Xavier and Yogender stay in the same hostel of same university, Xavier develops infection due to group B meningococcus. After few days , Yogender develops infection due to Group – C meningococcus. All the following are true statement except:
**Core Concept**
Meningococcal infections are caused by the bacterium Neisseria meningitidis, which has several serogroups, including A, B, C, W, and Y. The serogroups are classified based on the capsular polysaccharide present on the surface of the bacteria.
**Why the Correct Answer is Right**
The correct answer is related to the concept that individuals who have been exposed to one serogroup of Neisseria meningitidis are not necessarily protected against other serogroups. This is because the immune response is serogroup-specific, meaning that antibodies produced against one serogroup do not provide cross-protection against other serogroups. Therefore, it is possible for two individuals, like Xavier and Yogender, to develop infections caused by different serogroups of Neisseria meningitidis.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the development of infection in Yogender due to Group C meningococcus after Xavier's infection with Group B meningococcus does not necessarily imply that Yogender was exposed to Xavier's infection. Meningococcal infections can occur independently in separate individuals.
* **Option B:** This option is incorrect because the fact that Xavier and Yogender stay in the same hostel does not necessarily increase the risk of transmission of meningococcal infections between them. Meningococcal infections are primarily spread through respiratory droplets and close contact with an infected person.
* **Option C:** This option is incorrect because there is no established evidence that vaccination against one serogroup of Neisseria meningitidis provides cross-protection against other serogroups.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that serogroup-specific vaccines are available for Neisseria meningitidis, and vaccination against one serogroup does not provide protection against other serogroups.
**Correct Answer: A. This option is incorrect because the development of infection in Yogender due to Group C meningococcus after Xavier's infection with Group B meningococcus does not necessarily imply that Yogender was exposed to Xavier's infection.