May 10, 2011
Study: Few hospital workers seropositive for pandemic H1N1 after first wave
After the first wave of the 2009 H1N1 influenza pandemic, only about 5% of healthcare workers (HCWs) in two hospitals in Kobe, Japan, tested positive for antibodies to the virus, according to a report in the Journal of Infection. Researchers used a questionnaire and blood sampling to conduct their study, drawing participation rates of 82% and 84% in the two hospitals. Of 268 HCWs, 14 (5.2%) were seropositive for the pandemic virus. Only one worker reported having had any symptoms (a fever). HCWs who had been exposed to flu patients were more likely to be seropositive than those with no exposure (6.8% vs 3.1%), but the difference was not significant. Among emergency department nurses, those who consistently wore a surgical mask or N-95 respirator were more likely to be seronegative than those who wore the equipment only sometimes or never (6.59 times more likely for masks, 2.28 times for respirators), but this difference, too, was not significant.
May 8 J Infect study
Hong Kong finds H1N1 patterns with GIS tools
A geographic information system (GIS) study of more than 24,000 lab-confirmed 2009 H1N1 cases in Hong Kong found evidence of clusters during the first weeks of the outbreak of the new virus alongside multiple foci that depicted infections brought from abroad. The data, published in the Journal of Infection, were from cases that occurred between May 2009 and Sep 30, 2009. In urban areas, clusters grew rapidly and became confluent, whereas local clusters in the northern part of the region flared up, then eased over a shorter period. They concluded that evaluating the spatio-temporal dynamics of flu spread can help public health officials more effectively plan response activities, tailoring them to community needs.
May 7 J Infect abstract
Study tests prime-boost vaccination strategy for H5N1
Writing in Vaccine, a US-Canadian team of researchers reports favorable results in a test of the prime-boost vaccination strategy for a flu pandemic, which involves giving a population a pre-pandemic subtype-specific vaccine and following up with a vaccine matched to the pandemic strain after its emergence. The study involved 469 adults who, 15 months earlier, had received two doses of an H5N1 vaccine based on a 2005 Indonesia strain, with or without GlaxoSmithKline's AS03 adjuvant. In the new study, the participants received one dose of an H5N1 vaccine based on a Turkish strain of H5N1, with or without the adjuvant. The study did not demonstrate that adjuvanted priming was superior to nonadjuvanted priming, but higher and more enduring antibody titers were seen when both the prime and booster doses were adjuvanted, which could be important for protection against drifted strains. The booster vaccines had acceptable safety profiles. The authors conclude that "priming with a two-dose series of pre-pandemic vaccine and subsequent immunization with a vaccine matched to the pandemic strain is a viable strategy to protect the public in the setting of an H5N1 influenza pandemic."
May 7 Vaccine report