This means that their immune system has been able to naturally suppress their HIV infection to the extent that the virus is not detectable in their bloodstream.
They are known to be infected as they have HIV antibodies circulating in their blood, even though they have never been on any anti-retroviral therapy (ART).
Speaking to The Star via videocall, study co-author Dr Mary Rodgers said: "This study where we found a large number of HIV controllers was really unexpected for us.
"And when we saw the sheer numbers of people who met this category of an HIV controller – who can control HIV naturally without taking any medication – we found this to be really groundbreaking."
She said that this discovery gives new hope for potential cures and vaccines to be unlocked for this chronic infection that can eventually develop into the fatal AIDS (Acquired Immunodeficiency Syndrome).
"To me, the million-dollar question is: what makes these people unique? How are they able to accomplish this naturally?
"Perhaps there is something new and different about the immune response of these particular patients, and that's certainly a starting point," she said.
The study, published online today (March 2, 2021) in the journal EBioMedicine, reported that 11% of 10,457 people, who provided blood samples over the period of 2017-2019, were HIV positive.
The study authors noted that this percentage alone was higher than the previous estimate of HIV in the Congo, which was 2.86%.
Within the HIV-positive group, 2.7-4.3% were found to be natural elite controllers of the virus.
On average, studies worldwide have found the frequency of HIV elite controllers to be less than 1%.
"This would make the Congolese numbers five to 10 times more," said Dr Rodgers, who manages American medical devices and healthcare company Abbott's Global Viral Surveillance Programme, which provided the data for the study.
She noted that this represents thousands of potential HIV elite controllers in the Congo who can now be studied to determine the trends and similarities between them that enable them to fight off the virus.
Having found a 2017 study from Cameroon in the Virology Journal that reported 2.95% of their HIV positive participants were elite controllers of the infection, the study authors also analysed previous data from the same country collected by the Abbott Global Viral Surveillance Program from 2004 to 2017.
They reported that estimations based on this data suggest that 2.5-5.8% of Cameroonians might be HIV elite controllers as well.
The Democratic Republic of Congo and Cameroon are neighbouring countries.
Dr Rodgers noted that with HIV having its origins in that part of the world, it would not be surprising that the ability to control HIV may also come from there.