Which of the following is a live attenuated vaccine?
- A.Tetanus toxoid
- B.Oral polio vaccine
- C.Rabies vaccine
- D.Hepatitis B vaccine
Correct answer
Explanation
The correct answer is B, the oral polio vaccine, which contains live poliovirus weakened so that it can multiply in the gut and raise immunity without causing the disease; it is the vaccine given as two drops in the pulse polio rounds. Option A, tetanus toxoid, is not a germ at all but the toxin of the tetanus bacterium inactivated by chemical treatment, so it belongs to the toxoid class along with diphtheria. Option C, the rabies vaccine in use today, contains virus grown in cell culture and then killed, so it is an inactivated vaccine, and this option is the commonest mistake because Pasteur's original preparation was a weakened one. Option D, the hepatitis B vaccine, carries only the surface protein of the virus, made by recombinant yeast, so it is a subunit vaccine. BCG and the measles-rubella vaccine are the other live attenuated examples.
Read the full article: Blood Groups, Immunity and Vaccines: Notes for Exams
Practice Questions
View allWho discovered the ABO system of blood groups?
- A.Karl Landsteiner
- B.William Harvey
- C.Edward Jenner
- D.Alexander Fleming
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The correct answer is A, Karl Landsteiner, the Austrian physician who found in 1900 that human blood falls into groups according to the antigens on the red cells, which made safe transfusion possible, and who received the Nobel Prize in Physiology or Medicine for it in 1930; with Wiener he…
Read the full explanation →Which blood group is called the universal donor?
- A.A
- B.B
- C.AB
- D.O
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The red cells of group O carry neither the A antigen nor the B antigen, so when they are transfused the antibodies in the recipient's plasma find nothing to bind to and the cells are not destroyed, which is why group O, and strictly O negative, can be given to…
Read the full explanation →A person of which blood group has no antibody in the plasma and is therefore the universal recipient?
- A.O
- B.A
- C.B
- D.AB
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A person of group AB carries both the A and the B antigen on the red cells, and because the body does not make antibodies against its own antigens, the plasma carries neither anti-A nor anti-B; blood of any group can therefore be transfused into such a person, who is…
Read the full explanation →The Rh factor in human blood is named after
- A.a rhesus monkey
- B.a rabbit
- C.a river in Europe
- D.the scientist Rh. Weber
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Landsteiner and Wiener found the antigen in 1940 while working with the blood of the rhesus monkey, and the first two letters of rhesus gave the factor its name; a person with the D antigen on the red cells is Rh positive and one without it is Rh negative.
Read the full explanation →Which vitamin is essential for the clotting of blood?
- A.Vitamin A
- B.Vitamin C
- C.Vitamin D
- D.Vitamin K
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The liver needs vitamin K to make prothrombin and several other clotting factors, so a deficiency of it lengthens the clotting time and causes bleeding; this is why a newborn is given vitamin K and why the vitamin is sometimes called the anti-haemorrhagic vitamin.
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