Smallpox Vaccination: Abo and Rhesus Blood Groups.

The hypothesis has been advanced (Pettenkofer and Bickerich, I96o) that vaccinia virus and, by implication, variola virus contain antigenic properties similar to human blood group A substance. Vogel, Pettenkofer, and Helmbold (I960) assert that possession by variola virus of a material serologically resembling human blood group A substance may have been responsible, in part, for determining the present-day global distribution of the human ABO blood groups. Pettenkofer, Stoss, Helmbold, and Vogel (I962) claim that, in smallpox infection, persons with blood groups B or 0, in whom anti-A normally occurs, have an immunological advantage over persons of blood groups A and, presumably, AB who lack this antibody. In support of their work these authors report that of I03 Germans with severe postvaccination reactions (more than go% encephalitis) a significantly higher proportion belonged to blood groups A and AB; moreover, in India and Pakistan, among 358 subjects with severe smallpox scars a similar excess of blood groups A and AB was demonstrated. If the above hypothesis is correct, and recent experimental work (Harris, Harrison, and Rondle, I963) suggests that it is not, one would expect, among a group of individuals vaccinated against smallpox that: (i) persons of blood groups B or 0, who possess anti-A substance, would be more likely to resist the procedure, and present an unsuccessful vaccination, than groups A or AB; (ii) persons of blood groups A or AB, who do not possess anti-A in their serum, would have a more severe clinical response, and might be expected to produce a larger lesion following successful vaccination, and to have a greater scar area from previous vaccination than persons of blood groups B or 0. The present study is concerned with the distribution of the ABO and Rhesus blood groups among a number of university students vaccinated against smallpox. The materials and methods, reading of results, and observations on clinical reaction have already been outlined (Bourke and Clarke, I963, 1964).