Brazilian President Jair Bolsanaro has launched a crusade against the governor of Brazil's largest state, São Paulo, over a Chinese-made vaccine that ultimately could help the country combat the pandemic that's infected 5.3 million Brazilians and killed 157,000.

“The Brazilian people will not be anyone’s guinea pig...That is why I have decided not to purchase this vaccine,” Bolsonaro wrote on his Facebook page on October 21, refuting reports that the Health Ministry would purchase 46 million doses of the vaccine that São Paulo's governor recently called the “most promising.”

The vaccine in question, CoronaVac, is being developed by Chinese pharmaceutical company Sinovac. In railing against CoronaVac, Bolsonaro cited its country of "origin" specifically. The episode is fueling fears globally that geopolitics—not science—will shape mass immunization campaigns as COVID-19 vaccines start to gain market approval.

“Safest, most promising”

With the third-highest number of coronavirus cases in the world, Brazil has become the ultimate testing ground for coronavirus vaccines. Companies behind five of the ten vaccines currently undergoing late-stage phase III trials are testing their candidates in the South American country because they need a high rate of infection to determine if their experimental doses work. Early last week, Brazilian officials signaled their favorite: Sinovac's candidate, CoronaVac.

“The first results of the clinical study conducted in Brazil prove that among all the vaccines tested in the country, CoronaVac is the safest, the one with the best and most promising rates,” said João Doria, the governor of São Paulo.

Doria—a vocal Bolsonaro critic—negotiated a partnership between Sinovac and the Butantan Institute, a Brazilian vaccine research center, to develop and test CoronaVac in Brazil.

The day after Doria declared CoronaVac the “most promising,” Health Minister Eduardo Pazuello announced that the federal government would purchase 46 million doses of the vaccine from the Butantan Institute as part of a national immunization program. The deal is dependent on the vaccine getting approval from federal drug regulator, Anvisa.

The next day, Bolsonaro intervened.

Campaign against CoronaVac

Bolsonaro derided CoronaVac as “João Doria’s Chinese vaccine,” in response to a Facebook question about it, and said “for sure we will not buy the Chinese vaccine.”

Later the same day, the Health Ministry said in a statement that reports of the 46 million dose purchase were a “misinterpretation” of Pazuello’s remarks. According to the statement, the ministry had simply signed a “non-binding memorandum of understanding” with the Butantan Institute to buy the vaccines.

Meanwhile, Bolsonaro has continued his anti-CoronaVac campaign.

On October 21 the president posted a video of himself alongside Pazuello. The health minister, who currently has the coronavirus, seemed to comply with the president’s demand to cancel the purchase, saying "the boss commands and we obey."

Later the same day, Bolsonaro told a radio show that Brazil “won’t buy [a vaccine] from China” .

Then on October 24, Anvisa, Brazil's health regulator, approved the import of 6 million doses of CoronaVac for phase III trials. Doria said discontinuing late-stage testing of the vaccine would be "criminal." He found an ally in Rodrigo Maia, the speaker of Brazil's lower legislative house, who urged Bolsonaro to reconsider his objection to the vaccine.

Political game

Bolsonaro has had a mercurial relationship with China. He started his term as a brash China hawk—dubbed the 'Tropical Trump'—but he warmed to China as a trade partner during the pandemic, as exports to China have been an economic lifeline for Brazil.

Recently, the Brazilian president seems to have turned more towards the U.S., pledging support for Trump’s re-election and reportedly considering a ban on Huawei Technologies, the Chinese telecom manufacturer that the Trump administration considers a security threat.

Bolsonaro’s outright rejection of a Chinese vaccine—despite it reportedly being the safest option to date—appears to be another political move. His government is instead throwing support behind a vaccine developed by the U.K.-based AstraZeneca.

The Brazilian government has invested over $350 million in the British vaccine, and AstraZeneca’s doses are included in the national immunization plan.

Bolsonaro has accused Doria of playing a “political game” by backing the Sinovac vaccine.

Doria has hit back, claiming that Sinovac's vaccine is "Brazil's vaccine" because the Butantan Institute is helping develop it. He warned governments against "evaluat[ing] vaccines on political or ideological criteria.”

Brazil’s failure

Doria is not the only Brazilian governor affronted by Bolsonaro’s rhetoric. Maranhao state Governor Flavio Dino has said there is “general outrage” among state leaders.

Many see the president's refusal to consider a promising vaccine as only the latest federal misstep.

Brazil recorded its first case of coronavirus on Feb. 25, one day before the U.S. detected its first instance of human-to-human transmission. Since then, Brazil has accumulated one of the highest tallies of COVID-19 cases in the world.

On October 20, a group of Brazilian scientists condemned Brazil’s response to the pandemic in The Lancet, a highly-respected U.S. medical journal, arguing that Brazil’s federal government failed at every stage to implement any coordinated plans to combat the virus.

“The conclusion that Brazil has shown one of the worst responses to the pandemic is unequivocal,” the researchers wrote.

For its part, China’s Ministry of Foreign Affairs has stressed that China remains committed to working with Brazil in developing a vaccine.

“China and Brazil have been cooperating amid COVID-19,” foreign ministry spokesperson Zhao Lijian said at a press conference on October 22. “With the phase III of vaccine clinical trials jointly launched by both sides smoothly progressing in Brazil. We believe our cooperation will help people in China, Brazil and across the world to defeat the pandemic.”

Brazil's internal debate over the Chinese vaccine may prove a microcosm of how the global vaccine race plays out in months to come.