6.2 Needs estimation

6.2.1 Vaccines

Number of vaccines

The vaccine needs (Appendix 18) are estimated based on:

• The target population (age group to be vaccinated)
• The objective (100% in an epidemic situation)
• The wastage rate, estimated at 15%; 100 doses are needed to vaccinate 85 people (15% wastage means that 117 doses need to be ordered to vaccinate 100 people, or a wastage factor of 1.17)
• The buffer stock: estimated to be from 10 to 25% (depending on the number of people to be vaccinated and the reliability of the population figures)

Example: to vaccinate all children aged 6 months - 15 years in a total population of 50,000, calculate the number of vaccine doses to order as follows:

To prevent errors due to different vaccine presentations, always express needs as the number of doses and not the number of vials (that is, 1,000 doses, not 100 vials).

Vaccine storage volume

When planning, always consider the volume taken up by:

• Vaccines: for cold chain storage needs
• Diluents: they take up the same volume as vaccines, but do not go into the cold chain until 12 to 24 hours before use

Presentations may vary. The average volume per vaccine dose can range from 2 to 4 cm³ (for 5- to 10-dose vials). Verify the volume with the suppliers or via the WHO website [1]Citation 1.World Health Organization. Prequalified Vaccines. WHO - Prequalification of Medical Products (IVDs, Medicines, Vaccines and Immunization Devices, Vector Control). 
https://extranet.who.int/prequal/vaccines/prequalified-vaccines

Example: a box of fifty 10-dose vials (500 doses) of lyophilised vaccine takes up a total of 18.6 cm x 9.8 cm x 5.8 cm = 1,057 cm³. Thus, the volume taken up per dose is 2.1 cm³ (1,057/500)

6.2.2 Medical supplies

Injection supplies

• Injection supply needs are based on the number of vaccine doses needed (Appendix 18).
• Count 1 dilution syringe and needle per vial.
• Use only auto-disable syringes (ADS) to administer the vaccine. Allow 5 to 10% wastage  due to handling errors.

Other supplies

• 500 g of cotton wool for every 500 vaccinations.
• To collect used syringes/needles, use 15-litre safety boxes (about 400 syringes), rather than 5-litre safety boxes (about 100 syringes), if possible.
• Alcohol-based solution, handwashing supplies, etc.

In sparsely populated areas where fewer people are vaccinated each day, the safety boxes will only be partially filled, so allow for more safety boxes (15% more, for example) for a rural vaccination campaign.

6.2.3 Cold chain

Needs

Needs in terms of the active cold chain (which makes things cold) and the passive cold chain (which keeps them cold) are estimated based on:

• The volume of vaccines to be stored in the refrigerator (expressed in liters)
• The freezing capacity (in kg/24 hours) and storage volume needed for the ice packs
• The vaccination schedule
• The cold chain equipment needed at each vaccination site and the maximum number of sites that will be operating simultaneously
• The cold chain equipment needed for each supervision team and the maximum number of supervision teams working simultaneously
• Existing cold chain equipment available for the campaign

New INDIGO® equipment: a new backpack-style vaccine carrier that does not require ice packs is now available. Its net volume is 1.8 litres aCitation a.The net volume is 2L according to the manufacturer. The useful volume is 1.8L for vaccine vials and the cold 
chain monitoring card. . At an ambient temperature of 43°C without opening it has a cold life of 5 days, after which it requires a 3-hour recharge with a special electric charger. It can be used in many situations and is particularly well-suited for mobile teams.

Inventory of available equipment

While a cold chain sometimes needs to be set up quickly from scratch, equipment is often available locally and simply needs to be supplemented. Inventory the equipment available at the various levels before ordering. Verify that the equipment is actually in place and works.

Refrigerators: check the available capacities and specify the model, brand, number and energy type. Consider and evaluate other available refrigeration options, such as a partner’s cold room. Verify that the equipment has WHO pre-qualification (Prequalified Quality System) to ensure good performance.

Freezers: check the available capacities and specify the model, brand, number and energy type. Consider and evaluate other available freezing options, such as renting or borrowing equipment, or places that make ice (fisheries, businesses, markets, ice cream manufacturers, etc.). WHO prequalification is not necessary when choosing freezers for ice packs, but choose equipment known for high quality, if possible.

Electrical systems: check the reliability, accessibility, quality, and security. Check the power and voltage and any potential fluctuations during the day.

Generators: Draw up a list of available equipment and indicate which type of fuel it uses (e.g. petrol or diesel)

Cold boxes, vaccine carriers and ice packs: get an inventory of existing equipment at each health care facility. Verify the condition and indicate the type, brand and model and how many there are. Be sure to specify the number of ice packs by volume (0.3-litre, 0.4-litre or 0.6-litre).

Cold chain monitoring equipment: thermometers, twice-daily monitoring sheets, LogTag®, etc.

See Appendix 19, 20, 21 and 22.

Cold chain for teams/vaccination sites

Correct storage during transport and at vaccination sites is essential to ensure vaccine quality.

Campaigns require large amounts of ice. The total number of ice packs needed per day is calculated based on the vaccination and supervision team needs (Appendix 23):

• For one fixed-site vaccination team:
  • One RCW25 cold box for storing vaccines and diluents (one cold box may be enough if two teams work at the same site)
  • One vaccine carrier for intermediate storage of vaccines and diluents
• For one supervision team: one cold box (spare vaccines and diluents).

• For one mobile team: if access is difficult, using no-ice vaccine carriers with a long cold life like the Indigo® vaccine carrier (See above) can be helpful.

  Note: The Indigo® vaccine carrier takes at least 3 hours to charge with a special charger, and the system is expensive compared to conventional vaccine carriers.

To allow rotation (using/freezing), double the number of ice packs needed per cold box and vaccine carrier.

For calculating storage volume: one frozen 0.6-litre ice pack takes up about 1 litre. Estimate the 
total storage volume needed and the freezing capacity (in kg/day) so that there are enough ice packs on the first day of the campaign to ensure a continuous supply for the entire campaign. Always add a 10 to 20% safety margin, or even more, depending on the context.

6.2.4 Vaccination kit

The kit- and module-based supply system simplifies needs calculation and procurement. All of the materials needed are delivered at the same time.

The KMEDKIMM3-- kit (Appendix 24) allows set-up of an emergency vaccination campaign for 10,000 people with 5 vaccination teams. The kit contains medical and logistics modules.

It can be ordered complete or by module, depending on the strategy chosen, the human resources available and local constraints and resources.

6.2.5 Data collection tools

The data collection system should be in place before the campaign begins. The main data entry tools are prepared and the staff trained in their use.

Vaccination card

The vaccination card should include, at least, the last name, first name, age and address of the person vaccinated and the vaccination date. Other information is sometimes requested, such as lot number, vaccine name, sex, vitamin A, etc.

The vaccination card is the only proof of vaccination and should be kept. Different models may be used:

• National immunisation programme card: in this case, make sure that the dose administered during the campaign is clearly identified (specific box or stamp indicating the vaccine and the date).
• Card specific to the current vaccination campaign (Appendix 25). This should be as simple as possible.

Daily tally sheet

This is used to keep a count of the day’s activity (Appendix 26). The recorder checks off each dose administered by age group (e.g. 6-8 months, 9-11 months, 12-59 months or 5-15 years).

This sheet should also include:

• The vaccination location, site and date
• The team identifier (for later verification, if needed)
• The number of vaccine and diluent vials received and the lot numbers (for traceability in case there is a problem)
• The supplies received and remaining at the end of the day (for estimating the supplies used)
• The status of the vaccine vial monitors (VVMs) at the end of the day

Summary sheets and summary table

Using the tally sheets from the vaccination teams, supervisors compile the data by day or by location on the summary sheets (Appendix 27) analyse them, and implement the appropriate corrective measures with their team.

At the end of the campaign the summary table is used to analyse the results and draft the final report.