Vaccination against measles has led to a worldwide reduction of child death. However, the observed decrease cannot entirely be explained by elimination of the measles virus. Scientists from the Princeton University in New York and the Erasmus University Medical Centre in Rotterdam presume that the measles vaccine prevents weakening of the immune system after a measles infection, as was published in Science.
Researcher Rik de Swart of the department Viroscience in the Erasmus MC explains: “The measles virus predominantly infects cells of the immune system, preferably memory T cells. The immune system reacts by eliminating the virus, but simultaneously kills many memory T cells in the process.” As a result, children are more susceptible for infections in general.
The scientists compared child deaths caused by measles and other infections during several decades in the US, England and Denmark. The author, Michael Mina, medical student at the Emory University School of Medicine in Atlanta, says: “Our results suggest that the adverse effects of measles are much more lasting.” Before, the infection-vulnerable period was estimated to be several weeks to months, yet, the new evidence suggests a duration of two to three years.
With the measles vaccine children could not only be protected against the direct effects of measles, but also against secondary infections. Although the results point at a strong correlation, a causal relationship has not been proven yet. For example, the researchers still need to show that the children who had measles, were the ones dying from other illnesses.
Sources: Science, Erasmus MC
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