The health insurer Aetna is facing criticism for revealing the HIV status of potentially thousands of customers after it sent out a mailer in which information about ordering prescription HIV drugs was clearly visible through the envelope's clear window.

For example, in a letter sent to a customer in Brooklyn, N.Y., the window revealed considerably more than the address. It also showed the beginning of a letter advising the customer about options "when filling prescriptions for HIV Medic ... "