Abstract
OBJECTIVE: To examine the factors associated with measles vaccine effectiveness and the effect of two doses of vaccine on measles susceptibility during an outbreak. DESIGN: Retrospective cohort study. SETTING: A secondary school in the City of Toronto. SUBJECTS: The entire school population (1135 students 14 to 21 years of age). MAIN OUTCOME MEASURES: Risk of measles during an outbreak associated with age at first measles vaccination, length of time since vaccination, vaccination before 1980 and whether date of vaccination was estimated; vaccine efficacy of one dose versus two doses. RESULTS: Eighty-seven laboratory-confirmed or clinically confirmed cases of measles were identified (for an attack rate of 7.7%). The measles vaccination rate was 94.2%, and 10% of the students had received two doses of measles vaccine before the outbreak. Among those who had received only one dose of vaccine, vaccination at less than 15 months of age was associated with vaccine failure (relative risk 3.62, 95% confidence interval 2.32 to 5.66). There was no increased risk of vaccine failure associated with length of time since vaccination once the relative risk was adjusted for age at vaccination in a stratified analysis. Vaccination before 1980 and an estimated date of vaccination were not associated with increased risk of vaccine failure. Administration of a second dose of vaccine during the outbreak was not protective. Two doses of vaccine given before the outbreak conferred significant protection, and the relative risk of failure after one dose versus two doses was 5.0 (95% confidence interval 1.25 to 20.15). Of the 87 cases, 76 (87%) could have been prevented had all the students received two doses of measles vaccine before the outbreak, with the first at 12 months of age or later. CONCLUSIONS: Delayed primary measles vaccination (at 15 months of age or later) significantly reduced measles risk at later ages. However, revising the timing of the current 12-month dose would leave children vulnerable during a period in which there is increased risk of complications. The findings support a population-based two-dose measles vaccination strategy for optimal measles control and eventual disease elimination.
Full text
PDF






Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Brunell P. A., Weigle K., Murphy M. D., Shehab Z., Cobb E. Antibody response following measles-mumps-rubella vaccine under conditions of customary use. JAMA. 1983 Sep 16;250(11):1409–1412. [PubMed] [Google Scholar]
- Katz S. L., Gellin B. G. Measles vaccine: do we need new vaccines or new programs? Science. 1994 Sep 2;265(5177):1391–1392. doi: 10.1126/science.8073281. [DOI] [PubMed] [Google Scholar]
- Marks J. S., Hayden G. F., Orenstein W. A. Methodologic issues in the evaluation of vaccine effectiveness: measles vaccine at 12 vs. 15 months. Am J Epidemiol. 1982 Sep;116(3):510–523. doi: 10.1093/oxfordjournals.aje.a113435. [DOI] [PubMed] [Google Scholar]
- Mast E. E., Berg J. L., Hanrahan L. P., Wassell J. T., Davis J. P. Risk factors for measles in a previously vaccinated population and cost-effectiveness of revaccination strategies. JAMA. 1990 Nov 21;264(19):2529–2533. [PubMed] [Google Scholar]
- Matson D. O., Byington C., Canfield M., Albrecht P., Feigin R. D. Investigation of a measles outbreak in a fully vaccinated school population including serum studies before and after revaccination. Pediatr Infect Dis J. 1993 Apr;12(4):292–299. doi: 10.1097/00006454-199304000-00007. [DOI] [PubMed] [Google Scholar]
- Orenstein W. A., Bernier R. H., Hinman A. R. Assessing vaccine efficacy in the field. Further observations. Epidemiol Rev. 1988;10:212–241. doi: 10.1093/oxfordjournals.epirev.a036023. [DOI] [PubMed] [Google Scholar]
- Orenstein W. A., Markowitz L., Preblud S. R., Hinman A. R., Tomasi A., Bart K. J. Appropriate age for measles vaccination in the United States. Dev Biol Stand. 1986;65:13–21. [PubMed] [Google Scholar]
- Osterman J. W., Melnychuk D. Revaccination of children during school-based measles outbreaks: potential impact of a new policy recommendation. CMAJ. 1992 Mar 15;146(6):929–936. [PMC free article] [PubMed] [Google Scholar]
- Peltola H., Heinonen O. P., Valle M., Paunio M., Virtanen M., Karanko V., Cantell K. The elimination of indigenous measles, mumps, and rubella from Finland by a 12-year, two-dose vaccination program. N Engl J Med. 1994 Nov 24;331(21):1397–1402. doi: 10.1056/NEJM199411243312101. [DOI] [PubMed] [Google Scholar]
- Poland G. A., Jacobson R. M. Failure to reach the goal of measles elimination. Apparent paradox of measles infections in immunized persons. Arch Intern Med. 1994 Aug 22;154(16):1815–1820. [PubMed] [Google Scholar]
- Shepard D. S. Economic analysis of investment priorities for measles control. J Infect Dis. 1994 Nov;170 (Suppl 1):S56–S62. doi: 10.1093/infdis/170.supplement_1.s56. [DOI] [PubMed] [Google Scholar]
- Tulchinsky T. H., Ginsberg G. M., Abed Y., Angeles M. T., Akukwe C., Bonn J. Measles control in developing and developed countries: the case for a two-dose policy. Bull World Health Organ. 1993;71(1):93–103. [PMC free article] [PubMed] [Google Scholar]
- Yuan L. Measles outbreak in 31 schools: risk factors for vaccine failure and evaluation of a selective revaccination strategy. CMAJ. 1994 Apr 1;150(7):1093–1098. [PMC free article] [PubMed] [Google Scholar]