The immunogenicity and safety of the tetravalent meningococcal serogroups A, C, W-135, and Y tetanus toxoid conjugate vaccine (MenACWY-TT) were evaluated in subjects previously vaccinated with a tetravalent meningococcal polysaccharide vaccine and in subjects without previous meningococcal vaccination. Methods: In this phase II, open, controlled study (NCT00661557), healthy subjects aged 4.5-34 years received one dose of MenACWY-TT at month 0. Subjects in the MPS group (n = 192) had received polysaccharide vaccine in a study conducted 30-42 months earlier; age-matched subjects in the noMPS control group (n = 79) had received no meningococcal vaccination within the past 10 years. Serum bactericidal activity using rabbit complement (rSBA) was measured at month 0 and month 1. Results: At month 1, 97.0% of subjects had rSBA titers 1:128. Post-vaccination rSBA geometric mean titers (GMTs) were 3.9-fold higher than pre-vaccination in both treatment groups. Exploratory analyses showed no statistically significant differences between groups in percentages of subjects with rSBA titers 1:8 and 1:128, but significantly lower rSBA GMTs and vaccine response rates for each serogroup in the MPS versus the noMPS group. MenACWY-TT had an acceptable safety profile in both groups. Conclusions: These results suggest that MenACWY-TT could be used in vaccination programs irrespective of the pre-vaccination status with polysaccharide vaccine.

The emergence of antiviral drug-resistant strains of the influenza virus in addition to the rapid spread of the recent pandemic A(H1N1) 2009 virus highlight the importance of surveillance of influenza in identifying new variants as they appear. In this study, genetic characteristics and antiviral susceptibility patterns of influenza samples collected in Lebanon during the 2008-09 season were investigated. Forty influenza virus samples were isolated from 89 nasopharyngeal swabs obtained from patients with influenza-like illness. Of these samples, 33 (82.5%) were A(H3N2), 3 (7.5%) were A(H1N1), and 4 (10%) were B. All the H3N2 viruses were resistant to amantadine but were sensitive to oseltamivir and zanamivir; while all the H1N1 viruses were resistant to oseltamivir (possessed H275Y mutation, N1 numbering, in their NA) but were sensitive to amantadine and zanamivir. In the case of influenza B, both Victoria and Yamagata lineages were identified (three and one isolates each, respectively) and they showed decreased susceptibility to oseltamivir and zanamivir when compared to influenza A viruses. Influenza circulation patterns in Lebanon were very similar to those in Europe during the same season. Continued surveillance is important to fully elucidate influenza patterns in Lebanon and the Middle East in general, especially in light of the current influenza pandemic.