Immunization
Immunization is one of the main annual parameters collected by most DSS sites. Data collection on immunization usually takes place annually during a specific update round and is collected on children usually up to age 2 years. This age is as of the year of interview (if the child is alive) or year of death (if the child is dead). This means that you will compute current age (for surviving children) or age at death (for children who died) using the years for these events, not the exact dates. Listing of all eligible children for whom vaccination forms to be filled are produced and given for field workers to collect the information on an Immunization Form. In addition immunization forms for eligible children who are recently registered during the round (either through the in-migration form, the pregnancy outcome form, or the missed out persons/households tools) should be completed. When a vaccination card (or another written record) is available, the appropriate information from the vaccination card (or the written record) should be transferred onto the vaccination form. It is always imperative to know the recommended ages for each vaccination.
On the Immunization Form, the basic demographic information on each child is provided. A question on whether the child has a vaccination card is asked. Where the child has a card, the immunization dates on the card are transcribed onto the immunization form.  Vaccination data collected should include all vaccines given by the system and usually include BCG (Baccile Calmette Guerin), DPT/Pentavalent (Diphtheria, Pertussis, Tetanus, H Influenza Type B, and Hepatitis B),  Polio, Yellow Fever and Measles. Observing for a BCG scar is also done.  
There are instances where there may be inconsistencies with the dates. This happens when a previous date is different from the current date for the same vaccine. Another source of error is when a vaccination date is earlier than the date of birth of child and this needs to be checked and corrected. When such errors occur, a supervisor visits those households to reconcile the dates and the correction is effected on the immunization form before data entry takes place. If the inconsistency/error is not detected at the field level, it is detected at data entry and a query comes out for reconciliation.