Measles and rubella serosurvey identifies rubella immunity gap in young adults of childbearing age in Zambia: The added value of nesting a serological survey within a post-campaign coverage evaluation survey.

Serological surveys can potentially complement vaccine coverage surveys, such as post-vaccination campaign coverage evaluation surveys (PCES), by providing direct information on population immunity within and outside the target age range of the mass vaccination campaign. We estimate age-specific population immunity to measles and rubella viruses in Southern Province, Zambia, and assess the value of adding serological data to vaccination coverage estimates by nesting a serological survey within a PCES. Dried blood spots (DBS) from fingerprick blood were collected from all individuals ages nine months or older in households participating in the PCES and tested for measles and rubella virus-specific immunoglobulin G (IgG) by enzyme immunoassay (Siemens Enzygnost, Marburg, Germany). Overall seroprevalence was 95.5% (95% CI: 92.8, 97.2) for measles virus-specific IgG and 97.7% (95% CI: 96.0, 98.7) for rubella virus-specific IgG. Rubella seroprevalence was 98.4% (95% CI: 95.9, 99.4) among children eligible for the MR vaccination campaign, significantly higher than the reported measles-rubella (MR) vaccination campaign coverage of 89.8% (p = 0.003), and higher than the 91.3% rubella seroprevalence for adolescents and adults 16-30 years of age (p = 0.049). Seroprevalence to measles and rubella viruses in children younger than 16 years of age was significantly higher than expected from vaccination coverage estimates, likely reflecting exposure to wild-type viruses and underreporting of vaccination. The serosurvey revealed rubella immunity gaps among women 16-30 years of age, precisely the age group in which protection from rubella is most important to prevent congenital rubella syndrome. Nesting serological surveys within existing surveys can leverage resources and infrastructure while providing complementary information important to immunization programs.

Hayford K ，Mutembo S ，Carcelen A ，Matakala HK ，Munachoonga P ，Winter A ，Wanyiri JW ，Searle K ，Mwansa FD ，Mwiche A ，Phiri C ，Book C ，Thuma PE ，Moss WJ ... -  《-》

Integrating Blood Collection within Household Surveys: Lessons Learned from Nesting a Measles and Rubella Serological Survey within a Post-Campaign Coverage Evaluation Survey in Southern Province, Zambia.

Mutembo S ，Carcelen A ，Mwansa FD ，Searle K ，Wanyiri JW ，Book C ，Thuma PE ，Moss WJ ，Hayford K ... -  《-》

Impact of a Measles and Rubella Vaccination Campaign on Seroprevalence in Southern Province, Zambia.

Carcelen AC ，Mutembo S ，Matakala KH ，Chilumba I ，Mulundu G ，Monze M ，Mwansa FD ，Moss WJ ，Hayford K ... -  《-》

How much does it cost to measure immunity? A costing analysis of a measles and rubella serosurvey in southern Zambia.

Carcelen AC ，Hayford K ，Moss WJ ，Book C ，Thuma PE ，Mwansa FD ，Patenaude B ... -  《-》

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.

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. 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. 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. The results suggest the SIA was effective, while young adults born before 1998 who remain unprotected for rubella require further vaccination.

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 ... -  《-》