don't know of this is helpful, but believe the HIPPA laws in U.S. regarding confidentiality prohibit email transmissions as too easy to intercept -   transmission of psychotherapy reports okay to use FAX

It is very possible that I did not correctly understand the question so I have to beg pardon if my following words are falling the real signification of the question. If it would means the possibility to acquire  informations to be used in a research or in a medical anamnestic investigation by a third person, even he/she could have a very intimate relationship as in case of a sexual partner, where in any case the full reciprocal knowledge is not necessarily so sure, the received informations always deal reported data, whose exactness would depend on  a real true communication to the referring partner and on his/her real full understanding of what communicated, and consequently informations of doubtful usefulness in the two above hypothesized conditions. With all my  humble apologies in case of my rough misunderstanding.   

Kabasele, it's impossible to guarantee that the contents of an SMS message or an email will be seen only by the intended recipient. It's quite common for couples to share their phones and email accounts, and in an unequal relationship a message might be viewed by the partner without the patent's consent.

A better option might be to send a message asking the patient to telephone the clinic, but using an innocuous 'coded' form of words - one that provides no information to a third party, and which has been agreed between patient and clinician at the time of the initial visit.

Thanx, Chris.  Agree. 

 With regard to Giancarlo answer, my understanding of the research project is such that after an STI diagnosis, the partner of the participant would be notified through an sms message. My question is related to the content of this sms message. Would the partner be requested, for example, to call the health facility as suggested by Chris Showell, or the investigators would inform him (her) about the sti diagnosis in this sms message? At the time the sms is sent to the partner, is the latter part of the study, or will (he) she become a study participants if he (she) responds to the sms and accept to enroll in the study? There are several ethical issues related to the disclosure of this information. That is why I asked this question. 

Dear Kabasele, thank you for explanation. The possibility of the disclosure of an important information concerning a very important aspect of the personal health I think that firstly could depend on the local laws about this matter. If the law allows this possibility, I think that the disclosure could or should depend on the permission of the interested  person, particularly if the disclosure should be released for study purpose and not only for health interest of the other person. Always hoping to have now correctly understood

Yes, Giancarlo, your answer adresses my question. The participant as you say, can authorise the disclosure of his medical condition to a specific third person (e.g., closer relatives, insurance) in South Africa, but it should be done in a way that ensure confidentiality and preserve the medical secrecy. Relatives are usually informed during a confidential face to face with the treating health care professional. 

Dear Kabasele, thank you for your reply, that let me know the law conditions to operate in this field in South Africa, Taking into account the particular interest and  delicacy of this topic it could be very interesting to know the possible differences in dealing this matter in the different Countries. For what concerning Italy it looks to me similar to what you described in South  Africa.