 |
 |
 |
 |
|
|
|
|
 |
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|||||||||||
|
|||||||||||||||||
Perspectives
Marc Lipsitch
Emory University, Atlanta, Georgia, USA
 |
| Back to article Figure 1. The structure of the mathematical model described in the text and in greater detail (30). |
 |
| Back to article Figure 2. Carriage of three serotypes of Haemophilus influenzae in children vaccinated against serotype b (black bars) and in controls (white bars) (14). Error bars indicate 95% confidence interval (binomial approximation). Shaded bars show the maximum carriage of serotypes e and f in vaccine recipients that could result from replacement in a population where only a small proportion of susceptibles are vaccinated (as in the study). Striped bars show the equivalent figures in a hypothetical study in which virtually all susceptibles were vaccinated. |
 |
| Back to article Figure 3. Two hypotheses explain the observation of higher rates of carriage of nonvaccine serotypes in vaccine recipients than in controls. Large circles represent plated samples from controls (top) andvaccine recipients (bottom). The left side shows true serotype replacement; here a control carries vaccine types (white colonies), while a vaccine recipient does not, and (possibly as a result of decreased competition) now carries only nonvaccine types (black colonies). The right side shows the unmasking phenomenon, which is an artifact of sampling. Here, both vaccinees and controls carry nonvaccine types, but because only one colony is sampled in each, the vaccinee does not appear to carry nonvaccine types. |
Home | Top of Page | Current Issue | Expedited | Upcoming Issue | Past Issue | EID Search | Contact Us CDC Home | Search | Health Topics A-Z This page last reviewed July 1, 1999 Emerging Infectious Diseases Journal |