In a follow-up study conducted one year after a previous report, we found that 7.8% of 126 patients with critical illness or injury were infected with the human immunodeficiency virus (HIV-1) in 1987 as compared with 3.0% of 203 similar patients in 1986. In the earlier study all patients with infection (six) were confined to a narrow age range (25 to 34 years old) and were trauma presentations. However, in the follow-up study, infections were found in all age groups under 45 years of age (nine) as well as in 3.4% of patients with nontrauma presentations. Infection rates among patients between the ages of 25 and 34 presenting with penetrating trauma remained over 18% during both study periods. While emergency health care providers may have inadvertently interpreted the results of the first study as indicating that the need for infection control precautions could be restricted to young victims of trauma, the follow-up study clearly indicates that appropriate protective measures must be taken on all patients requiring resuscitative measures regardless of age or clinical presentation, particularly in emergency facilities within similar locations.