Riko Muranaka is a medical doctor, journalist and recipient of the 2017 John Maddox Prize for fighting to reduce cervical cancer and countering misinformation about the human papilloma virusvaccine dominating the Japanese media, despite facing safety threats. Despite the lack of evidence, the HPV vaccine is infamous in Japan due to misattributed adverse effects, with government suspending promotion and coverage. While the World Health Organization safety and efficacy information about the vaccine is consistent with Muranaka's reporting, a court ruled against Muranaka in an unrelated slander lawsuit in 2016 for claims of alleged fabrication. Under threat of legal harassment by antivaccine activists, publishers declined some of her works including a book on the HPV vaccine.
In 2016, Muranaka wrote in the Wedge magazine about research done by Shinshu University neurologist Shuichi Ikeda, alleging that some results to demonstrate a link between an HPV vaccine and brain cancer in mouse had been fabricated, resulting in a slander lawsuit. While Japanese's Health Ministry stated that Ikeda's results "have not proven anything about whether the symptoms that occurred after HPV vaccination were caused by the HPV vaccine," the court ruled that evidence of fabrication was absent. The university investigation on Ikeda's work concluded that he did not commit scientific misconduct, but that conclusions may have been overstated, then released a statement, including that the research did not conclusively provide a link in relation to vaccine safety. Muranaka lost the slander case. Wedge magazine had to retract claims of fabrication from the article with both needing to pay for damages. Muranaka intends to appeal, also stating that she needs to win the lawsuit for science and that the court case was still an opportunity to make friends and gain recognition despite its negative aspects. According to Heidi Larson, director of the Vaccine Confidence Project at the London School of Hygiene & Tropical Medicine, "I think what is important is that media coverage does not distort the point and imply Dr. Ikeda's science won: It was Dr. Muranaka's manners and language that lost".
At the award ceremony of the John Maddox Prize, Riko Murunaka's speech highlighted the circumstances that, according to the award winner, could have given rise to the distinction received.
The WHO has evaluated the effectiveness and safety of the vaccine against human papilloma virus concluding that it is extremely safe and that it is not related to the adverse effects attributed to it. At 2016, 79 out of almost 200 countries have HPV vaccine programs for girls and adolescents. However, Japan stopped recommending vaccination despite the fact that its own technical committees found no relationship with the alleged adverse effects falsely attributed to this vaccine, and as a consequence, vaccination coverage fell to levels close to zero, not seen in no other country.