Sir--In their Seminar, A E Tattersfield and colleagues (Oct 26, p 1313)1
refer to the factors that can cause the immune system of children to
polarise towards a Th2 rather than a Th1 lymphocyte phenotype.
However, they do not mention any study exploring the incidence of
childhood asthma in relation to immunisation protocols. BCG and other
mycobacteria vaccines tend to facilitate this shift towards the Th1
phenotype, whereas most other commonly used vaccines tend to have the
opposite effect.
We investigated the possible link between early vaccinations and
asthma in two homogeneous populations of children. In the first group
(n=446), all children (mean age 8 years) had been breastfed for more
than a year and had received only breastmilk during the first 6
months.2 In the second group, all 274 children were pupils
of British Rudolf Steiner schools, and shared the same anthroposophic
lifestyle. In both groups we found a significant correlation between
pertussis vaccination and asthma.
However, we could not find the same correlation among the 210
pupils of a French Rudolf Steiner school that did not follow the same
immunisation programme as the British one. Most French pupils who had
received pertussis vaccination (and the vaccinations usually
associated with pertussis) had previously received BCG. We postulated
that diphtheria-tetanus-pertussis vaccination is a risk factor for
asthma if it is not preceded by BCG.3 By combining the data
from these three groups, we identified 214 children who had no
vaccination at all: four were diagnosed as having asthma.
We conclude that, in the future, epidemiological studies of asthma
should look at the immunisation status of the population under study.
*Michel Odent, Esther Culpin
Primal Health Research Centre, 72 Savernake Road, London NW3
2JR, UK (e-mail:modent@aol.com)
1 Tattersfield AE, Knox AJ, Britton JR, Hall IP. Asthma. Lancet 2002; 360: 1313-22. [Text]
2 Odent M, Culpin EE, Kimmel T. Pertussis vaccination and asthma:
is there a link? JAMA 1994; 272: 592-93. [PubMed]
3 Odent M. Future of BCG. Lancet 1999; 354: 2170-70. [Text]
