3 ms·
Not everyone needs to be vaccinated for the phenomenon of 'herd immunity' to kick in: http://en.wikipedia.org/wiki/Herd_immunity http://en.wikipedia.org/wiki/H
by DanI-S 15y ago
Not everyone needs to be vaccinated for the phenomenon of 'herd immunity' to kick in:
http://en.wikipedia.org/wiki/Herd_immunity http://en.wikipedia.org/wiki/Herd_immunity