Pandemic (H1N1) 2009 in Neonates, Japan

of carriage may refl ect a nationwide change (8). Furthermore, testing within the fi rst week of term meant that recovered strains were predominately brought into the university. Serogroup Y carriage rates for incoming students (2.9%) were signifi cantly higher than rates detected by identical genotyping methods during 1999–2001 (1.7%– 1.8% [4]; χ2 = 4.6%–6.4%, 1 df; p<0.05), suggesting that meningococcal carriage by young adults, particularly of serogroup Y strains, has increased across the United Kingdom. The major increase in serogroup Y strains among fi rst-year students during 2009–10 probably resulted from spread of clones within dormitories, as observed in the 2008–9 study (5) and may be facilitated by characteristics of the organism, lack of immunity, or a combination of these factors. The high prevalence of serogroup Y strains in carriers may help explain the recent increased incidence of serogroup Y disease in the United Kingdom: from 20 to 62 laboratoryconfi rmed cases in England and Wales from 2003 through 2009 (9). In the United States during the late 1990s, a similar increase in serogroup Y carriage was linked to a concomitant increase in serogroup Y disease (10). In conclusion, in a representative UK student cohort we detected high rates of carriage and elevated prevalence of serogroup Y strains of meningococci. Any further signifi cant increase in serogroup Y disease should lead to prompt reconsideration of the current vaccine policy in the United Kingdom.