« Folate | Main | Cardiac screening of footballers »

Friday, October 26, 2018

Comments

Sawyer

Why did vaccine use to be useless?

edmund

'Useless' is obviously a bit sweeping. Vaccine efficacy is judged by comparing the attack rate- i.e. people who get the target disease -in vaccinated people or groups versus the attack rate in non-vaccinated. Measles vaccine is at the top of the range - about 95% protective efficacy. Typhoid is much lower (don't know the exact number).
As to why measles vaccine is effective and the old typhoid vaccine much less so: I don't really know but the most likely is that the vaccine simply didn't provoke enough antibody response in recipients.
Some vaccines (e.g. influenza and malaria) lack efficacy because the target keeps changing but I don't think that applies to typhoid.

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Working...
Your comment could not be posted. Error type:
Your comment has been saved. Comments are moderated and will not appear until approved by the author. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.

Working...

Post a comment

Comments are moderated, and will not appear until the author has approved them.

Your Information

(Name and email address are required. Email address will not be displayed with the comment.)