[Kamendoriks]

POLIO:

Lets discuss about a single communicable disease for simplicity sake. Polio.


In pre-vaccination era, polio was found in all countries of the world. The extensive use of polio vaccines since 1954 eliminated the disease in developed countries. . Implementation of eradication strategies has reduced the number of polio endemic countries from more than 125 in 1988 to 4 in Nov, 2006. These countries are India, Afghanistan, Pakistan and Nigeria. Ten other countries have reported cases of imported virus.
[Pg No.166, Park's Textbook of Social and Preventive Medicine 19th Edition]
Well 125 countries with polio reduced to 4 countries with the introduction of Polio vaccine. Well if we are talking about numbers that was saved by a Polio vaccination, it will be Billions.


Edit:
I wanted to add a point about the 'numbers' that have side effects from polio vaccination. OPV (oral polio vaccination) is the vaccination recommending by WHO. Lets see what is the 'numbers' that have complications.

OPV is remarkably free from complications.
The WHO has estimated the risk of vaccine-associated paralysis to be about 1 case per million vaccinees, and the risk of a close contact of a vaccinee devoloping paralytic polio, about 1 case per 5 million doses of vaccine.
[Pg No.170, Park's Textbook of Social and Preventive Medicine 19th Edition]

Bottomline:
There is a 1 in a million chances of a side effect from vaccination. But not being vaccinated has multiple times the risk of getting the disease. Eradication polio from All the countries in the world except 4 is itself proof of its benefit.

The Prophet has adviced us : "Make use of medical treatment, for Allah has not made a disease without appointing a remedy for it, with the exception of one disease, namely old age." Sunan Abu-Dawud. 3846 . But its your personal choice to vaccinate or not.

May Allah save us all from disease. Ameen.