Epidemiological characteristics and serological survey of mumps 15 years after MMR vaccine was included in the immunization program.

Mumps is a vaccine-preventable acute viral infectious disease. To understand the incidence of mumps and population immunity in Quzhou City after measles mumps rubella vaccine (MMR) was included in the immunization program, we analyzed the epidemiological characteristics of mumps cases from 2009 to 2023 and a cross-sectional serosurvey of IgG antibodies to mumps conducted in 2024. We found that 15 years after the MMR vaccine was included in the immunization program, the incidence of mumps was significantly reduced in all populations, but the incidence remained highest in vaccinated children aged 0-12 years. Vaccine escape may explain the high incidence of mumps in highly vaccinated populations. Updating vaccines or developing a new vaccine that targets multiple viral genotypes may be necessary to improve the effectiveness of the vaccine against infection and fully control infections and outbreaks. The positive rate and concentration of mumps IgG antibody were inconsistent with the incidence data. mumps IgG antibody is not an ideal substitute for immunity and cannot be used to accurately predict whether a target population is susceptible or protected. Natural infections may provide longer-lasting immunity than vaccination.

Mild-to-moderate iodine deficiency in a sample of pregnant women and salt iodine concentration from Zhejiang province, China.

Since 2011, Zhejiang province has eliminated iodine deficiency disorders (IDD) in its populations. Following this achievement, a new revised iodine concentration in iodised salt was implemented in Zhejiang in 2012. However, the re-emergence of iodine deficiency has been reported in pregnant women. Therefore, the aim of this study was to assess household salt iodine concentration and iodine status of pregnant women in Zhejiang province, China. We conducted a cross-sectional study between April 2018 and August 2018 in Quzhou, Zhejiang province. Pregnant women aged ≥ 18 years who did not have a history of thyroid disease were recruited into the study. They were asked to complete socio-demographic questionnaires including a food frequency questionnaire (FFQ). In addition, a spot urine sample and a household table salt sample were also provided by each participant. A total of 625 pregnant women agreed to participate. The overall median urinary iodine concentration (UIC) was 130 µg/L, indicating mild-to-moderate iodine deficiency in pregnant women. The coverage of iodised salt was 85.2%, and of these, the rate of adequately iodised salt was 98.1%. In conclusion, our results confirmed the re-emergence of iodine deficiency in pregnant women as reported by other studies conducted in Zhejiang province. Therefore, urgent public health actions are needed to improve iodine status of pregnant women in order to prevent the adverse consequences of IDD on the neurodevelopment of foetus.