Sero-epidemiological study in prediction of the risk groups for measles outbreaks in Vojvodina, Serbia

Abstract

Background Age-stratified serologic surveys provide insight into the gaps of measles-specific immunity as well as estimates of the age-specific seroprevalence. The aim of this study was to describe the measles sero-epidemiology in Vojvodina before the occurrence of outbreak in 2017/18 and to discuss preventive measures for potential future epidemics. Methods A seroprevalence study was conducted from April 2015 to June 2017 on serum bank of 3199 residual samples. Study was performed prior to the last measles outbreak in Vojvodina that occurred between 12th November 2017 and 30th June 2018. Measles-specific IgG antibodies were determined using an indirect chemiluminescent immunoassay (CLIA). Results Median age of enrolled participants was 20 years (IQR 11–37). Overall, 86.9% serum samples were seropositive. The highest proportion of measles seronegativity was observed in children aged 12–23 months of age and in adults aged 20–39 years (56.1% and 18.5%, respectively). Prevalence of measles seronegativity above WHO target levels susceptibility was observed in the following age groups: 2, 7, 13, 15, and among all adults aged between 20 and 49 years. Out of total measles outbreak cases (177), there were 91 (51.4%) participants aged 20–39 years. A significant positive correlation was observed between measles seronegativity and the number of reported measles cases aged ≥ 12 months (r = 0.4675, p = 0.0213). Conclusions In order to prevent new outbreaks and achieve the elimination of measles in Vojvodina, the vaccination coverage of both measles-mumps-rubella (MMR1 and MMR2) vaccines needs to be improved and sustained. Educational campaigns for the improvement of acceptance and timely vaccination with vaccine against measles among doctors and the general population are crucial. Our results indicate possible gap in measles protection in adults born during implementation of one dose of measles vaccine and prioritize supplementary immunization activities targeting adults in Vojvodina, Serbia.

Seroprevalence of IgG antibodies against measles in a selected Polish population – do we need to be re-vaccinated?

“…We observed that a group of patients who were covered by immunization schedule had significantly lower titres of antibodies against measles that a non-vaccinated older group, which is consistent with the results from previous studies [3,8,13,15]. Also, our results showed a similar distribution of anti-measles IgG among different age groups as shown by Ristic et al [13]. Here, we observed the same trend of decreasing measles-specific IgG titer over time from vaccination, as reported by Kennedy et al [7]; however, there was a longer time between possible vaccination and serological test in our study (up to 40 vs. 17 years).…”

“…Higher immunization status in women might be associated with additional vaccination against rubella, which was administered together with vaccine against mumps and measles later in childhood. We observed an alarming susceptibility to disease in 56/149 (37.58%) individuals who were 19-45 years old, and this rate is almost twice that reported in other studies [3,13,18] and similar to the results reported in studies conducted in South Korea, Italy, and Czech Republic [14,15,19]. These data strongly suggest that this age group is at particular risk of possible infection and should be re-vaccinated.…”

“…In addition, the seropositivity ratio was the highest in all groups, which were not vaccinated due to natural immunization caused by the disease. Nevertheless, the number of seropositive subjects was quite low compared with that of other European studies [2,3,13], which does not confirm that immunogenicity from the measles vaccine has life-long effects [14]. We observed that a group of patients who were covered by immunization schedule had significantly lower titres of antibodies against measles that a non-vaccinated older group, which is consistent with the results from previous studies [3,8,13,15].…”

“…Nevertheless, the number of seropositive subjects was quite low compared with that of other European studies [2,3,13], which does not confirm that immunogenicity from the measles vaccine has life-long effects [14]. We observed that a group of patients who were covered by immunization schedule had significantly lower titres of antibodies against measles that a non-vaccinated older group, which is consistent with the results from previous studies [3,8,13,15]. Also, our results showed a similar distribution of anti-measles IgG among different age groups as shown by Ristic et al [13].…”

Seroepidemiological study of rubella in Vojvodina, Serbia: 24 years after the introduction of the MMR vaccine in the national immunization programme

“…the MMR vaccine in Serbia from 2012-2016, as well as an increased activity and media presence of the anti-vaccination movement in the Balkan countries, which has contributed to a surge in vaccine scepticism and vaccine hesitancy [6,24,25]. Maintaining such a negative trend in immunization coverage leads to an increase in the number of susceptible populations.…”