Serological test results of suspected measles and rubella cases in Hebei province from 2020 to 2024: a study based on routine surveillance data

Objective To analyze the detection status and epidemiological characteristics of immunoglobulin M (IgM) antibodies of suspected measles and rubella cases in Hebei province from 2020 to 2024, thus providing technical support for optimizing the prevention and control strategies.

Methods Enzyme-linked immunosorbent assay (ELISA) was employed to detect IgM antibodies in the serum samples of suspected measles and rubella cases in Hebei province from January 1, 2020 to December 31, 2024, and the test results were analyzed.

Results A total of 8 064 serum samples were tested. Among them, 214 (2.65%) were positive for measles IgM antibodies, and 80 (0.99%) were positive for rubella IgM antibodies. The years 2020, 2021, 2022, 2023, and 2024 showed the annual positive rates of measles IgM antibodies being 5.38%, 2.70%, 2.05%, 1.89%, and 1.58% and the annual positive rates of rubella IgM antibodies being 2.30%, 0.97%, 0.85%, 0.54%, and 0.47%, respectively. The IgM antibody positive rates of both measles and rubella showed a declining trend from 2020 to 2024 (all P < 0.001). From 2020 to 2024, positive cases of both measles and rubella were detected among the suspected cases every month. The highest monthly positive rates for both measles (18.67%) and rubella (12.03%) occurred in January. Geographically, Cangzhou city had the highest measles IgM positive rate (4.73%), while Qinhuangdao city had the highest rubella IgM positive rate (4.21%). No significant gender difference (P > 0.05) was observed in the IgM antibody positive rate for measles (2.75% in males vs. 2.54% in females) or rubella (1.11% in males vs. 0.86% in females). Age-specific analysis revealed significant variations (P < 0.001). Specifically, the age groups of < 8 months, 8 months to 4 years, 5 to 9 years, 10 to 19 years, and ≥ 20 years showed the IgM antibody positive rates of measles being 3.77%, 3.95%, 1.45%, 1.99%, and 1.40% and the IgM antibody positive rates of rubella being 0.94%, 0.70%, 0.65%, 4.47%, and 0.75%, respectively. The IgM antibody positive rates of measles in suspected cases with no vaccination, one-dose vaccination, and two-dose vaccination were 2.80%, 8.46%, and 0.79%, respectively, showing significant differences (χ² = 209.186, P < 0.001). The IgM antibody positive rates of rubella in suspected cases with no vaccination, one-dose vaccination, and two-dose vaccination were 1.16%, 1.34%, and 0.76%, respectively, showing no significant difference (P > 0.05).

Conclusions The IgM antibody positive rates of measles and rubella in suspected cases in Hebei province consistently declined from 2020 to 2024, being the highest in January. Cangzhou and Qinhuangdao were identified as key areas for the prevention and control of measles and rubella, respectively. Measles prevention should prioritize younger age groups and individuals who have not completed the full vaccination course, whereas rubella prevention efforts should focus on the population of 10 - 19 years old.