Figure 1.

Diagnostic vaccination according to the AAAAI guidelines. (A) Flow of events. The preexisting immunity (natural immunity), represented by the levels of multiple (undefined number) serotype-specific antibodies, is determined at an undefined time-point before vaccination (t = ?). Later, PPV is administered (t = 0). The immunity after PPV is assayed four to eight weeks later by quantifying the same serotype-specific antibodies. (B) Model showing the theoretical probability of achieving adequate immunity (y-axis, left) according to the AAAAI guidelines (i.e., the probability of at least 70% of serotype-specific antibodies reaching levels of at least 1.3 mg/L) as a function of the number (x-axis) of tested serotype-specific antibodies. The colored curves represent different probabilities of an individual antibody being classified as ‘protective’ (i.e., a level of at least 1.3 mg/L). The probability of achieving ‘adequate immunity’ follows the binomial distribution, under the simplifying assumption that the individual serotype-specific antibodies in a given panel have equal likelihoods of being at the ‘protective’ level (although this will rarely be the case, the simplification nonetheless serves to illustrate the underlying problem).