Relationship between occurrence of Guillain-Barre syndrome and mass campaign of measles and rubella immunization in Iranian 5-14 years old children.

BACKGROUND: Case reports and epidemiologic studies have reported a relation between different vaccines including measles, rubella, mumps and Guillain-Barre syndrome (GBS). In this study we investigated relation between receiving measles and/or rubella vaccines and occurrence of GBS after national immunization campaign in 2003 in Iran.

MATERIALS AND METHODS: We used the national surveillance system for acute flaccid paralysis from the beginning of 2002 to the end of 2004 and studied the incidence of GBS disease among 5-14-year-old children. The 3-year time span of the study was divided into fifteen 10 weeks intervals and the number of reported and confirmed GBS case reports in each time period was analyzed supposing their distribution was according to Poisson distribution.

RESULTS: From 2002 through 2004 there were 370 patients confirmed GBS case reports among persons 5-14 years of age. The annual incidence in this age group remained relatively constant over the 3-year period and ranged from 0.65 per 100,000 population in 2004 to 0.76 in 2003. The estimated average annual incidence of GBS in persons <15 years of age was 1/100,000 (CI 95%: 0.88-1.13), and 0.7/100,000 in persons 5-14 years of age (CI 95%: 0.58-0.83). No obvious seasonal pattern in GBS occurrence was observed. The mean number of GBS patients during each 10 week study interval was 23.8. Twenty-five patients with GBS were reported in the time period which coincided with national immunization campaign. The probability of occurring >or=25 cases of GBS in that time period according to Poison distribution with expected case numbers of 23-8 is equal to 0.43 (p=0.43).

CONCLUSION: The yearly incidence rate of GBS in this study was similar to other studies. According to our results, there was no increase in GBS Incidence in the 4 weeks national Immunization campaign and 6 weeks after it in comparison to other 10 weeks periods before or after this time period.