In this Marc 4, 2021, file photo, a nurse prepares the AstraZeneca COVID-19 vaccine at Al-Nozha Hospital in Cairo, Egypt. Credit: Nariman El-Mofty / AP

The more infectious nature of the delta mutation of the coronavirus has seen it almost completely displace the beta variant in South Africa, the discovery of which led to widespread travel bans.

A study, released by two South African genomics institutes Thursday, showed that the delta variant, first identified in India, drove a third wave of infections in the country. Excess death data show that about a quarter of million people may have died from the virus.

“The dominance of delta was consistently observed through increased genomic surveillance during the third wave, with the detection of beta drastically decreasing to almost none in the last weeks,” the scientists said in the report.

The study will add fuel to a political standoff between South Africa and the U.K., which this month kept the African nation on its so-called red list that imposes costly and time consuming restrictions on travel between the countries. The U.K. is the biggest source of foreign tourists for South Africa.

The U.K. cited the beta variant as a reason for its decision, leading to accusations from scientists and politicians that it was failing to follow scientific data.

The scientists from the the centers at Stellenbosch University and the University of KwaZulu-Natal estimated that the delta variant is 46 percent more transmissible than beta.

“The degree to which the growth advantage of delta is mediated by inherent increased transmissibility and/or immune evasion cannot be determined,” the scientists said.

Story by Antony Sguazzin.