Self-Assessment Questions (SAQs) for Study Session 6

Now that you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering the following questions. Write your answers in your Study Diary and discuss them with your Tutor at the next Study Support Meeting. You can check your answers with the Notes on the Self-Assessment Questions at the end of this Module.

SAQ 6.1 (tests Learning Outcomes 6.1, 6.2 and 6.3)

Which of the following statements is false? In each case, explain what is incorrect.

  • A  Vaccine Vial Monitors (VVMs) measure exposure to freezing temperatures.
  • B  It is safe to use vaccines that have reached the VVM discard point if the expiry date has not passed.
  • C  The thermometer is an instrument for measuring the temperature in a refrigerator.
  • D  Diluents should always be kept in the main refrigerator compartment.


  • A is false. The VVM records exposure of vaccines to heat over a period of time, but it does not record exposure to freezing temperatures.
  • B is false. Even if the expiry date has not passed, it is unsafe to use vaccines that have reached the discard point indicated by the VVM.
  • C is true. A thermometer measures the temperature in a refrigerator.
  • D is false. Diluents can be kept at room temperature if there is not enough space in the refrigerator, but should be chilled thoroughly before use.

SAQ 6.2 (tests Learning Outcomes 6.1, 6.2 and 6.3)

Figure 6.16 shows the VVM attached to two different vials of vaccine. Would you use the vaccines with the VVM shown below in (a) and (b)? Explain your answer.

Figure 6.16  Vaccine vial monitors (VVMs) for SAQ 6.2.


  • a.The vaccine can be used because the inner square of the VVM is lighter than the outer circle. This means that the vaccine has not been damaged by excessive heat.
  • b.This vaccine should not be used because the inner square of the VVM is almost as dark as the outer circle. This means that the vaccine has been damaged by excessive heat and should be discarded.

SAQ 6.3 (tests Learning Outcome 6.5)

Complete Table 6.1 by putting a cross in the appropriate empty column for each vaccine to show which shelf it should be stored on in a front-loading refrigerator.

Table 6.1  Storage of vaccines in a front-loading refrigerator.

VaccineTop shelfMiddle shelf
Pentavalent or DPT


The completed version of Table 6.1 appears below, with the correct shelf for storing each vaccine marked with a cross.

Table 6.1  Storage of vaccines in a front-loading refrigerator.

VaccineTop shelfMiddle shelf

SAQ 6.4 (tests Learning Outcomes 6.4 and 6.5)

On Friday, Abeba decides to defrost and clean her refrigerator because a lot of ice has collected around the freezer compartment. She puts conditioned ice-packs in a vaccine carrier and then places the vaccines from the refrigerator in the middle. There is not enough room in the vaccine carrier for everything, so she puts the diluents on the window ledge. She thought to herself: ‘The diluents will be safe here until I can put them back in the refrigerator. Diluent doesn't lose its strength as vaccine does.’

The following Monday is immunization day at the Health Post and many children come in for measles immunization. Abeba takes the measles vaccine out of the refrigerator, but at first she cannot find the diluent. Eventually she sees it on the window ledge.

  • a.Can the diluent be used to reconstitute the measles vaccine?
  • b.What should Abeba do before she can immunize the children?


  • a.Abeba must not reconstitute the vaccine using the diluent which has been on the window ledge for several days because it will be warm. Warm diluent damages the vaccine.
  • b.Abeba should put the diluent back into the refrigerator and only use it when it is cold again (between +2ºC and +8 ºC). She should apologise to the parents and explain that they can either wait for several hours for the diluent to reach the correct temperature, or come back for the next immunization session.

SAQ 6.5 (tests Learning Outcomes 6.2, 6.3, 6.4 and 6.6)

Figure 6.17 shows a dial thermometer used to measure the temperature of a vaccine refrigerator. Is this temperature safe for storing vaccines? What actions should be taken?

Figure 6.17  Refrigerator dial. (Photo: Basiro Davey)


The thermometer shows a temperature of +22oC. This is much too high a temperature for storing vaccines! They have to be stored between +2oC and +8oC. This refrigerator is not working at all and must be repaired, or the power may have been cut off. Check the gas, electricity or kerosene supply, and call your supervisor to report the problem. Move the vaccines and diluents into cold boxes and transport them quickly to the nearest health centre for cold storage.

SAQ 6.6 (tests Learning Outcomes 6.2, 6.4 and 6.5)

How do you keep the following vaccines cold during an immunization session?

  • a.Vaccine in opened vials that you are using.
  • b.Vaccine in unopened vials.


  1. Opened vials that you are using should be put on the foam pad that rests above the conditioned ice-packs on top of the vaccine carrier. Make sure that the vaccine carrier is in a shady place, not in sunshine.
  2. Unopened vials should be put inside the vaccine carrier with conditioned ice-packs or chilled water bottles and the lid closed until you need them.

SAQ 6.7 (tests Learning Outcomes 6.3, 6.4 and 6.6)

Look at the refrigerator temperature chart in Figure 6.14.

  • a.What was the temperature on the 11th day of the month, and what actions should the Health Extension Practitioner have taken on that day?
  • b.What happened on the 12th day of the month, and what actions should have been taken then?


  • a.On the morning of the 11th day of the month, the temperature of the refrigerator had risen to above +8ºC, which is above the acceptable temperature range. The refrigerator should have been checked on that day. The thermostat should have been adjusted to ‘colder’. If this action was taken, and the temperature still continued to rise, the vaccines should have been moved into a vaccine carrier and attempts made to repair the refrigerator or restore the power supply (e.g. the kerosene may have run out).
  • b.Figure 6.14 shows that the temperature continued to rise, and reached about +18ºC by the morning of the 12th of the month. This is much too high for safe storage of vaccines. It would be important to check the VVM on any vaccines which had remained in the refrigerator during this time, and throw away any which had reached their discard point.

Summary of Study Session 6