A holiday is a special day for religious or cultural reasons - such as Christmas, Easter, New Year's Eve, and your country's Independence Day. Some holidays are also official days off from work, and others are not.
A vacation is when you take multiple days off from work/school to relax and/or travel. However, American English speakers call this a vacation and British English speakers call this a holiday:
My parents are on vacation in Asia. (American English)
My parents are on holiday in Asia. (British English)
To stop the spread of HIV people simply need to give up promiscuous sex and drug use
Socioeconomic structures around the world constrain many peoples ability to make free choices regarding the behaviors that put them at risk for contracting HIV/AIDS. Economic insecurity, gender and racial inequalities, labor migration, and armed conflict all limit peoples ability to avoid exposure to the virus.