When he was diagnosed 10 years ago, Kovacic promptly informed the hospital where he worked as a nurse.
"They kept transferring me from post to post. Finally, when they wanted me to work in the hospital archives, a woman working there threatened to resign if I came," he said.
"I realised that I had nothing to do there," 43-year-old Kovacic said. Instead he turned to disability benefits for the chronically ill, which he began receiving six years ago.
He is now an official of USOP, an umbrella group of Serbian organisations helping people with HIV/Aids.
"Because of stigma and discrimination, people sometimes do not tell anyone that they are HIV-positive," Kovacic said. "Knowing what I know now I am not sure I would do so again."
Although the overall infection rate is low in the Balkans region, the prevalence of HIV/Aids among youths is increasing rapidly, according to non-governmental organisations.
Officially the registered number of HIV-positive people is only 65 in Bosnia and 103 in Montenegro, but experts say the real figures could be at least 10 times higher.
In Montenegro, a tiny Adriatic state with only 660,000 inhabitants, the number of those infected has increased by 33 percent from 2005 to 2009, official figures show.
"The pervasive stigma and discrimination by health care providers and society at large against high-risk populations — and self-imposed isolation of people living with HIV and Aids — further fuels the growth of the epidemic" in the western Balkans, a health NGO, Fondation PH Suisse, said in a 2010 report.
While patients have no trouble getting treatment and most countries of the former Yugoslavia often pay for medication, those with HIV/Aids may not get other treatment such as dental work because many health workers fear infection.
Infected children or children of infected parents are also not welcome in schools.
Local NGOs like USOP are setting up a regional body to combat the prejudice. The first step will be a special conference in April year dedicated to HIV-infected people and their way of life where they will officially launch the initiative to start a regional association.
"We realised, while touring the region, that our problems were almost identical," said Vladimir Antic of USOP.
For Tomislav Beganovic of Croatia's Association for HIV and Hepatitis Patients, "discrimination ... is born of ignorance, so we need to raise awareness."
The lack of knowledge about how the virus is transmitted often leads to isolation and discrimination against people carrying the virus.
"They are often excluded from a society, lose their job, they are deprived of their basic human rights and education," said Tatjana Preradovic-Sjenica, a psychologist with Viktorija, a Bosnian Serb non-government group in Banja Luka.
The prejudices also keep many from getting tested, especially in Bosnia and Montenegro. Even taking a test would mean effectively admitting to having behaved in a way that could lead to infection — that is, through homosexual sex or illegal drug use.
"We try to motivate people to take a test," said Preradovic-Sjenica in Bosnia.
"Fear of being identified or what the results of the test could be leads many people to conclude it's better not to know," she said, even though the tests can be taken anonymously and are free, as is treatment for infected patients.
In the Balkans region, where traditional family values run deep, people living with HIV are often shunned even by their own relatives.
Kovacic noted: "We do not have any place to house people rejected by their families. They live in hospitals until they die."