Measles immunity in the China-Myanmar border region, Lincang city, Yunnan province, 2017

Seroprevalence of Measles Antibodies Among Migrant Populations: A Systematic Review and Meta-Analysis

Incomplete or interrupted vaccination schedules put migrant communities at higher risk for measles, which remains a serious public health concern. The objective of this systematic review was to evaluate the pooled seroprevalence of measles antibodies among migrant groups globally and offer data to guide public health initiatives. Our literature search included PubMed, Scopus, and Embase databases, covering publications from 1990 to 2023, and was systematically refined using specific inclusion and exclusion criteria. Only observational studies documenting measles antibody seroprevalence among defined migrant groups were included to ensure relevance and quality in addressing the study's objective. Meta-analytical techniques such as random-effects models were employed to assess pooled seroprevalence. The meta-analysis comprised 36 studies with 42,972 participants in total. Among migrant communities, the overall pooled seroprevalence of measles antibodies was 83% (95%CI: 80%-87%). Studies showed significant heterogeneity (I2 = 98%, p < 0.01). According to meta-regression analysis, measles seroprevalence has been gradually increasing in more recent research, and time (year) was a significant predictor of seroprevalence variability (p < 0.05). Measles seroprevalence in migratory communities is still below the threshold for herd immunity, especially in susceptible populations like children and refugees. To close these immunity gaps and stop future outbreaks in host nations, focused public health interventions such as catch-up vaccination programs are desperately needed.

Evaluation of measles vaccination coverage in Lincang City, Yunnan Province, China

Background: Lincang City in Yunnan Province on the China-Myanmar border, has reached the World Health Organization recommended coverage (95%) for measles-containing vaccine (MCV), but measles outbreaks still occur. We conducted a survey in Lincang City to determine the measles vaccination status of children on the China-Myanmar border.Methods: We used multistage sampling among children aged 8-83 months. Information on measles vaccination status was obtained from the child's vaccination certificate, and serum samples were tested using commercially available ELISA kits.Results: A total of 938 children were surveyed. The vaccination coverage rate was 98.9% (95% CI: 98.2-99.6%) for measles-containing vaccine dose 1 (MCV1), and 95.8% (95% CI:94.9-96.7%) for measles-containing vaccine dose 2 (MCV2). The timely vaccination coverage rate was 52.0% (95% CI:48.8-55.2%) for MCV1, and 74.1% (95% CI: 82.9-89.0%) for MCV2. The timely-and-complete vaccination coverage rate was 41.0% (95% CI: 36.7-45.3%). The median delay period was 33 (95% CI: 27-39) days for MCV1, and 196 (95% CI: 146-246) days for MCV2. The seropositivity rate in children aged less than 7 years was 94.0% (95% CI: 92.5-95.5%) with a geometric mean titer of 1210.1 mIU/mL.Conclusions: The MCV coverage was high, but timely and timely-and-complete vaccination coverage were low and insufficient to prevent measles outbreaks. It is necessary to add the timely and timely-and-complete vaccination coverage as indicators of vaccination to provide a more complete picture of measles immunization status.