Pfizer and BioNTech offered to supply South Africa with their Covid-19 vaccine at a discounted $10 a dose, according to a person familiar with the talks, yet the president’s office still described the cost as prohibitive.

The price was worked out according to South Africa’s status as a middle-income nation and is about half of what the drugmakers are charging in the US, the person said, asking not to be identified as the information hasn’t been made public.

The fact that the companies are running a vaccine trial in the country was also taken into consideration, the person said.

A spokeswoman for South Africa’s Department of Health said the ministry can’t comment on the pricing as a deal is yet to be concluded. Representatives for Pfizer and BioNTech in Europe didn’t immediately respond to a request for comment.

South Africa’s government is coming under mounting pressure from its labor-union allies, opposition parties and medical professionals over its failure to secure any bilateral vaccine-supply agreements with pharmaceutical companies. While at least 29 countries have already begun inoculating their populations, South Africa only expects to start getting shots for about 10% of its population in the second quarter. That deal has been arranged through the Covax initiative, which is designed to ensure poorer countries can secure access.

The country has had 1.1-million confirmed cases of Covid-19 and is approaching 30,000 deaths, the most of any African nation.

In a statement sent to Bloomberg News on Sunday, the South African presidency said Pfizer was one of at least three companies the government is in negotiations with for the supply of shots. It also said Pfizer has offered 50-million doses for health workers across Africa that could arrive between March and the end of the year.

"Factors that will be taken into account include the suitability for the South African context," the presidency said, noting that the Pfizer vaccine requires ultra-cold storage.

"The cost is also prohibitive."

Tyrone Seale, acting spokesman for President Cyril Ramaphosa, declined to comment further.