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.
Risk of missed presentation by time period stratified by clinical and epidemiological risk factors. * Breslow-Day test of homogeneity of variance: P < 0.05 suggesting significant heterogeneity within the strata. † Not calculable due to small numbers. Transmission risks of IVDU, partner HIV positive, recipients of blood products/organs or dialysis patients were not calculated due to small numbers.
