{Reference Type}: Journal Article
{Title}: Age-specific prevalence of IgG against measles/rubella and the impact of routine and supplementary immunization activities: A multistage random cluster sampling study with mathematical modelling.
{Author}: Hachiya M;Vynnycky E;Mori Y;Do HT;Huynh MK;Trinh LH;Nguyen DD;Tran NAT;Hoang TT;Hoang HHT;Vo NDT;Le TH;Ichimura Y;Miyano S;Okawa S;Thandar MM;Yokobori Y;Inoue Y;Mizoue T;Takeda M;Komada K;
{Journal}: Int J Infect Dis
{Volume}: 144
{Issue}: 0
{Year}: 2024 Jul 17
{Factor}: 12.074
{DOI}: 10.1016/j.ijid.2024.107053
{Abstract}: <B>BACKGROUND: </B>Vietnam continues to have measles and rubella outbreaks following supplementary immunization activities (SIA) and routine immunization despite both having high reported coverage. To evaluate immunization activities, age-specific immunity against measles and rubella, and the number of averted Congenital Rubella Syndrome (CRS) cases, must be estimated.<BR><B>METHODS: </B>Dried blood spots were collected from 2091 randomly selected individuals aged 1-39 years. Measles and rubella virus-specific immunoglobulin G (IgG) were measured by enzyme immunoassay. Results were considered positive at ≥120 mIU/mL for measles and ≥10 IU/mL for rubella. The number of CRS cases averted by immunization since 2014 were estimated using mathematical modelling.<BR><B>RESULTS: </B>Overall IgG seroprevalence was 99.7% (95%CI: 99.2-99.9) for measles and 83.6% (95%CI: 79.3-87.1) for rubella. Rubella IgG seroprevalence was higher among age groups targeted in the SIA than in non-targeted young adults (95.4% [95%CI: 92.9-97.0] vs 72.4% [95%CI: 63.1-80.1]; P < 0.001). The estimated number of CRS cases averted in 2019 by immunization activities since 2014 ranged from 126 (95%CI: 0-460) to 883 (95%CI: 0-2271) depending on the assumed postvaccination reduction in the force of infection.<BR><B>CONCLUSIONS: </B>The results suggest the SIA was effective, while young adults born before 1998 who remain unprotected for rubella require further vaccination.