HealthCareMagic is now Ask A Doctor - 24x7 | https://www.askadoctor24x7.com

Get your health question answered instantly from our pool of 18000+ doctors from over 80 specialties
159 Doctors Online

By proceeding, I accept the Terms and Conditions

Dr. Andrew Rynne
MD
Dr. Andrew Rynne

Family Physician

Exp 50 years

HCM Blog Instant Access to Doctors
HCM BlogQuestions Answered
HCM Blog Satisfaction

What Causes One To Get Typhoid Even After Getting Vaccinated?

A few years ago I got the typhoid fever shot because I was going to be traveling to some poorer countries. 1 month after I had the shot, I went on vacation and became violently ill. The doctors told me it was typhoid fever. I was tested, and I responded positively to SALMONELLA O, TYPE Vi POSITIVE A with somatic(O) antigens. My question is, how do I know for sure that I did have Typhoid fever (and that the positive test wasn't the result of my earlier vaccination)? Wasn't my vaccination supposed to prevent the Typhoid? What are the chances someone can get Typhoid even though they were vaccinated? Does this mean I can get typhoid fever again (do I need to be vaccinated again?)
Mon, 4 May 2015
Report Abuse
Internal Medicine Specialist,  's  Response
Hello,

first of all, the vaccine does not confer 100% protection, so getting sick cannot be excluded.
The diagnosis of typhoid fever is not based on a positive H and O because this test is considered obsolete. And the reason is that a patient may have other pathogens that cross-react and give positive results, so an overdiagnosis of typhoid fever would occur if we relied on this test only.

The most accurate way to establish the diagnosis is by culturing the organism. Stool cultures is the most feasible strategy but bone marrow specimen can be used as well.

The vaccine efficacy is not very well studied but it can be about 70%. It declines rapidly with time. Three years after vaccination it's supposed to be lower than 50%. If this was typhoid fever indeed then this acts as a booster for your immune system. So if you're going to travel again in the future then perhaps you should receive vaccination again, particularly if more than a couple of years have passed since the last vaccination.

Kind Regards!
I find this answer helpful

1 Doctor agrees with this answer

Note: For more detailed guidance, please consult an Internal Medicine Specialist, with your latest reports. Click here..
Disclaimer: These answers are for your information only and not intended to replace your relationship with your treating physician.
This is a short, free answer. For a more detailed, immediate answer, try our premium service [Sample answer]
Share on
 

Recent questions on Vaccine


Loading Online Doctors....
What Causes One To Get Typhoid Even After Getting Vaccinated?

Hello, first of all, the vaccine does not confer 100% protection, so getting sick cannot be excluded. The diagnosis of typhoid fever is not based on a positive H and O because this test is considered obsolete. And the reason is that a patient may have other pathogens that cross-react and give positive results, so an overdiagnosis of typhoid fever would occur if we relied on this test only. The most accurate way to establish the diagnosis is by culturing the organism. Stool cultures is the most feasible strategy but bone marrow specimen can be used as well. The vaccine efficacy is not very well studied but it can be about 70%. It declines rapidly with time. Three years after vaccination it s supposed to be lower than 50%. If this was typhoid fever indeed then this acts as a booster for your immune system. So if you re going to travel again in the future then perhaps you should receive vaccination again, particularly if more than a couple of years have passed since the last vaccination. Kind Regards!