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.
Estimated influenza virus attributable fraction (AF) and AF trends across age groups among inpatients with severe acute respiratory illness, Klerksdorp and Pietermaritzburg, South Africa, May 2012–April 2016. A) HIV-infected patients (AF trends estimated using model 1, a linear model). B) HIV-uninfected patients (AF trends estimated using model 2, a quadratic model).
