What risk does an unvaccinated child pose to your vaccinated child? Does the vaccine work or not? #9 | Posted by mdog1 at 2015-01-22 09:18 PM
Although highly effective, the measles vaccine is not 100% effective.
www.cdc.gov ( >= 99% after two doses) In addition, very young infants and those with compromised immune systems may not be able to take the vaccine.
Even if the vaccine is 99.9% effective, that means that out of 300 million vaccinated Americans, ~300,000 Americans would still be at risk. This does not take into account the 4 million infants who are too young for their first vaccine dose, the 20 million or so children who have not had their second dose (resulting in a 94% effectiveness which places about 1.2 million at risk) and those others who are immunocompromised or pregnant and therefore cannot be vaccinated.
Vaccines work not by ensuring the no one can get sick, but by protecting enough people from infection so that the disease cannot obtain enough vectors to pass on to others. Those who refuse the vaccine present a risk to many others, even the vaccinated.