Researchers studied closely matched isolates of pandemic H1N1 in ferrets and found the oseltamivir (Tamiflu)-resistant strain to not transmit efficiently via droplets but to transmit well via direct contact. The oseltamivir-sensitive strain transmitted well via both routes. Although both strains caused a similar disease course, they found signs of lower viral fitness in the resistant strain. The authors said drug-resistant strains must continue to be closely monitored. [Jul 29 PLoS Pathog study]

An Australian study comparing attitudes during the pandemic with those 2 years prior showed increased hand washing but a drop in willingness to comply with certain prevention efforts. About 47% reported increased hand washing, and 28% reported increased covering of coughs and sneezes. The percent willing to be quarantined stayed about the same, but willingness to avoid public events and social gatherings for a month and to wear a mask in public dropped over the 2 years. [Aug Emerg Infect Dis study]

Mexican researchers compared more than 200,000 cases of flu-like severe acute respiratory illness during the pandemic with 60 patients with Down syndrome who reported the same flu-like symptoms in the same period. They found that those with Down syndrome were 16 times more likely to be hospitalized, eight times more likely to require intubation, and 335 times more likely to die from the disease. They recommend vaccination and early antiviral treatment in this group. [Aug Emerg Infect Dis study]

Though many are calling for the World Health Organization (WHO) to incorporate severity into its pandemic alert phases, a renowned virologist is saying no. Malik Peiris of the University of Hong Kong said there was no doubt novel H1N1 was a pandemic, well before the WHO declaration. "We really don't have good assessments of severity," he told The Hindu. "So it would completely paralyze international public health policy, I think, if severity is linked to the definition of a pandemic." [Jul 29 The Hindu story]

A seroprevalence study of 7,962 people aged 1 to 60 years found that, from August to October 2009, people had these rates of antibodies to pandemic flu: Costa Rica (26.4%), the United States (22.5%), Switzerland (16.9%), Germany (12.6%), Belgium (10.1%), and Japan (5.9%). The authors write, "The low proportion of seropositive children in Europe and Japan suggests that little local viral transmission had occurred." They say the data show that public health steps in late 2009 were justified. [Jul 29 Eurosurveillance study]

Today in Morbidity and Mortality Weekly Report, officials from Skokie, Ill.'s health department detail how they administered 40,000 doses using a five-phase H1N1 vaccination campaign. Highlights included school and day care clinics that reached a large number of staff and caregivers as well as children, targeting emergency medical services personnel, shifting unused vaccine from the school clinics to medical clinics, employing mass-vaccination clinics, and reaching out to the homebound. [Jul 30 MMWR report]

A study of 475 severe, 73 critical, and 69 fatal pandemic H1N1 cases in Beijing last year showed that heart disease, diabetes, and allergies increased the risk of serious disease, while obesity and pregnancy did not. Also, those aged 6 to 17 years had a lower risk of serious illness. The city had a case-fatality rate of 0.6%, and serious cases made up 5.7% of all H1N1 cases. About half the patients had no underlying condition (58% of severe, 53% of critical, and 41% of fatal cases). [Jul 27 J Infect abstract]

Japanese public health staff visited 124 homes of people infected with pandemic flu last year, educating household contacts about flu-avoidance steps and providing 88% of contacts with antiviral drugs (postexposure prophylaxis, or PEP). The secondary attack rate (SAR) in the households visited was 0.6% in contacts given PEP (2 of 331, including an antiviral-resistant case), compared with 26.1% in those with no PEP (12 of 46). The researchers estimated the protective efficacy of PEP to be 98%. [Jul 27 J Infect abstract]

South Korean researchers who surveyed 942 college students last December found that 30% said they had increased their frequency of hand washing over the previous year. Female students, students who perceived hand washing to be effective, and those who perceived H1N1 illness to be more severe were more likely to wash hands frequently. The authors say their results suggest that public education campaigns are effective at changing behavior [Jul 28 BMC Infect Dis abstract]

India reported 548 pandemic flu cases and 38 deaths for the week ending Jul 25, up significantly from 332 cases and 21 deaths the week before, according to the country's Press Information Bureau (PIB) today. The southern states of Maharashtra (19), Kerala (8), and Andhra Pradesh (5) reported the most deaths. All of the newly infected patients contracted the disease within the country. [Jul 27 PIB release]

Gambia's Ministry of Health and Social Welfare announced yesterday that it has started its vaccination campaign against pandemic H1N1 flu in collaboration with the World Health Organization, according to the Daily Observer today. The program will last all week and aims to reach 170,000 people, with priority given to health workers, pregnant women, children, and those with underlying disease. [Jul 27 Daily Observer story]

The US Centers for Disease Control and Prevention (CDC) released a question-and-answer document explaining what providers should do with expired H1N1 vaccine. Because the federal government issued the vaccine, the process to return it differs from that for both seasonal flu vaccine and the Vaccine for Children program. The recovery program applies to unopened vaccine that expired Jun 30 (from CSL, Novartis, and MedImmune) but not to Sanofi's multidose vials, which expire in 2011. [Jul 23 CDC Q&A]

Of 237 cases of pandemic flu in those receiving organ transplants in 26 US, Canadian, and Dutch centers, 167 (71%) were hospitalized because of their infection. Of 230 patients for whom data were available, 73 (32%) had pneumonia, 37 (16%) were admitted to intensive care, and 10 (4%) died. The authors conclude, "Influenza A H1N1 caused substantial morbidity in recipients of solid-organ transplants during the 2009-10 pandemic" and that early antiviral therapy provided clinical benefit. [August Lancet Infect Dis abstract]

Having diabetes triples a person's risk of being hospitalized for pandemic H1N1, according to a new study. Of 162 patients with lab-confirmed novel H1N1, 22 (14%) had diabetes (9 with type 1 and 13 with type 2). This was three times the 7.1 cases expected, based on population demographics. Also, the diabetic H1N1 patients had quadruple the risk of requiring intensive care compared with other H1N1 patients. The authors conclude that their results corroborate other findings in those with diabetes. [July Diabetes Care abstract]

In a study on mice and ferrets, researchers found that the oseltamivir (Tamiflu)-resistant pandemic flu strain was just as virulent as the oseltamivir-susceptible strain. The two strains differed only by a single change (H274Y mutation) in the neuraminidase protein. The authors state that "the H274Y pH1N1 mutant strain has the potential to disseminate in the population and to eventually replace the susceptible strain," a phenomenon that has already occurred in seasonal flu. [Jul 22 PLoS Pathog study]

Pockets of West Africa, Central America, the Caribbean, and South and Southeast Asia continue to have the most active pandemic flu activity, while overall global flu activity remains low, the World Health Organization (WHO) said in its weekly update today. Australia and New Zealand have seen recent increases in respiratory disease, mostly pandemic flu. Influenza B and H3N2 are dominating South Africa's flu season. The areas with highest H1N1 activity in Asia are India, Cambodia, and Singapore. [Jul 23 WHO update]

Two telephone surveys in May and June 2009 enabled New York City health officials to quickly assess the prevalence and severity of pandemic flu, according to a study published in PLoS One. The polls indicated that the prevalence of flu-like illness in a 50-day period was 15.8%, and estimated case-fatality rates for H1N1 ranged from 0.054 to 0.086 per 1,000. The surveys indicated that the risk of severe illness was similar to that with seasonal flu, which influenced the city's pandemic response. [Jul 21 PLoS One report]

Health ministers from the Association of Southeast Asian Nations (ASEAN) today during a retreat in Singapore called on the World Health Organization (WHO) to review its current pandemic alert level, Xinhua, China's state news agency, reported. They said flu activity has reached the post-pandemic phase and that future assessments should account for severity or virulence. The request comes a day after the WHO announced it was waiting on clearer signals from the Southern Hemisphere and other areas. [Jul 22 Xinhua story]

Google Flu Trend (GFT) monitoring during the H1N1 pandemic in Europe correlated well with peaks in sentinel physician network surveillance in several countries, according to a report today. The authors suggested that GFT could be a useful adjunct to other systems because it provides a more rapid estimate that is most relevant in countries with large numbers of Internet users that perform regular Web searches. An earlier comparison of GFT and US flu data showed similar results. [Jul 22 Eurosurveillance report]

Researchers studying influenza viruses of the N1 neuraminidase subtype (eg, H1N1, H5N1) in birds and pigs found resistance to the common antiviral drug oseltamivir (Tamiflu) to be low. For example, of 91 isolates collected from ducks, shorebirds, and gulls, 7 (7.7%) had reduced susceptibility to the drug but were susceptible to related antivirals zanamivir (Relenza) and peramivir. N1 strains from swine, birds, and humans formed the novel H1N1 flu that caused the current pandemic. [Jul 21 J Virol abstract]