Background Influenza vaccine effectiveness (VE) can vary by type and subtype. Over the
past decade, the test-negative design has emerged as a valid method for estimation of VE …

Background. The predominant strain during the 2013–2014 influenza season was 2009
pandemic influenza A (H1N1) virus (A [H1N1] pdm09). This vaccine-component has …

Background. Antibody titers decrease with time following influenza vaccination, raising
concerns that vaccine efficacy might wane. However, the relationship between time since …

Background Observational studies of influenza vaccine effectiveness (VE) are increasingly
using the test-negative design. Studies are typically based in outpatient or inpatient settings …

Background. Recent studies suggest that statin use may reduce influenza vaccine
effectiveness (VE), but laboratory-confirmed influenza was not assessed. Methods …

abstract Background. Older adults are at increased risk of influenza-associated
complications, including hospitalization, but influenza vaccine effectiveness (VE) data are …

Background Influenza vaccine effectiveness (VE) is increasingly estimated using the case-
test negative study design. Cases have a symptom complex consistent with influenza and …

Background Infants are at high risk for influenza illness, but are ineligible for vaccination
before 6 months. Transfer of maternal antibodies to the fetus has been demonstrated for …

Influenza is a communicable acute respiratory disease and one of the major infectious
disease threats to the human population. Influenza virus affects individuals of all ages …

Background: Assessing seasonal severity of influenza is problematic; traditional indicators
may not be reliable to determine the magnitude of each influenza season. We investigated …