| Sub-title | |
| Authors | G Zahra C Barbara |
| Abstract | Background: To analyse progress in measles control it is recommended that immunisation be evaluated by means of specific epidemiological disease surveillance. Knowing the prevalence of measles by serologic markers is an important toll to assess the risk of measles outbreaks thus providing crucial information if our current prevention strategies for this endemic disease need refinement. Methods: A laboratory based population of 920 sera including a group of hospital workers was assessed from persons of 6 years of age or older with 5 year birth cohorts between each age group. Five birth cohorts were examined instead of age groups to capture temporal changes in susceptibility as major policy changes occurred during the 3 decades after the measles vaccine was licensed. The sera were tested for measles specific IgG antibody by enzyme immunoassay. Sera positive for measles IgG were considered protected or immune to measles disease. Exact 95 % confidence intervals (CI) was calculated for prevalence estimates. Results: Prevalence of measles immunity was found to be 95% [95% CI 94 to 95%] suggesting that herd immunity has been achieved. Immunity was higher in persons born during the pre-vaccine era 99% [95% CI98 To 99%] than those born during the vaccine era 93%[95% CI 92 to 94%]. Decline in immunity was seen in school aged children (6-10yrs) were immunity was 83%[95% CI 78 to 87%]. In general the overall pattern of immunity was consistent for all groups with no difference in immunity between males and females. Conclusions: Improvement in vaccination coverage at 4-6 years as indicated by study might increase the prevalence of herd immunity in this category thus improving our prevention strategies for this endemic disease. |
Published in: | |
| Journal | Malta Medical Journal |
| Volume | 15 Issue 1-2/suppl. 2003 |
| Pages | - |
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| Link to journal | |
| Key words | epidemiology, measles, prevalence, herd immunity |