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Biosecurity News in Brief
Survey Finds H5N1 Knowledge Low in Afghanistan; Novavax Pandemic Vaccine Promising in Clinical TrialBy Nidhi Bouri, September 8, 2008 The U.S. Centers for Disease Control and Prevention (CDC) has just released the results of a survey conducted to assess factors that affect the knowledge, attitudes, and practices (KAPs) regarding H5N1 in Afghanistan. Conducted in 2 H5N1 affected provinces and 3 unaffected provinces, the survey found that increased knowledge about reducing exposure to H5N1 was associated with elevated socioeconomic status and residing in an affected province, and not with owning backyard poultry.1 Although there have been no reports of human-to-human transmission of H5N1 in Afghanistan, reports of such transmission in neighboring Pakistan highlight the importance of reducing exposure and increasing reporting through a greater knowledge of the disease. Between February and April 2007, 4 of 34 Afghan provinces confirmed H5N1 in poultry; 20 of 22 outbreak sites in the 4 affected provinces involved backyard poultry. The interventions that were implemented in response included: 1) cull all poultry within a 3 kilometer radius; 2) restrict the mobility and importation of poultry; and 3) implement influenza-like illness surveillance and information, education, and communication (IEC) campaigns within the affected provinces.1 IEC campaigns were intended to prevent the spread of H5N1 in poultry, minimize human exposure to the disease, and promote increased reporting of cases. The authors found that overall knowledge of H5N1 was low in the Afghan provinces that were surveyed. Additionally, KAP scores were highest among populations exposed to IEC campaigns which did not target the provinces’ poorer populations.1 Therefore, lower socioeconomic groups have a considerably higher exposure risk due to the lack of IEC campaigns targeting these populations and the increased likeliness of poultry ownership in those populations.1 In related news, on August 26, Novavax, Inc. announced positive results from the second stage of the Phase I/IIa human clinical trial of its pandemic influenza virus-like particle (VLP) vaccine candidate. The VLP candidate is directed against the H5N1 A/Indonesia/05/2005 avian influenza strain, and “the vaccine, which does not contain an adjuvant, induced robust neutralizing antibody responses.”2 Indonesia documented 135 human cases of H5N1 since 2005, 81% of which were fatal. In the clinical trial, “the vaccine demonstrated strong neutralizing antibody titers across all three doses tested, exhibiting increasing antibody titers with the escalation of the dose.”2 Study participants received 2 injections of 15 micrograms (mcg), 45 mcg, 90 mcg or placebo. Novavax reported that 72% of individuals receiving the 15 mcg dose “had a neutralizing antibody titer of 1:20 or greater (four-fold rise from baseline)” against the H5N1 A/Indonesia strain. This was also true for 73% of individuals receiving the 45 mcg dose and 94% receiving the 90 mcg dose. Novavax also reported that “all subjects tested negative for neutralizing antibodies to the H5N1 A/Indonesia strain before vaccination and no responses were observed among individuals who received a placebo.”2 The trial is still pending complete safety follow-up; however, the Data and Safety Monitoring Board fully supports the continuation of the study up to the 90 mcg dose, as there are no reports of serious reactions. VLPs mimic the size and shape of the virus but are not capable of replication as they lack genetic material. They are able to induce a strong immune response since “they resemble actual infectious particles presenting proteins in the same conformation as on the wild-type virus.”2 Novavax’s influenza VLPs are produced in insect cell culture, which yields 7 to 10 times higher than egg-based or mammalian cell culture manufacturing. Novavax can manufacture a vaccine within 10 to 12 weeks of identifying a pandemic strain, as the technology does not require a live influenza virus, which is approximately half the time duration necessary for manufacturing egg-based vaccines.2 The data from this trial also indicates positive support for a vaccine candidate against seasonal influenza. References
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