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The authors discuss a study led by Feng-Cai Zhu and published within the issue, regarding a phase 2 clinical trial of an inactivated enterovirus 71 (EV71) vaccine to prevent severe outcomes of EV71 infection in young children. It mentions the large number of deaths in Asia caused by EV71 infections. The possibility that the vaccine's immunogenicity may have been overestimated is also addressed.

Background. The Strategic Advisory Group of Experts on Immunization (SAGE) has recommended introduction of at least 1 dose of inactivated poliovirus vaccine (IPV) at ≥14 weeks of age through the routine immunization program in countries currently not using IPV.Methods. We analyzed all available unrestricted data obtained from the Demographic and Health Surveys since 2005 in sub-Saharan Africa (31 countries) and in South and Southeast Asia (9 countries) to determine coverage of the following injectable vaccines delivered through the routine immunization schedule: diphtheria-tetanus-pertussis vaccine dose 1 (DTP1), DTP2, DTP3, and measles vaccine. Coverage with these vaccines was used as a proxy measure of likely 1- and 2-dose IPV coverage.Results. Coverage with 1 dose of IPV is expected to be lowest when offered with DTP3 (median coverage, 73%) and highest when offered with DTP1 (median coverage, 90%). The median DTP1-DTP3 drop-out rate was 14%, which equates to an additional 12 million children not receiving IPV if IPV is offered with DTP3, rather than with DTP1. An increased geographical clustering of children who have not received IPV is expected in sub-Saharan Africa and Asia if IPV is offered with DTP3, rather than with DTP1. Coverage with 2 doses of IPV is expected to be lowest if IPV is administered with DTP3 and measles vaccine (69%) and highest if administered with DTP1 and DTP2 (84%).Conclusions. Coverage with 1 dose of IPV is expected to be lowest if it is administered at the DTP3 visit. At present, there is insufficient evidence to determine whether the SAGE-recommended IPV schedule for the polio endgame would maximize population immunity to type 2 poliovirus. [ABSTRACT FROM PUBLISHER]

In 2001, increased activity of the rarely detected enterovirus echovirus type 13 (E13) was observed in the United States. This article describes the epidemiologic, clinical, and genetic characteristics of E13 activity in the United States in 2001, compared with E13 activity abroad in 2000-2002. In the United States, E13 accounted for 376 (24%) of the 1584 enterovirus isolates reported in 2001 (29% of the reported isolates had a known serotype), compared with 74 isolates reported during 1970-2000. Five states reported aseptic meningitis outbreaks associated with E13, for a total of 521 cases. All characterized E13 isolates from the United States, Europe, Asia, and Oceania recovered in 2000-2002 were at least 95% identical to each other in VP1 capsid gene sequence, but they were genetically distinct from E13 isolates recovered before 2000. Continued surveillance of enteroviruses is important to alert physicians and public health officials to changes in disease trends and to improve efficiencies of clinical intervention.

Echovirus 11 (E11) is among the most commonly isolated human enteroviruses. To examine the range of genetic variation within the E11 serotype, we determined the complete VP1 sequences for 53 geographically dispersed E11 strains isolated in 16 countries from 1953 to 2001. E11 sequences were monophyletic with respect to all other enterovirus serotypes. The sequences clustered into four monophyletic genogroups, A-D; members of each genogroup differed from one another by <20%. Isolates in different genogroups differed from one another by 19-28%. The E11 prototype strain, USA/CA53-Gregory, was the sole member of genogroup B. All recent US isolates were members of one of two discrete lineages within genogroup D. The well-characterized E11 antigenic variant, USA/CA63-Silva, was also a member of genogroup D. Members of genogroups A and C were antigenically similar to USA/CA53-Gregory, as measured by neutralization with anti-Gregory and anti-Silva antisera. Only USA/CA63-Silva was neutralized more efficiently by the anti-Silva antiserum; other genogroup D viruses were Gregory-like or intermediate in their neutralization phenotype. Recent non-US isolates were distributed in genogroups A, C and D. Sequence similarities among genogroup D isolates from North America, Europe, Asia, Australia and North Africa demonstrate that an E11 strain can spread rapidly over a wide geographic area. The aligned sequences were used to develop an E11-specific RT-PCR assay, using degenerate, inosine-containing primers, to amplify all members of all genogroups.