Feb. 26 (UPI) -- Vaccinations remain the best way to stop the the spread of infectious diseases in epidemics, according to scientists in Italy.
They're more effective than quarantines, or doing nothing, during an outbreak of an epidemic, scientists from the Italian National Research Council and the Joint Research Commission concluded in a study published this month in the American Physical Society.
Widespread immunization programs in several parts of the world, including the United States and Europe, have virtually wiped out smallpox, polio and other fatal diseases. These shots are given to children on a regular schedule, but some vaccines also are given more than once, such as annual flu shots, while others are given less often or as needed, such as for pneumonia and shingles.
Researchers suggest in the new study that using vaccines as a weapon against epidemic outbreaks should be an obvious option to prevent the further spread of a disease.
"We show how, consistent with common sense, but contrary to common practice, in many cases preventing is better than curing: depending on network structure, rescuing an infected network by quarantine could become inefficient soon after the first infection," the scientists wrote in the study.
The study was published after an outbreak this year at the Winter Olympics, held in South Korea, in which 275 staffers and volunteers were infected by the norovirus.
Health officials attempted to initially contain the outbreak at the Olmpics by quarantining 1,200 employees who caught the virus. Despite these measures, the illness continued to spread and affected some athletes.
The scientists found that quarantining nodes quickly become ineffective. And even suggested that the "do nothing" approach is preferable to quarantine.
The researchers found that outbreaks were better contained with vaccination, even if a few number of people got the shot.
The scientists ran physics-based simulations on networks to replicate the way individuals interact with one another in the real world, including air transportation. The simulations are simplified versions modeling for real-world epidemics, such as Severe Acute Respiratory Syndrome, or SARS.
The scientists used a vaccination strategy based on "optimal percolation," which finds "the least set of nodes that, when removed from a network, can fragment it into small clusters," according to a press release.
"The idea behind this approach is that fragmenting the network ensures infections are contained within small groups, hence preventing the occurrence of large outbreaks," the researchers said.