Correspondence

Immunology Series: Vaccines

N Engl J Med 2002; 346:864-866March 14, 2002

Article

To the Editor:

Dr. Ada's excellent review of vaccines and vaccination (Oct. 4 issue)1 was at once comprehensive and detailed. I must, however, take exception to his statement that “the recognition that [measles] immunity can wane after vaccination led to a two-dose vaccination schedule, which prevented the transmission of indigenous measles infections.” In fact, most would agree that most cases of measles in the vaccine era occurred in those who were susceptible to measles because of primary vaccine failure.2 Waning of immunity appeared to account for a very small number of cases of measles in patients who had received measles vaccine.3

Leslie L. Barton, M.D.
University of Arizona School of Medicine, Tucson, AZ 85724-5073
llb@peds.arizona.edu

3 References

1. 1

   Ada G. Vaccines and vaccination. N Engl J Med 2001;345:1042-1053
   Full Text | Web of Science | Medline

2. 2

   Poland GA, Jacobson RM, Thampy AM, et al. Measles reimmunization in children seronegative after initial immunization. JAMA 1997;277:1156-1158
   CrossRef | Web of Science | Medline

3. 3

   Markowitz LE, Preblud SR, Fine PE, Orenstein WA. Duration of live measles vaccine-induced immunity. Pediatr Infect Dis J 1990;9:101-110
   CrossRef | Web of Science | Medline

Author/Editor Response

Dr. Ada replies:

To the Editor: Finland was the first country to institute a two-dose vaccination schedule, an approach that prevented the transmission of measles in that country. The first dose was given at 14 to 18 months of age, and the second dose at 6 years of age, just before children entered school. Three reasons were given by Peltola et al. for the use of a second dose: “First, up to 5 percent of recipients were expected to have no response to all three vaccine components (primary failures). Second, a two-dose regimen was considered likely to reach more children than a single-dose schedule. Finally, the second dose was expected to boost declining antibody concentrations.”1 In the United States, the second dose of measles, mumps, and rubella vaccine is given at four to six years of age. By 1998, it had become very clear that more than 90 percent of children who had been immunized once maintained high antibody levels. Thus, an important function of the second dose was to boost the antibody titers of those with a poor response or no response to the first dose.

In response to numerous comments, I have revised Table 1Table 1The Status of Vaccines against Some Human Pathogens. of my article.

Gordon Ada, D.Sc.
Australian National University, ACT 2601 Canberra, Australia

1 References

1. 1

   Peltola H, Heinonen OP, Valle M, et al. The elimination of indigenous measles, mumps, and rubella from Finland by a 12-year, two-dose vaccination program. N Engl J Med 1994;331:1397-1402
   Full Text | Web of Science | Medline