime," Dr. Keiji Fukuda, special advisor on pandemic influenza to the WHO's director-general, said at a telephone news conference in Geneva. "We continue to see that most activity is in the Northern Hemisphere with lower levels in the Southern Hemisphere... What you see in one country is not necessarily what you are seeing in another country."
Fukuda acknowledged that the virus has proved less lethal than authorities originally feared. "It is possible there could be unexpected events which occur as we go through" the pandemic, he said. But "it is quite possible to have a pandemic on the milder side and if we are experiencing that, and if the number of serious cases is kept down ... this is something for which we should all be thankful."
Fukuda said that more than 150 million doses of swine flu vaccine have now been distributed in about 40 countries. The United States, with at least 70 million doses, represents nearly half that total.
He also said that, so far, researchers have identified 96 patients with strains of the swine flu virus that are resistant to the most commonly used antiviral agent, Tamiflu, known generically as oseltamivir. That includes four patients hospitalized at Duke University Medical Center in North Carolina, three of whom died. Duke officials said earlier this week that they have found no other cases of resistant virus, despite heavy screening, and Fukuda said that seems to be the case in other places where the virus has been identified. "We do not see widespread resistance to oseltamivir anywhere," he said. In a posting on its website Wednesday, the WHO noted that many of the cases of resistance to Tamiflu occurred in patients with severely compromised immune systems. The agency recommended that, if resistance is detected, the patients be switched to Relenza, an intranasal antiviral agent. Failing that, they can also be treated with the intravenous antiviral drug peramivir.
New data from college campuses support the idea that swine flu may have passed its peak in the United States. For the week ending Nov. 27, there were only 1,076 new cases of influenza-like illnesses, generally presumed to be swine flu, among the nearly 3 million students covered in the survey, a 69% drop from the previous week. The data, compiled by the American College Health Assn., marked the third consecutive week of declines on college campuses. There were four hospitalizations during the week and one death, the second reported on the 220 college campuses that report to ACHA. That week was a holiday week during which many students went home for several days, however, and that may have biased the results.
About 84% of the campuses report having some swine flu vaccine on hand, but so far only 5% of the campus population has been immunized.
-- Thomas H. Maugh II