Vaccine success stories

 

Infectious diseases causing large scale deaths have been recorded across the world since pre-historic times. When humans started living in communities, the spread of infections got easier and this resulted in epidemics. There have been records of such epidemics due to plague, chicken pox, small pox, typhoid, cholera, malaria, influenza, measles, tuberculosis and yellow fever.

Successful elimination of the demon called small pox with vaccine

The devastation caused by small pox is quite well known. It is estimated to have killed more people than all wars in history. Smallpox is a dangerous viral infection caused by the variola virus. It spreads from person to person through air or contact. It is highly infectious and can spread like wildfire to claim the lives of thousands and leaving hundreds blinded or scarred for life.

In the late 18th century, it was Dr. Edward Jenner who noticed that people exposed to cowpox became resistant or immune to smallpox. He then tested this observation by inoculating a boy with cowpox pus and later exposing him to smallpox. The experiment was a success and the concept of vaccination for prevention took birth.

In 1950, the first large scale endeavor to eradicate small pox in the Americas was undertaken. This effort slowly started bearing the fruits of success and there were no reported cases of small pox in the United States…but small pox remained a threat in less developed countries.

Realizing the importance of a world-wide crusade if lives were to be saved, the World Health Organization initiated a global eradication program for the banishment of small pox through inoculation. The global eradication effort, led by D.A. Henderson strived to achieve at least 80% vaccine coverage in each country. The drive used a method called as “Ring vaccination” which meant that every person who could have been exposed to a smallpox patient was tracked down and vaccinated as speedily as possible, effectively curtailing the spread.

This drive was a great success…so much so that the last naturally-acquired case of the variola major was identified in Bangladesh in late 1975 and the last case of illness caused by the less virulent strain (variola minor) occurred in Somalia in 1977. 1

The World Health Assembly declared that smallpox had been eradicated from the face of the earth in 1980. The conquest over small pox is indeed one of the greatest accomplishments of mankind in the 20th century and a milestone in the journey of vaccination.

The eradication of smallpox is indeed a triumph of public health.

Controlling the Dreadful Polio

 

It was not too long ago that polio was the most dreaded disease disabling millions of children.

Spreading through contaminated water and from person to person contact, mankind has not found a cure for this disease. But vaccination has resulted in eradication of polio from many countries. Dr. Jonas Salk invented the polio vaccine that went on to save millions of children after its acceptance in 1955 when it was declared “safe, effective, and potent” by the University of Michigan Polio Vaccine Evaluation center. 2 According to history.com 3, Salk started doing research in the 1930s. He is famous for first testing the polio vaccine on himself (and also his family members).

The common symptoms of polio are sore throat, fever, tiredness, nausea, headache, and stomach pain. But within hours, this can turn vicious, causing weakness in arms and legs, meningitis and paralysis disabling a person for life.

The availability of polio vaccine and its compulsory administration has been responsible for controlling this disease and even eradication from many parts of the world. The Center for Disease Control states that 99/100 of children who are at risk and get vaccinated avoid contracting the disease 4.

India has not a reported case of polio for three years, but dense population and poor sanitation puts our country at a high risk of new outbreaks.

Yellow Fever

Yellow fever occurs in tropical countries in Africa and South America where is caused wide epidemics in the seventeenth, eighteenth and nineteenth centuries. The yellow fever virus (YFV) was first isolated in 1927 by American and French scientists; from where began the development of the vaccine for yellow fever.

Today, yellow fever is being controlled in these regions by routine immunization of children 6 months and older, massive vaccine campaigns to prevent epidemics, keeping a vigil to detect outbreaks and act rapidly, as well as control of the mosquito menace that helps spread the disease. Travellers from foreign regions are made to take vaccinations compulsorily before travel to these areas.

Symptoms of yellow fever are headache, fever, jaundice, muscle pain, nausea, vomiting and fatigue. A small proportion of patients who contract the virus develop severe symptoms and approximately half of those die within 7 to 10 days.

Hence, prevention through widespread vaccination is the only way to control this deadly disease. Significant progress in combating the disease has been made in West Africa and more than 105 million people have been vaccinated in mass campaigns. No outbreaks of yellow fever were reported in West Africa during 2015 2. Continued efforts are still required before further success can be achieved.

 

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References:

  1. Belongia EA, Naleway AL. Smallpox Vaccine: The Good, the Bad, and the Ugly. Clin Med Res. 2003 Apr; 1(2): 87–92.
  2. Factsheet on Yellow fever by WHO 9update May 2016; accessed on 8th March 2017.
  3. http://www.hindustantimes.com/india-news/a-shot-at-life-how-india-plans-to-immunise-all-its-children/story-ZxplUKqUaE3GNMqtpZY8sL.html