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.
Contacting individuals in an existing study to request participation in a new study. Individuals in an existing study can be approached with an invitation to join further studies using locally-appropriate communications. this may be a text message (short message services) in areas where smart phones are not in current use. Call back facilities, such as ‘please call me’ text messages are often available where data and call time is limited by socioeconomic constraints.
