Adverse effects of single-component measles vaccine in school children.

Measles is a highly contagious viral infection potentially with serious complications and the principal method of protection from the disease is vaccination. Measles vaccination resulted in a 79% drop in measles deaths between 2000 and 2015 worldwide. There has long been a debate about the necessity and benefit-loss ratio of routine MMR vaccination due to possible AE of MMR vaccine. Especially in developed countries which are thought to be free of measles there is an increasing tendency towards hesitation for vaccination though there have been continued outbreaks of measles in countries in which measles is considered to be eliminated. Considering those facts, we decided to publish our data about measles vaccination and adverse effects (AE) during national catch-up measles vaccination programme which took place December 8-26, 2003. A total of 152.648 children aged between seven and fourteen were vaccinated by a live attenuated measles vaccine of which 148.064 (97%) had received measles vaccine by age nine or twelve months. During one month follow-up the AE were recorded. Totally 30.302 AE were reported in 24.209 children, of which 52% of them were local and pain and swelling at injection side were the most common AE. Fever and headache were the most commonly observed systemic side effects. All AE were mild and transient except in four children in whom encephalitis was diagnosed during the one month observation period. Further investigation of the etiology of those cases revealed that they were not related to measles or measles vaccine. In conclusion, single-component measles vaccine was found to be safe in previously MMR vaccinated children in short term and long term effects may be need to be clarified by further studies.