Of all the developing countries testing China’s Covid-19 vaccines, few are friendlier to Beijing than Pakistan. In the years leading up to the pandemic, China financed nearly $70 billion across the South Asian nation on roads, railways and power stations, and Pakistan now has two Chinese clinical trials underway, with even senior government officials being inoculated.

Yet interviews with people in Karachi, the nation’s biggest city — as well as in other developing nations from Indonesia to Brazil, together with surveys and official comments — show that China has failed to assure the millions of people who may have to rely on its vaccines.

“I won’t take it,” said Farman Ali Shah, a motorcycle driver in Karachi for local ride-hailing app Bykea, as local shops closed early ahead of an 8 p.m. virus-induced curfew. “I don’t trust it.”

That mistrust, and the reliance of dozens of poorer nations on China to inoculate their populations could set the stage for a major global political headache if citizens offered the Chinese vaccine feel they are being given an inferior product.

China’s vaccines were meant to score a clear diplomatic win for Beijing, shoring up ties with dozens of poorer nations amid an anticipated shortage of Western-developed shots. But there has been little information about how the Chinese versions have fared in final-stage clinical trials, with just the United Arab Emirates and China itself endorsing the vaccines for emergency use so far. Meanwhile, some U.S. and European companies have published data on the safety and efficacy of their shots and started to deploy them.

That uncertainty presents another roadblock in China’s efforts to extend its political influence across Asia, Africa and South America. Through its seven-year-old Belt and Road Initiative, Beijing spent billions on loans and projects and cultivated local elites to buttress its political and economic power — efforts that have often backfired because of poor management and heavy-handed implementation. The mistrust was compounded by China’s exports early in the pandemic of subpar tests and personal protective equipment.

“China has a great opportunity to do vaccine diplomacy and distribute a life-saving product,” said Jorge Guajardo, a senior director for McLarty Associates, who was Mexico’s ambassador to China for six years. “In my experience, every time they’ve engaged in diplomacy, they screw it up — they manage to upset the countries on the receiving end of their aid.”

Missteps could undermine President Xi Jinping’s claims that China’s ruling Communist Party has handled the virus better than western democracies. China, which saw the first known cases of Covid-19 a year ago, used its authoritarian system to virtually eliminate the virus, mass testing millions of people when cases emerged, shutting its borders and locking down parts of the country to snuff out infections. That approach has seen China’s economy begin to recover even as countries such as the U.S. and U.K. struggle to control outbreaks.

Bolstered by its virus success, Beijing sparred with the U.S., U.K. and Australia over everything from the origins of the virus to crackdowns in Hong Kong and Xinjiang. The pain of the pandemic also hardened the stance of the U.S. and China in wider economic disputes, including American efforts to stop countries from adopting the next-generation communications technology of China’s Huawei Technologies Co.

“The key thing I am looking out for is if they come in with offers for a vaccine in exchange for a countries’ commitment to using Huawei 5G telecommunication lines, or to allowing China to invest in key sectors,” said Guajardo. “Given that they have a history of this behavior, it wouldn’t surprise me if they did it again.”

China has made a global effort to reassure governments and populations about the efficacy and safety of its vaccines. In October, a group of ambassadors and diplomats representing 50 African countries toured a Sinopharm Group Co. facility amid a publicity blitz touting China’s promise to deliver vaccines to Africa. “When the coronavirus vaccine completes research and is put into use, we are willing to prioritize benefiting African countries,” said Liu Jingzhen, chairman of Sinopharm.

In response to questions from Bloomberg, China’s Foreign Ministry said Chinese companies developing vaccines strictly comply with the law and clinical trials in the first two phases showed the shots were safe and effective. The Chinese government has administered more than one million emergency vaccine doses since July, it said, and “we have haven’t found any serious adverse reactions.”

“China has always attached great importance to the safety and efficacy of vaccines,” the Foreign Ministry said in the statement on Dec. 22.

On China’s side is mathematics. The challenge of manufacturing, distributing and administering billions of doses means many developing nations may have little choice but to use Chinese vaccines for at least part of their populations. Many don’t have enough facilities to store Pfizer Inc.’s shot, which needs to be stored at -70 degree Celsius.

China has also agreed to supply its vaccine to Covax, a World Health Organization-backed effort to provide a coronavirus vaccine to developing nations. AstraZeneca Plc, the other main Covax partner, is still waiting to gain approval. Britain’s drug regulator could clear its shot for use as early as this week,  according to a person familiar with the matter.

Ironically, Chinese vaccine makers were initially at the forefront of the research, but China’s rapid control of the contagion left them scrambling to find places to carry out the vital third-stage clinical trials as U.S. rivals leapt ahead. Chinese companies now have third-phase trials running in at least 16 nations, with state-backed China National Biotec Group Co. testing from Argentina to Morocco; Sinovac Biotech Ltd. enlisting Brazil, Turkey and the Philippines among others; and CanSino Biologics Inc. testing in Pakistan, Mexico and Saudi Arabia.

Authorities at Brazil’s Butantan Institute, which is helping conduct clinical trials for the Sinovac vaccine, said on Dec. 23 the shot was more than 50% effective, meeting a minimum standard set by U.S. regulators for emergency authorization of Covid vaccines. It did not provide details, citing Sinovac’s request to reconcile data across different trials. The Brazil trial is Sinovac’s biggest so far with some 13,000 participants. A trial in Turkey indicated the vaccine is more than 91 percent effective, though it’s considered inconclusive as it was calculated from only 29 cases, compared with the 170 found in Brazil. Vaccines from Pfizer and Moderna Inc. have produced results well over 90%.

“In a country where the Chinese vaccine is the only one available, you either accept it or not,” said Yanzhong Huang, a senior fellow for global health at the New York-based Council on Foreign Relations. “But when you have choices between different vaccines, people are rational. They’re certainly going to choose Western-made vaccines because they’re the No. 1 choice, the data is already available, and they’re safe. China, so far, they haven’t had any systematic data available.”

CNBG and CanSino didn’t respond to Bloomberg’s requests for comment. A spokesman at Sinovac referred to recent press conferences in Beijing where health officials said the inactivated shots undergoing phase III trials and approved for emergency use have been found to be safe, with only mild side effects, and that there is a mechanism in place to follow up with those who get the shots. A Sinovac spokesman separately said the company could only disclose efficacy data after they are reviewed by Chinese regulators.

Few places have seen the issue become more politicized than Brazil, South America’s largest economy and the third-most infected country after the U.S. and India.

Brazilian President Jair Bolsonaro, known as the “Trump of the Tropics,” has repeatedly attacked “Made in China” vaccines, even as political opponent Joao Doria, governor of Sao Paulo, endorsed the Brazilian-Chinese effort by Sinovac and the Butantan Institute.

“We won’t buy it from China, it’s my decision,” Bolsonaro said in a radio interview in October. “It’s a matter of credibility — there are other vaccines that are more trustworthy.”

The government later backtracked on his statement. On Dec. 21, Doria said Sao Paulo would receive 5.5 million doses of the Sinovac vaccine within days.

Still, a survey by polling institute Datafolha earlier in the month showed that half of Brazilians wouldn’t take the Sinovac-Butantan shot, the highest refusal rate among all the vaccines. Some 36% of respondents said they’d also reject a Russian vaccine, while 23% said they wouldn’t take a U.S. shot.

The politics and public concern translate into hard economics for China’s drugmakers. When Brazil’s Health Ministry delivered a national immunization plan to the Supreme Court, it included a total of 300 million doses from AstraZeneca, Pfizer and Covax, according to the newspaper O Estado de S. Paulo. Sinovac’s vaccine wasn’t mentioned.

“Our regulatory agency is going to evaluate the data for efficacy and safety, but this needs to be well communicated to the population,” said Natalia Pasternak Taschner, a microbiologist and founder of Instituto Questão de Ciência, a Brazilian non-profit that promotes science in policy making. “It’s quite a challenge to do so when the president and the federal government are the ones raising issues about the vaccine being made in China.”

China may also be overestimating its ability to simultaneously vaccinate its own 1.4 billion population and meet the demand of hundreds of millions more in populous developing nations, said Huang at the Council on Foreign Relations, who has testified before U.S. congressional committees. CNBG said it is capable of making 1 billion doses of its inactivated vaccines, while Sinovac can produce 600 million doses, based on existing facilities and ones set to be completed soon. CanSino said it could make 200-300 million doses of its viral vector vaccines.

If Chinese vaccines aren’t available, developing nations will turn to other suppliers “and China will lose leverage,” Huang said. “We’re not just talking about the economic loss — diplomatic and strategic gains will also will be undermined.”

For the more than 6 billion people who live in developing nations, access to a vaccine soon could help reverse the devastating economic impact, particularly for the poor and those in the informal economy. Some national leaders are trying to reassure citizens about getting inoculated.

“I will be vaccinated first,” Indonesian President Joko Widodo said in a statement in mid-December. “This is to give people the trust and confidence that the vaccine we use is safe.” Indonesia has ordered 125.5 million doses from Sinovac, as well as 30 million from Maryland-based Novavax Inc. and is developing 57.6 million of its own shots. It’s also seeking doses from Covax, AstraZeneca and Pfizer.

Sheikh Mohammed Bin Rashid Al Maktoum, the prime minister of the United Arab Emirates and ruler of Dubai, received the Sinopharm vaccine on Nov. 3. “We wish everyone safety and great health, and we are proud of our teams who have worked relentlessly to make the vaccine available in the UAE,” he wrote on Twitter alongside a photo of him receiving the vaccine.

Such official endorsements may be enough to persuade some people to accept any inoculation if it receives approval.

“I would be glad to receive a vaccine, regardless of whether it’s Chinese-made or otherwise, so long as it’s proven to be safe, effective and to have no long-term side effects,” said Francis Chung, a 29-year old finance manager who works for a Malaysian plantation company. “It should also be endorsed by the relevant authorities.”

But many others remain skeptical. A survey in Kenya reinforced the concern that not all vaccines are equal. Africa-focused polling company TIFA Research found that respondents were least likely to take vaccines made in China and Russia, preferring vaccines from the U.K. or U.S.

If global leaders fail to persuade their citizens that all the vaccines they approve for use are equally safe, they could face a backlash among those who believe they are being given a second-rate option. Even in Hong Kong, where China has expanded its grip on power this year, leader Carrie Lam reversed course on Dec. 23 and said residents can choose whether to take the Pfizer, Sinovac or AstraZeneca vaccines.

“Transparency is needed in order to support more general public acceptance of the Covid-19 vaccines,” said Nicholas Thomas, an associate professor in health security at the City University of Hong Kong. “Absent such data, it is all too easy to see a two-tier perception of vaccines emerging.” — Bloomberg