Burden of invasive disease caused by Haemophilus influenzae type b in Asia.

Globally, Haemophilus influenzae type b (Hib) is one of the leading causes of childhood meningitis and pneumonia. Vaccines against Hib have been developed and introduced into routine immunization programs in most industrialized nations, in which the burden of Hib disease has been clearly demonstrated. In Asia, the burden of Hib disease has been perceived as relatively low compared with other parts of the world. However, the results of several recent studies have allowed for a more cautious assessment of the disease burden in different populations and settings throughout Asia. These studies suggest that the true burden of Hib disease may have been underestimated, and point to several key factors that may have contributed to this problem, such as antibiotic use prior to the analysis of blood and cerebrospinal fluid in infants and children suspected of having invasive Hib disease. Trials evaluating Hib vaccines in Asian populations have shown that they are effective and safe. These results may aid in the decision about whether to implement routine Hib vaccination in Asia and help to track the impact of Hib vaccination in the future.