An Info-graph illustrating the key reasons that led India to miss the child mortality targets which are a part of the MDGs.
Monday, 28 September 2015
How india missed the 2015 child mortality target?
An Info-graph illustrating the key reasons that led India to miss the child mortality targets which are a part of the MDGs.
Friday, 11 September 2015
All you need to know about ‘Herd Immunity’
Herd Immunity is a form of immunity
that occurs when a significant portion of a population is vaccinated and in
turn provides a measure of protection for the individuals who have not
developed immunity. When this critical percentage of the population is already
protected through vaccination against a virus or bacteria, it makes it
difficult for a disease to spread because there are few vulnerable individuals
left to infect.
The term herd immunity was first
coined in 1923, recognized as a naturally occurring phenomenon in the 1930s
when it was observed that after a significant percentage of children had become
immune to measles, the number of new infections temporarily decreased,
including among vulnerable children. Mass vaccination in order to
actuate herd immunity has since become common and proved successful in
preventing the spread of many contagious diseases. During the smallpox
eradication campaign in the 1960s and 1970s, the practice of ring
vaccination, of which herd immunity is integral to, began as a way to
immunize every person in a "ring" around an infected individual to
prevent outbreaks from spreading.
This is highly effective in
stopping the spread of a disease in a community. It is particularly crucial for
protecting people who cannot be vaccinated. These include infants who are too
young to be vaccinated, immunocompromised people, and those whose medical
condition doesn’t allow them to receive vaccination (such as cancer patients).
However the percentage of a
population which must be immunised in order to achieve herd immunity against a
specific disease varies for each disease. Once a certain threshold has been
reached, herd immunity gradually starts eliminating a disease from a population.
This elimination, when achieved worldwide, results in the permanent reduction
in the number of infections to zero, called eradication. Till date, two
diseases have been eradicated using vaccination and herd immunity: smallpox
and rinderpest.
However, when immunisation rates
decline, it becomes difficult to retain herd immunity, leading to an increase
in the number of new cases.
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