Herd Immunity

[Tabitha8]

A simple title for what I think is probably a complex subject.

If we have herd immunity to an illness as a result of vaccinating our children, how is that maintained given that we don't vaccinate ourselves, the grandparents, our neighbours, etc?

I do think there is a difference if you commute somewhere like London LeBFG, you can come into very close contact with a lot of different people on a daily basis
But if you dont have children, drive to work and work in a small office then you really don't need to a lot of people around you to be immune to stop you getting a disease. I know before we had children, dh started to commute for a short while and started picking up one bug after another, which he never did before.

Yes indeed bruffin. Lifestyle will make a big difference to your exposure risk. The thing with epidemiological models is they deal in populations writ large, not micro-populations, or families or even individuals. It may seem improbable that a low vaccination rate will have any effect on whether you contract a disease or not, but where an individual isn't seeing too many people and the disease is not super contagious, I can easily imagine a low proportion of vaccinated people making a difference on disease incidence.

It just plain common sense, not sure why we need huge long threads on it.

Bruffin It was a health visitor who said to me that I should vaccinate my child in order to maintain herd immunity.
Then we hear the term "herd immunity" in the media whenever there is an outbreak of disease.
Here, on the BBC website, for example, during last May's measles cases, they talk about an uptake rate for the MMR required in order to stop the spread of disease:
www.bbc.co.uk/news/health-13561766
"HPA figures show that the number of toddlers getting the MMR vaccination is climbing steadily, but is still far from the 95% uptake rate needed to stop the spread of the disease in the community."

I think that this thread might, more sensibly, be suggesting that the above approach is too simple? It will vary from area to area and, as BFG said, from circumstance to circumstance?
Yet, there again, I do go on holiday. I travel abroad, I travel within the UK.

But as we've discussed, while there is indeed a threshold where a disease can't be sustained - even below that threshold, having more immunised children still reduces the probability of a non immune child being exposed to the disease.

Primarily you should vaccinate your child to protect him or her but even if you're below the threshold where a disease won't spread, you can maintain the herd immunity already achieved by keeping vaccination levels up. That must be what your hv meant.

"HPA figures show that the number of toddlers getting the MMR vaccination is climbing steadily, but is still far from the 95% uptake rate needed to stop the spread of the disease in the community."

Most people reading that would have the common sense to realise that 95% is not an all or nothing figure.

Not if you want to pretend that herd immunity is a myth so you can keep on claiming that your decision not to vaccinate does not impact anyone else in society.

Elaine

That still does not explain how R>1 can rise to R=1

R decreases as the number of susceptible people in the population decreases. It doesn't necessarily stop when it equals 1.

Obviously it doesnt rise if you're going from more than 1 to less than 1. I think bm wrote that by mistake?

Bruffin "Most people reading that would have the common sense to realise that 95% is not an all or nothing figure. "
That's one person here, then, with no common sense, I am afraid.

Tabutha
Are you still saying that there is no effect on disease transmission if vaccination rates are 90% as opposed to 95%?

Even bm has realised that there is an effect.

If people are so confident that vaccination works, why are you worried about whether or not other people are vaccinated??? surely you should be protected by said vaccination? herd immunity is shown time and time again to be a complete myth - outbreaks of disease occur in fully vaccinated communities.

Oh dear, someone's been drinking the crankosphere kool aid.

Have you actually read this thread and the links on it?