Prior to 2009 dengue fever had not been reported in the Andaman and Nicobar archipelago. In 2009, a few patients with dengue fever-like illness were reported, some of whom tested positive for dengue antibodies. In 2010, 516 suspected cases were reported, including some with dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS); 80 (15·5%) were positive for dengue antibodies. DENV RNA was detected in five patients and PCR-based typing showed that three of these belonged to serotype 1 and two to serotype 2. This was confirmed by sequence typing. Two clones of dengue virus, one belonging to serotype 1 and the other to serotype 2 appeared to be circulating in Andaman. Emergence of severe diseases such as DHF and DSS might be due to recent introduction of a more virulent strain or because of the enhancing effect of sub-neutralizing levels of antibodies developed due to prior infections. There is a need to revise the vector-borne disease surveillance system in the islands.

An increase in invasive Haemophilus influenzae type b (Hib) cases occurred in Minnesota in 2008 after the recommended deferral of the 12–15 months Hib vaccine boosters during a US vaccine shortage. Five invasive Hib cases (one death) occurred in children; four had incomplete Hib vaccination (three refused/delayed); one was immunodeficient. Subsequently, we evaluated Hib carriage and vaccination. From 18 clinics near Hib cases, children (aged 4 weeks–60 months) were surveyed for pharyngeal Hib carriage. Records were compared for Hib, diphtheria-tetanus-acellular pertussis (DTaP), and pneumococcal (PCV-7) vaccination. Parents completed questionnaires on carriage risk factors and vaccination beliefs. In 1631 children (February–March 2009), no Hib carriage was detected; Hib vaccination was less likely to be completed than DTaP and PCV-7. Non-type b H. influenzae, detected in 245 (15%) children, was associated with: male sex, age 24–60 months, daycare attendance >15 h/week, a household smoker, and Asian/Pacific Islander race/ethnicity. In 2009, invasive Hib disease occurred in two children caused by the same strain that circulated in 2008. Hib remains a risk for vulnerable/unvaccinated children, although Hib carriage is not widespread in young children.