| exp(−λ(t)) | - where more than 90 days have passed since an infection by any serotype and the individual has not previously been infected by serotype s |
| 0 | - otherwise, including periods when the individual is not part of the study |
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.