ABSTRACT
Most of the facts regarding measles aerosol vaccination have been quite thoroughly dealt with in
the book by S. Plotkin, Mass Vaccination: Global Aspects—Progress and Obstacles (2006 Ed) [1]. However,
there are some aspects mentioned there that should perhaps have been emphasized more
strongly and others that have emerged as relevant issues since then. We shall start with the quite
important point that in the Sabin et al. [2] first study made in Monterrey, N. L., México [3], antibody
reaction for recipients of respiratory-route Edmonston-Zagreb vaccines was not fully developed
(100%) until six months after aerosol inhalation. At six weeks, only 90% had increased blood
levels of antibody, a fact for which there is no easy explanation, but one which should be considered
when dealing with serologic evaluation of measles vaccines given by aerosol in which shortterm
results less than encouraging. Results of the second study performed by Sabin et al. in Monterrey
[2] establish that the percentage of sero-responses is directly dose-dependent. In turn, the
dose itself depends on at least three facts: 1) concentration of virus in the vaccine used; 2) kind of
nebulizer used; and 3) time of exposure. Another point to be stressed is that the vaccine used in
the first trials [1]-[3], as well in the aerosol mass vaccination in México, though originally the Ickic
strain attenuated in HDP, was also grown for final harvesting in HDP (MRC-5), whereas current
Edmonston-Zagreb vaccines are obtained by final culture in chick embryo fibroblasts that provide
1 log more final product, more beneficial from an economic point of view, but not for adaptation to
human tissues. A crucial consideration in aerosol measles mass campaigns is the lack of electricity/
energy supply, particularly in rural communities. To deal with these issues, a rudimentary assembly
was utilized to produce the aerosol for mass vaccinations performed during the serious
Mexican epidemic of 1990-1991: a tire pump connected to a Clay-Adams nebulizer. As this equipment
works only with direct current, a car battery was used to supply sufficient energy to vaccinate
thousands of children.