Connect with us


The Daring Doctor Fighting HPV Vaccine Stigma in Japan

By fighting misinformation about the HPV vaccine to save lives, medical doctor Riko Muranaka has shown the cost and value of defending scientific integrity.



Riko Muranaka receiving the 2017 John Maddox award at the Royal Pharmaceutical Society. (©Jwslubbock/CC BY via Wikimedia Commons)

"Japan has one of the highest vaccination rates against COVID in the world," Riko Muranaka says with some pride. The medical doctor has been at the forefront of the vaccination effort, albeit for a different vaccine

For years, the Hokkaido University graduate has pushed back against misinformation on the Human papillomavirus (HPV) vaccine. The virus causes cervical cancer and, less frequently, other types of cancer. Every year, 3,000 women die of cervical cancer in Japan alone. Almost all of these deaths could be easily prevented with a vaccine against the virus. 

In 2013, Japan rolled out the HPV vaccine for girls. However, the government withdrew its recommendation only months later. Anti-vaccine campaigners claimed that the vaccine caused all kinds of dangerous side effects ranging from seizures to heart diseases and chronic pain. 

As a result, the vaccination uptake fell from over 70% to less than 1%. "The government was afraid," explains Muranaka. She says that the government knew perfectly well that the vaccine was safe. However, it was reluctant to confront the movement, which was spinning all sorts of horror stories about the shot.

The HPV vaccine, Gardasil, is administered to a patient in Japan. (©melvil/CCBY via Wikimedia Commons)

A Media Frenzy

Because of this, sketchy claims and fabricated science about the vaccine got prime time in Japanese media. There were protests by angry parents and girls in wheelchairs. It all sparked panic despite the fact that there was no evidence to back up the anti-vaccine group's allegations. 

Muranaka contrasts the frenzy with the calm and clear path of the COVID vaccine launch. She believes that the HPV saga taught the government a lesson. "In the case of COVID, doctors were very quick to dispense any hesitancy." She believes this is one of the reasons Japan has one of the highest vaccination rates in the world, at more than 80%. "They did not want to repeat this [mistake]," she explains.

Granted, Muranaka admits that the pandemic made it easier for the government to roll out the COVID vaccine. The people were more afraid of the virus than of the new vaccine. But she is unequivocal in her assessment: "Do not hesitate to fight back as soon as you see signs of vaccine hesitancy. It takes a long time to recover trust."

Riko Muranaka
Riko Muranaka receiving the 2017 John Maddox award at the Royal Pharmaceutical Society. (©Jwslubbock via Wikimedia Commons)

Unsound Science

The story of the HPV vaccine made this abundantly clear. In fact, it took eight years and eight months for Japan to reverse its decision. Soon after the government scrapped its recommendation in 2013, Muranaka started to promote the HPV vaccine in Japanese newspapers. She also went to investigate the study by medical doctor Shuichi Ikeda. He was showing slides of damaged mice brains on TV and claiming that the vaccine had affected the rodent's nervous system. 

"The study was never published," Muranaka says. Ikeda was then a dean and professor at Shinshu University in Nagano Prefecture. But he has since left his post after the university formed a committee to investigate his experimental findings and found no evidence that his research was backed by sound science. 


As it turned out, Ikeda and his team based their results on data from a single mouse and that animal had not even received the vaccine. But it had been Muranaka who first set the frenzy in motion. 

Electron micrograph of Human Papilloma Viruses (HPV). (©Dr Graham Beards via Wikimedia Commons)

The Court Battles Begin

Her activism came at a high price. She received personal threats and was shunned by the media. Publishers even declined to publish her book. Ikeda sued Muranaka for libel, alleging that she had damaged his reputation as a scientist. In March 2019, a Tokyo court ruled against Muranaka and handed a victory to Ikeda and his followers. 

Muranaka appealed, only to lose her case again in October 2019 in a retrial before the Tokyo High Court. It demanded Muranaka pay ¥3.3 million JPY (about $25,000 USD) in compensation. Her legal dispute made it all the way to the Supreme Court, which dismissed the case in March 2020. The lower court's decision was final, and she was found guilty of libel in the defamation case.

Nobel Prize Winner Steps In

By then, however, Muranaka had gained the powerful backing of Japan's Nobel Prize winner Tasuku Honjo. He received the prize in 2018 for his groundbreaking work on the role of the immune system in fighting cancer. The immunologist from Kyoto University even wrote an expert opinion for the court backing Muranaka in the lawsuit. 

However, it did not alter the view of the judges. They based their ruling not on the assessment of the scientific accuracy of Ikeda's findings, but solely on the impact of  Muranaka's usage of the word "fabrication" to harm Ikeda's reputation. 

But public opinion had been slowly shifting. For her effort, Muranaka received the 2017 John Maddox prize, which honors individuals for promoting sound science and evidence on matters of public interest in the face of hostility. 

"As a doctor, I can’t overlook the claims that endanger lives. As a journalist, I need to tell people the truth. That is why I started writing for the media," Muranaka said in her acceptance speech. 

She thinks that all of this finally made the media reluctant to give airtime to the antivaccine activists. "Before, they were so afraid of getting attacked by them."

Tasuku Honjo at the Nobel Prize press conference in Stockholm in December 2018. (©Bengt Nyman via Wikimedia Commons)

A New Start

Finally, the government reversed its decision and restarted the HPV vaccination campaign. Since April 2022, after eight years and eight months of suspension, the government has been recommending the HPV vaccine again — a major victory for Muranaka. "It is partly thanks to her effort that the government reversed its decision last year," says editor Dennis Normile of the academic journal Science

However, the legal battle is not over yet. There are still court cases pending against municipalities and cities by antivaccine groups. And after years of not vaccinating girls against HPV, the rollout campaign needs to get back on track. Presently, the uptake is around 30% in the recommended age group — still some way to go. "We could have done better," says Muranaka. 



Author: Agnes Tandler

Our Partners