Vaccine-Preventable Diseases & Immunology Flashcards
7 cards from real APHA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Vaccine-Preventable Diseases & Immunology flashcards as text
Which hepatitis virus is transmitted primarily through the fecal-oral route and does NOT cause chronic infection?
Answer: Hepatitis A
Hepatitis A virus is transmitted via contaminated food and water (fecal-oral route) and causes only acute infection, never progressing to chronic hepatitis.
In the context of immunology, what does 'seroconversion' mean?
Answer: The development of detectable antibodies in serum following vaccination or infection
Seroconversion refers to the point at which detectable antibodies against a specific antigen first appear in a person's serum, indicating a successful immune response.
Haemophilus influenzae type b (Hib) most commonly causes which serious invasive disease in unvaccinated young children?
Answer: Bacterial meningitis
Before Hib vaccination, H. influenzae type b was the leading cause of bacterial meningitis in children under 5, along with epiglottitis, pneumonia, and septic arthritis.
The polysaccharide capsule of Streptococcus pneumoniae is important in vaccine development because it:
Answer: Allows the bacterium to evade phagocytosis and serves as the target antigen in vaccines
The polysaccharide capsule prevents phagocytosis, making it a key virulence factor; pneumococcal vaccines target capsular polysaccharides to generate protective antibodies.
Which statement best describes the concept of 'original antigenic sin' in immunology?
Answer: Prior exposure to an antigen shapes future immune responses, sometimes to the detriment of responses to related antigens
Original antigenic sin describes how the immune system preferentially recalls responses to previously encountered antigens, which may impair optimal responses to related but distinct antigens encountered later.
Meningococcal disease caused by Neisseria meningitidis is particularly dangerous because:
Answer: It can progress from onset to death within 24–48 hours and causes septicemia with characteristic petechial rash
Meningococcal disease is a medical emergency that can cause death within 24–48 hours due to fulminant septicemia, often presenting with a characteristic non-blanching petechial or purpuric rash.
Tetanus toxoid works as a vaccine by:
Answer: Stimulating antibody production against the tetanospasmin toxin, neutralizing it before it binds nerve tissue
Tetanus toxoid is a chemically inactivated form of tetanospasmin that induces the production of antitoxin antibodies capable of neutralizing the toxin before it irreversibly binds to nerve terminals.