Jun 8, 2011
Study finds flu, not vaccine, raises GBS risk
Influenza is a likely risk factor for Guillain-Barre syndrome (GBS), while flu vaccine is not, according to an American Journal of Epidemiology study. Researchers identified 145 French patients who had GBS, an autoimmune disorder that causes neurologic symptoms, from March 2007 through June 2010 and matched them with 1,080 controls. They found that seasonal or pandemic H1N1 influenza or influenza-like illness more than doubled (odds ratio = 2.3) the risk of developing GBS. In addition, the difference in GBS rates when flu viruses were circulating and when they weren't was highly statistically significant (P = 0.004). In contrast, the adjusted odds ratios for GBS within 6 weeks after seasonal and H1N1 vaccination were 1.3 and 0.9, respectively. The authors conclude, "Study results confirm that influenza virus is a likely risk factor for GBS. Conversely, no new concerns have arisen regarding influenza vaccination."
Jun 7 Am J Epidemiol abstract
'Snow birds' bring pneumonia, influenza south with them
Researchers studying US pneumonia and influenza (P&I) burden in seniors found that typical winter destination states such as Florida, Arizona, California, and Texas experience a significant jump in nonresident P&I hospitalizations during the traditional flu season of October through March. The researchers, from Tufts University in Boston, synthesized data on all US Medicare-eligible hospitalizations in patients 65 and older from 1991 through 2006. Although most states experienced a higher proportion of nonresident P&I during the summer, Sun Belt states had higher nonresident P&I during the traditional peak influenza season. Florida, for example, had nearly 15% of its P&I load represented by out-of-state visitors during these months, which, the authors write, could profoundly affect the local healthcare system. They conclude that awareness of this trend "will allow state and local health officials to plan for localized outbreaks and timely changes in health care services utilization."
Jun 7 BMC Public Health abstract
Statistical analysis shows flu may predispose patients to pneumonia
In other P&I news, Toronto researchers demonstrated a short-term time-lag association between influenza infection and invasive pneumococcal disease (IPD), which they say supports the hypothesis that influenza raises the short-term risk of bacterial infection. They evaluated 38,501 positive influenza tests in central Ontario and 6,191 episodes of IPD in the Toronto area from Jan 1, 1995, to Oct 3, 2009. They used statistical analysis to determine long- and short-term relationships between the two diseases. They found no direct correlation in the long term, but two statistical methods (negative binomial regression and case crossover) showed a 1-week-lag association between the flu and IPD. "Our data support the hypothesis," the authors write, "that influenza influences bacterial disease incidence by enhancing short-term risk of invasion in colonized individuals."
Jun 7 PLoS Med study
Pakistan shutters avian flu–prevention program
Pakistan's government has flouted the advice of an avian flu steering committee and its Planning and Development Division and decided to discontinue its National Programme for the Control and Prevention of Avian Influenza (NPCPAI), the country's Daily Times reported today. Sources said that, with the demise of the NPCPAI, Pakistan will not be able to fight avian flu and will lose its World Organization for Animal Health (OIE) declaration of being free of avian flu, according to the story. The last H5N1 avian flu outbreak that Pakistan reported to the OIE was in 2008. The last human case in the country was confirmed in 2007.
Jun 8 Daily Times story