evidence: "Vaccines are among the most powerful inventions in history, making once-feared diseases preventable," said WHO Director-General, Dr Tedros Adhanom Ghebreyesus. "Thanks to vaccines, smallpox has been eradicated, polio is on the brink, and with the more recent development of vaccines against diseases like malaria and cervical cancer, we are pushing back the frontiers of disease. With continued research, investment and collaboration, we can save millions more lives today and in the next 50 years."