Study: Oseltamivir shortens flu symptom duration but not viral shedding
Oseltamivir (Tamiflu) taken within 24 hours of flu symptom onset shortened the duration of all symptoms by 56%, but had no effect on household flu transmission or viral shedding, according to a study yesterday in the Journal of Infectious Diseases.
The observational study comprised 582 people with lab-confirmed influenza and their household members living in Hong Kong from 2008 to 2013. Children under 5 years old made up 21% (121) of the study population, while 43% (250) were children from 6 to 12.
Researchers from the University of Hong Kong and the Harvard University School of Public Health found that patients who took oseltamivir within 24 hours of flu symptom onset experienced a 56% reduction in their duration of symptoms (95% confidence interval (CI), 41%-67%).
Oseltamivir reduced fever duration by 47% (95% CI, 45%-63%) and reduced respiratory symptom duration by 56% (95% CI, 33%-59%).
The study did not find an association between oseltamivir use and the patient's infectivity or viral shedding in his or her household. Of the 1,420 household contacts of 467 patients, 139 (9.8%) were infected with influenza.
The authors say that limitations to the study include the small sample size and the fact that viral shedding was measured by reverse transcriptase polymerase chain reaction (PCR), so viral presence could only be confirmed in the nose and throat.
Feb 2 J Infec Dis study
Study: Obese elderly have greater risk of flu-related death
Obese elderly people have a greater risk of death related to respiratory symptoms during flu seasons, regardless of body mass comorbidities and other risk factors, according to a study yesterday in Clinical Infectious Diseases.
The population-based cohort study involved 66,820 Chinese people age 65 and older receiving services at Elderly Health Centres in Hong Kong from 1998 through 2012.
Before the 2009 H1N1 flu pandemic, obese elderly people were 19% more likely to die of respiratory causes during flu seasons when compared with normal-weight people (hazard ratio [HR], 1.19; 95% CI, 1.01-1.42). The association between flu and mortality was 11% higher for obese elderly people from 2009 to 2012 (HR, 1.11; 95% CI, 1.01-1.22).
Increased risk remained the same even when adjusted for age, health status, presence of other circulating respiratory viruses, and comorbidities like chronic illness, smoking, or alcohol abuse, the researchers note.
They also stratified mortality risk for obese sub-groups by the time between influenza infection and death (the lag in weeks). Obese people in good health were 35% more likely to die from influenza than normal-weight people during a 5-week lag (HR, 1.35; 95% CI, 0.97-1.87). Obese people in poor health were 21% more likely to die during a 1-week lag compared with their normal-weight counterparts (HR, 1.21; 95% CI, 1.00-1.46).
The study estimated that 26.1% to 36.4% of elderly community-dwelling people in Hong Kong are vaccinated for influenza and suggested further prioritizing flu vaccine and preventive outreach for obese older people.
Feb 2 Clin Infect Dis study
