Editorial: Combating disease and promoting health: challenges for health research

Health challenges at global, regional and national levels are constantly changing with time, due to the impact of many different factors. Considerable progress was made in the 20th century in combating infectious diseases with the development of drugs for the treatment of bacterial infections and a wide range of metabolic disorders as well as vaccines to prevent some bacterial and viral infections. Achievements included the eradication of smallpox and progress to- wards eradication of polio. However, major challenges now arise from new, emerging and re-emerging infectious agents. In paral- lel, the epidemiological transition towards noncommunicable diseases that was per- ceived as a characteristic of affluence is now being seen in many low- and middle- income countries, presenting a new range of challenges for prevention, diagnosis and treatment of these chronic conditions.