Virology, Emerging Diseases & vaccines

Measles as re-emerging infectious disease

Measles was once an eradicated disease in parts of the world after vaccines were developed and administered in at-risk areas. It is caused by the measles virus (MeV) which is a single stranded RNA virus with genetic diversity based on the nucleoprotein gene, including 24 genotypes. Measles complications which include pneumonia, diarrhea, vomiting and encephalitis are more common among children under five years old and adults. Humans are the only natural hosts of measles virus. However, measles has made a comeback partly fuelled by a growing ‘anti-vax’ sentiment, in which people refuse to vaccinate their children due to false public information. Measles is the most infectious disease in the world, with the capability to spread quickly and in great distance. So far, the disease is in Europe, Asia and the Americas, and threatens to spread further. Cases of measles can be dangerous to both adults and children, and in some instances the disease is deadly. Death rates are one to two in every 1,000 cases, and children are most at risk. It can be prevented by MMR vaccine. The vaccine protects against three diseases: measles, mumps, and rubella. One dose of MMR vaccine is approximately 93% effective at preventing measles; two doses are approximately 97% effective. Almost everyone who does not respond to the measles component of the first dose of MMR vaccine at age 12 months or older will respond to the second dose.