It is a well-established that contraction of measles has a
lasting impact on the immune system predisposing the individuals affected to
opportunistic infections. The period of vulnerability
was thought to last for months. In fact,
it has recently been shown that this deleterious impact on the host’s immune
system can persist for over 2 to 3 years.
This is of particular concern to public health professionals especially
in those parts of the world where the measles immunization regimen is poorly
administered or in those regions where there is a complete lack of
infrastructure for the delivery of health care.
Public health data shows that wherever mass measles immunizations are employed
childhood mortality is lowered by 30 to 50% in so-called resource-poor
countries and up to 90% for impoverished populations.
It has been of interest to determine the mechanistic explanation
for this apparent lost in immune-competency in individuals infected by the
measles virus. The suspicion has been
that measles infection results in the loss of the host’s immune system
memory-cell population – a condition referred to as “immune amnesia.”
Dr. Michael J. Mina and his colleagues at the Department of
Ecology and Evolutionary Biology at Princeton University, Princeton NJ were
able to confirm through epidemiological data that, in fact, measles infection
leads to the ablation of those T and B lymphocytes responsible for immunological
memory thereby leaving patients susceptible to opportunistic infections. Children in this group are particularly prone
to increased mortality in this setting.
In addition, the data also unambiguously demonstrated the
efficacy of measles vaccination in preventing potentially lethal opportunistic
infections that would otherwise spread through susceptible populations impacted
by uncontrolled measles infections.
These finding are of particular interest in terms of improving public
health on a global basis.
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