Anti-vaccination and stretching the limits of herd immunity

Crap. A bunch of people (helped a lot by Jenny McCarthy and Oprah) are touting the rubbish that children can be hurt by the standard childhood vaccinations and that concerned parents should not allow their children to be vaccinated. Fortunately for these defenseless children, a thing called Herd Immunity protects them as long as a specific percentage of the overall population remains vaccinated. Below that percentage, all bets are off. Also, if the percentage is too low, people who have been vaccinated are also at risk as the vaccines immunity will lessen over time. For adults, this is particularly bad as 'childhood' diseases like Chicken Pox and Mumps have the potential to be life-threatening when you are an adult. From the BBC:

Measles outbreak 'worst in years'
Health chiefs in Wales are dealing with a "massive" measles outbreak, with numbers already four times the highest figure recorded over the past 13 years.

Four nursery school children were treated in hospital as part of 127 cases across mid and west Wales, while there are another 35 cases in Conwy.

The National Public Health Service (NPHS) in Wales saw 39 cases last year. Its highest figure in 2003 was 44.

Officials appealed for parents to take up the MMR vaccine.

Dr Mac Walapu, consultant in communicable disease control for the NPHS, said: "For as long as there are children who do not receive their MMR vaccinations, there is the potential for outbreaks of measles to happen and we would remind anyone in Wales, and not just in the affected area."

A spokeswoman added: "We need to be up front with parents."

She added: "We try not to be too scary when we talk to people about this, but children die of measles and children are impaired by measles. "It puts children in hospital. The reality it is that this is happening now, in Wales. Measles is very contagious."

Hat tip to Charles for the link.