Jul 7, 2009 (CIDRAP News) – The World Health Organization (WHO) said today it will soon advise most countries to ease the volume of testing for novel H1N1 influenza and said testing related to recent oseltamivir-resistant cases has so far turned up no additional cases.
Keiji Fukuda, MD, the WHO's assistant director-general for health security, in an update for journalists today, said the pandemic situation is evolving rapidly across the globe, with changes occurring continuously even within individual countries.
In the next few days the WHO will release its new surveillance recommendations, advising countries that have already confirmed cases to cut back on testing all suspected cases and move toward larger surveillance indicators such as influenza-like illnesses or pneumonia hospitalizations.
"This will also ease the burden on labs," he said, adding that countries will still be urged to continue testing when unusual situations surface, such as severe cases, clusters, and symptoms that haven't previously been reported.
However, Fukuda said the WHO will still advise countries that haven't yet identified any novel H1N1 cases to continue testing people who have suspected infections.
In other developments, he said the WHO's Strategic Advisory Group of Experts (SAGE) on immunization met today in Geneva and is expected to forward its report to Dr. Margaret Chan, the WHO's director-general, over the next several days. According to a notice on the group's Web site, the agenda includes updates on novel H1N1 vaccine production, safety, regulatory issues, and discussion on key topics such as how much vaccine will be needed and which groups should be immunized first.
Regarding the three recently identified oseltamivir (Tamiflu)-resistant novel H1N1 strains in Denmark, Japan, and Hong Kong, Fukuda said that so far there is no evidence of widespread movement of the resistant strains, that testing of the patients' close contacts has so far identified no other infections with the strains, and that experts see no evidence of reassortment with the seasonal H1N1 strain.
Influenza experts expect to see some spontaneous mutations in circulating novel H1N1 flu strains, he said.
Though the patient in Hong Kong had not taken the antiviral drug oseltamivir, raising concerns that she may have contracted the infection from someone else taking the medication, the virus that caused her illness had the same mutation as the resistant viruses identified in Denmark and Japan, he said.
"An important point is to continually monitor to make sure we're not seeing widespread movement [of the antiviral-resistant strain]," Fukuda said. "And the single most important point is that we're not recommending any clinical changes."
Varied activity in southern hemisphere
Pandemic flu activity in the northern hemisphere is high right now, but it's hard to predict how the virus will spread over the rest of the summer, Fukuda told reporters. In the southern hemisphere, influenza activity varies by country, with heavy activity reported in Australia and South America, but with the first cases detected in 12 African countries only over the past few weeks.
The dominance of the novel flu also seems to vary by country, he said. For example, Chile is reporting that 99% of circulating strains are the pandemic virus, though Australia is seeing a mixed picture of both novel H1N1 and seasonal H3N2. In contrast, the seasonal H1N1 strain is more predominant in South Africa.
"Overall for the southern hemisphere, it's still early in their season," he said. "In another month we'll have a much clearer picture of how pandemic flu is spreading and if it's crowding out seasonal flu."
Fukuda also addressed a reporter's question about new nomenclature for the novel flu virus that has been adopted by the WHO, the United Nations Food and Agriculture Organization (FAO), and World Organization for Animal Health (OIE). He confirmed that experts from the groups have decided to call the virus "pandemic (H1N1) 2009." He said the groups wanted to adopt a term that is scientifically accurate, but avoids stigmatizing a geographic location or animal population.
Jul 7 WHO SAGE agenda on immunization