Short-term PrEP for gay men going on holiday is feasible and acceptable


A short course of PrEP for gay and bisexual men who anticipate sexual risk behaviour while travelling is realistic, feasible and acceptable, US researchers report in the 15 August edition of the Journal of Acquired Immune Deficiency Syndromes. Adherence to daily PrEP was high among the 54 men who took part in this single-arm study.

PrEP (medication to prevent HIV infection) does not necessarily need to be taken long term. One alternative to daily PrEP is ‘event based’ dosing in which the medication is only taken for a few days before and after having sex. Another potential alternative might be using PrEP for discrete ‘seasons of risk’, such as travel away from home.

In a recent study, a quarter of gay and bisexual men reported condomless anal sex with a new partner while on holiday. Dr James Egan of the University of Pittsburgh describe holidays and vacations as a ‘liminal’ space that may involve fewer responsibilities, a desire for adventure, fewer inhibitions and more drug and alcohol use.



Having sex without condoms, which used to be called ‘unprotected’ or ‘unsafe’ sex. However, it is now recognised that PrEP and U=U are effective HIV prevention tools, without condoms being required. Nonethless, PrEP and U=U do not protect against other STIs. 


Passing gas from the digestive system out of the anus, or back passage (also called 'passing wind' or 'farting').


The feeling that one is about to vomit.


Abnormal bowel movements, characterised by loose, watery or frequent stools, three or more times a day.

event based

In relation to pre-exposure prophylaxis (PrEP), this dosing schedule involves taking PrEP just before and after having sex. It is an alternative to daily dosing that is only recommended for people having anal sex, not vaginal sex. A double dose of PrEP should be taken 2-24 hours before anticipated sex, and then, if sex happens, additional pills 24 hours and 48 hours after the double dose. In the event of sex on several days in a row, one pill should be taken each day until 48 hours after the last sexual intercourse.

Gay and bisexual men who reported condomless sex with two or more men on a recent vacation and who were planning another trip were recruited in Boston and Pittsburgh in 2016 and 2017. The 54 participants were mostly in their thirties and forties, well-educated and affluent.

The study involved:

  • A baseline visit at least two weeks before the planned trip, including screening for HIV.
  • An enrolment visit at least one week before the trip, including a 30-minute adherence intervention and provision of oral PrEP.
  • A ‘conservative’ recommendation to take PrEP daily for seven days before the trip, throughout, and for seven days afterwards.
  • A post-trip visit within three days of return, which included assessments of adherence, which 48 men attended.
  • Follow-up visit after three months, including HIV testing, which 42 men attended.

On their return, three-quarters of men reported condomless sex while they were away and almost a third reported some recreational drug use.

Blood tests showed that almost all men had drug levels suggesting that had taken PrEP daily (91.5%) or at least four times in the previous week (93.6%), despite concerns that holidays may be a challenging time to adhere to a medication. Self-reported adherence was similarly high.

Just under a third reported some side effects, most commonly diarrhoea, flatulence or nausea, but nobody stopped PrEP early.

Nobody acquired HIV while in the study.

Of note, 71% of participants said they were interested in remaining on PrEP after the end of their holiday. The authors comment that using PrEP episodically may provide some men with the opportunity to try PrEP out and get comfortable with it, before integrating it into their daily life.


Egan JE et al. Feasibility of Short-Term PrEP Uptake for Men Who Have Sex With Men With Episodic Periods of Increased HIV Risk. Journal of Acquired Immune Deficiency Syndromes, 84: 508-513, 2020.

doi: 10.1097/QAI.0000000000002382