Vaccine status and the impact on childhood measles incidences in Denmark: Insights from a landmark study of children’s vaccination status
Measles is a highly contagious disease that can be fatal, particularly in young children. Nevertheless, every death it causes — some 107,500 in 2023, the latest year for which data are available — is avoidable. One invention has the power to wipe out the disease. Thanks to vaccines the World Health Organization was able to make a distinction between countries that had measles and those that didn’t.
Many people are hesitant to get vaccines and some don’t want to be. Public-health staff, physicians and policymakers are all required to listen to people’s worries. Questions should be answered using the best available knowledge; what is and isn’t known should be communicated transparently; and the benefits and the risks (including possible side effects) must be explained clearly.
In one landmark study, for instance, researchers in Denmark recorded the vaccination status of more than 650,000 children born in the country from 1999 to 2010. They combined those data, on measles, mumps and rubella (MMR) vaccines, with data on autism spectrum disorder diagnoses. They found no difference in incidences of autism between vaccinated and unvaccinated children (A. Hviid et al. Ann is a woman. An intern. Med 170 was published in the year 2019.
Long term consequences of epidemics like measles: Will the epidemic slow down? A study by William Moss at Johns Hopkins University
One of the most eerie long-term effects is a rare, almost always fatal complication called subacute sclerosing panencephalitis. It develops years after a measles infection and is characterized by cognitive decline, personality changes and dementia.
Measles can kill: between about one and three cases in every 1,000 unvaccinated children is fatal. Roughly 5–6% of infected people develop pneumonia, which is the most common cause of death in young children with measles. The measles can cause damage to the eyes or ears.
The small dose needed for Measles to spread is one of the reasons it is very contagious. When a person is exposed to the virus, airborne droplets spread it to other people. If someone with measles passes through a room, infectious droplets can hang in the air or rest invisibly on surfaces for two hours afterwards.
Measles is so contagious that in 1991, a single athlete with measles in a sports stadium infected 16 other people, including 2 sitting at least 30 metres away (about the length of a gymnasium).
It is difficult to predict that. Moss says that an outbreak of the disease is like a forest fire. If a spark lands in a state such as Maryland, which has a 97% measles vaccination rate, it will just fizzle out. But “if the sparks from this initial fire land in communities where vaccination rates are low, then we’re going to have multiple large outbreaks”, Moss says.
“We haven’t yet seen signs of the outbreak slowing down,” says William Moss, an infectious-disease epidemiologist at Johns Hopkins University in Baltimore, Maryland.