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Measles and Measles Prevention
Measles virus (MeV) is a respiratory virus of the paramyxovirus family found specifically in humans. This highly contagious virus spreads easily through droplets in the air and as a result of close contact with the body fluids of an infected person. Measles often starts with a high fever, which begins about 10 to 12 days after exposure to the virus. At about 14 days after exposure measles causes a characteristic sore rash of red-brown spots over the body, fever, runny nose, diarrhea and sometimes pneumonia; these symptoms usually last for 5-6 days. In rare cases it can cause encephalitis (infection of the brain) and death. In pregnant women, a measles infection can cause a miscarriage, premature births and low birth weights.
Measles has been a preventable disease in Canada for over 50 years. The first measles vaccine was introduced into Canada in 1963, after 10 years of research and development.
The American virologist, John Enders and pediatrician Thomas Peebles were the first scientists to isolate a strain of the measles virus (called the Edmonston strain, after the boy they retrieved the virus from) in 1954. Enders then established a method for cultivating (growing) sufficient quantities of the virus to make a vaccine and developing a method for attenuating (weakening the ability of the virus to cause illness) by passaging it through different living tissues. The method of passaging (or serial passaging) involves culturing the virus many times over, in different tissues from different sources. It took Enders and Samuel L. Katz three years of passaging to create a strain that was safe for testing, and then another seven years of animal testing and clinical trials in humans before the vaccine was licenced.
Remarkably, within a few years of its introduction in 1963, the measles vaccine had essentially wiped out measles in North America. In 2011, the Centres for Disease Control in the United States reported a 99% reduction in measles cases since the pre-vaccination era. Similar reductions in the incidence of measles were experienced in Canada (See Figure 1).
In 1971, the first combination measles-mumps-rubella (MMR) vaccine became available in the United States, developed by the prolific American vaccinologist Maurice Hilleman. This trivalent vaccine (containing three virus strains) has been the standard for routine vaccination since 1983. In 1996-97 the routine one-dose MMR vaccination was changed to a two-dose regime for routine vaccination because of occasional breaks in immune response with the one-dose vaccination program. In 2005, chicken-pox immunity was also added to the mix with the introduction of a measles-mumps-rubella-varicella (MMRV) vaccine.
Unlike some other viruses, there is no known antiviral medication that can treat a person with measles. Most people will recover with rest and supportive care that includes good nutrition, adequate fluid intake and treatment of dehydration. The best way to deal with measles infections and outbreaks is to prevent them through widespread vaccination programs. Routine childhood immunization for measles requires two doses of measles-containing vaccine (MMR or MMRV). The first dose is given at 12 to 15 months of age and the second dose at 18 months of age or any time after, but before a child enters school. If a large enough group of people within a population are vaccinated, the chances of the odd person who is not vaccinated getting the disease is greatly reduced. This concept is called community immunity (or herd immunity).
The MMR vaccine had a remarkably untarnished safety record until 1997, when it became embroiled in a supposed autism connection due to the fraudulent research of Andrew Wakefield. (See Fraudulent Research) Since then the MMR vaccine/autism link has been completely discredited by many scientific investigators. Misinformation in the media and the ant-vaccination campaigns of various celebrities based on this fraudulent study have had an impact on the public trust of vaccines, with some parents opting out of having their children vaccinated. As a result, there have been an increasing number of outbreaks of measles infections in some previously measles-free communities in recent years (See Measles, Misinformation and the Media).
Despite having a safe and economical vaccine since 1963, measles is still one of the leading causes of death of children under the age of five in the world. Ongoing mass vaccination campaigns have been taking place in many of the high-risk countries and these initiatives have dramatically dropped the incidence of the disease globally. Between 2000 and 2012 the World Health Organization reported a 78% global drop in the number of deaths due to measles, from 562 400 to 122 000, and an emphasis on eradicating this disease continues.
The measles vaccine is considered one of the greatest public health innovations of the 20th century and it will continue to be a key medical tool in controlling measles infections.
American Association of Immunologists. John Enders. (Accessed August 14, 2014)
Immunize Canada. Measles. (Accessed August 14, 2014)
Pediatrics. The First Measles Vaccine. (Accessed August 14, 2014)
Nature Medicine. 11, S2 (2005) Profile: Maurice Hillman (Accessed May 15, 2014)
World Health Organization. Measles, Fact sheet N°286. (Accessed August 14, 2014)
History of Vaccines.org. Timeline of Measles. (Accessed August 14, 2014)