Problems with two Chinese-made vaccines — one of which was distributed to clinics and possibly injected into hundreds of thousands of children — have led to arrests and made international headlines. But researchers who study vaccination in China don't expect a major effect on the country's high immunization rates.

Widespread support for immunization programmes combined with strict vaccine requirements for children starting school means that most parents will continue vaccinating their children, they say.

“I don’t think there’ll be an appreciable drop in vaccine coverage but it could impact when people get vaccines, and where the vaccines come from,” says Abram Wagner, an epidemiologist at the University of Michigan in Ann Arbor who has interviewed Chinese parents about their views on immunization.

Production problems

On 15 July, China’s national drug watchdog revealed that during a surprise inspection of vaccine maker Changchun Changsheng Biotechnology’s facilities in the northeastern province of Jilin, it found the company had faked production data for several batches of rabies vaccine. Authorities ordered that the doses be disposed of and revoked the company’s manufacturing permit for that vaccine; it is not clear whether anyone received the faulty doses.

Five days later, local government investigators announced that the same company had violated standards in making about 250,000 doses of the DTP vaccine, which protects against diphtheria, tetanus and pertussis (whooping cough), rendering the doses potentially ineffective. For that breach, the company says it was fined 3.44 million yuan (US$505,000).

It is not known how many children received the faulty DTP vaccines, which were recalled when the problem was uncovered by authorities in November, but so far no health issues have been reported. The main concern is that these vaccines won’t protect children from the dangerous infections that they’re meant to combat, says Wagner.

Parents turned to social media to voice their anger at the company and their concerns about domestic vaccines. But Xiaomin Wang, a social scientist at Zhejiang University Institute for Social Medicine in Hangzhou, agrees that the scandal is unlikely to reduce child immunization rates.

In 2016, when Chinese authorities discovered that childhood vaccines rendered ineffective by improper storage had been distributed to medical clinics across the country over five years, Wang and her colleagues went out and asked parents about their views on vaccines. They found ¹ that parents had very low faith in the safety of domestically produced vaccines, which make up 95% of vaccines given in China — only 11% said they trusted them. But the researchers also found that more than half of parents surveyed still intended to rely on them to vaccinate their children.

The disparity between parents’ trust in domestic vaccines and their willingness to use them is probably influenced by several factors, including cost and availability, says one of Wang’s collaborators on the survey, Leesa Lin, who studies social behavior and risk perception at the Harvard T.H Chan School of Public Health in Cambridge, Massachusetts.

Although the government subsidizes many domestic-made vaccines, those who have access to and can afford foreign-made vaccines are likely to seek them out, says Lin. “When an incident like this happens, the public might seek safer alternatives but would not give up on vaccination,” she says.

She attributes this, in part, to a widespread understanding of the benefits of vaccines, after decades of government campaigns promoting immunization. China has one of the world’s highest vaccination coverage rates — for example, 99% of Chinese infants receive the required three doses of the DTP vaccine, compared with 85% of infants globally, and 95% in the US. Lin and the team are about to submit for publication results from another survey, which confirmed parents strongly-held faith in the benefits of vaccination programmes.

Those results stand in contrast to the attitudes of some small groups of parents in Europe and the United States who resist vaccinating their children, citing unfounded safety concerns or religious reasons, says Lin. “In China, those factors do not play much of a role.”

Lin and Wang plan to survey parents again in the coming months to improve understanding of the factors that influence their decisions.

Wagner notes that the DTP vaccine is mandatory for children starting school in China and credits such requirements with the country's high vaccine uptake. Some parents might delay vaccination in the wake of the latest scare, but they are unlikely to risk their child being denied entrance to school, he says. He adds that it's particularly hard to get an exemption from such requirements in China compared with other countires that have similar rules.

Repair trust

Wagner hopes that Chinese officials will be more transparent about what happened at Changchun Changsheng than they were during the 2016 scandal and take stronger action to prevent another incident. At the time, the government promised to improve oversight of vaccine manufacturing and transportation, he says. “They talked big, but I’m not exactly sure what they did,” he says. “I hope that they’ll learn some lessons from this event and implement tighter regulations.”

There are already encouraging signs. Several Changchun Changsheng executives, including the chair, have been arrested, and Chinese President Xi Jinping has said that the events are shocking and has ordered an investigation of the vaccine production chain. “This is a step forward compared to last time,” says Lin.

China’s vaccine makers will also have to convince international markets that their vaccines are safe and effective if the country is to become a major global producer, says Wagner. “Vaccines and pharmaceutical products could be a huge industry for them.”