A study in Israel found Pfizer/BioNTech's COVID-19 vaccine to be less effective on the variant found in South Africa.
However, the variant's occurrence in the country is low, and the research has also not been peer-reviewed.
The study, released on Saturday, compared almost 400 people who tested positive at least two weeks after receiving one or two doses of the vaccine against the same number who had tested positive but were unvaccinated.
It also matched age and gender, among other characteristics.
South Africa's variant was found to make up 1% of all cases in the study, according to Tel Aviv University, and the country's largest healthcare provider, Clalit.
They found that the variant was eight times more prevalent in patients who had received two doses of the vaccine, compared to those who were unvaccinated.
According to Tel Aviv University professor Adi Stern, the data suggests that the South African variant is able to break through the vaccine's protection to some extent.
The researchers cautioned that the data was not intended to deduce overall vaccine effectiveness against other variants, since it only looked at people who had already tested positive for COVID-19, instead of overall infection rates.
Pfizer and BioNTech could not be immediately reached for comment outside business hours.