Immunogenicity of the AIK-C measles vaccine in infants aged <9 months in Vietnam.

Measles-associated deaths have been reported in infants <9 months during outbreaks. A cohort study was conducted on 210 infants aged 6-8 months to evaluate the immunogenicity and safety of the AIK-C measles vaccine containing 104.21 plaque-forming units (PFU)/0.5 mL produced in Vietnam. Paired serum samples were obtained from 196 subjects. Seropositivity was defined as ≥120 mIU/mL. The seroresponse rate was 173/196 (88.27%, 95% confidence interval (CI): 83.77-92.77%) with geometric mean titer (GMT) of 511 mIU/mL (95% CI: 688-880 mIU/mL), and no significant differences were observed by different age groups. Among 196 paired sera, they were categorized into four groups: 122 subjects <14 IU/mL, 28 subjects 14-<60 mIU/mL, 30 subjects 60-<120 mIU/mL, and 16 subjects ≥ 120 mIU/mL. The seroresponse rate was 112/122 (91.8%, 95% CI: 86.94-96.67%) with GMT (597 mIU/mL, 95% CI: 749-1002 mIU/mL) in the <14 mIU/L group. In the 14-<60 mIU/mL group, the seroresponse rate was 18/28 (64.29%) with 184 mIU/L of GMT and was significantly lower (p < 0.01) than that in the <14 mIU/mL group. In the 16 seropositive group, all subjects showed seroconversion (4-fold higher than before) with a higher GMT of 1078 mIU/mL. Local pain and itching at the injection site were observed in 8 subjects (3.8%) within 7 days of the vaccination. Regarding systemic adverse reactions, febrile illness ≥37.5 °C was observed in 14 subjects (6.7%). These results indicate that the AIK-C measles vaccine is effective and safe for infants aged 6-8 months and will contribute to reducing the number of measles-associated deaths in future outbreaks.

Disability from Japanese encephalitis in Cambodia and Viet Nam.

A cohort of Japanese encephalitis (JE) survivors in Cambodia and Viet Nam were assessed at least 4 months after hospital discharge in order to understand the extent of disability after JE. We used a simple assessment tool which focuses on the impact on daily life. In total, 64 disability assessments were conducted: 38 in Cambodia and 26 in Viet Nam. In Cambodia, 4 (11%) children had severe sequelae, suggesting the children would likely be dependent, 15 (39%) had moderate sequelae and 17 (45%) had mild sequelae. In Viet Nam, two (8%) persons had severe sequelae, five (19%) had moderate sequelae and eight (31%) had mild sequelae. In many JE-endemic areas there are no multi-disciplinary teams with sophisticated equipment to assess patients after JE disease. This assessment tool can assist with patient management and generate data to support the need for programmes to prevent disease and improve outcomes for survivors.