Immunization Programme Related Terms

EPI: Expanded Programme on Immunization

CHD: Child Health Division. It is one of the divisions of Department of health services, Nepal. It is responsible to carry out the programmes related to child health in the country.

Immunization: Immunization is a process through which one is made immune to or resistant against some infectious disease, typically by vaccination. For example: when a child is given oral polio, the child will become immune to wild polio as the polio vaccine induces immune reactions and build up antibodies against wild polio.

Vaccine Wastage Rate: Wastage is often defined as “loss by use, decay, erosion, or leakage or through wastefulness”. It is essential to understand the vaccine usage to understand about vaccine wastage. Vaccine usage is defined as the proportion of vaccine administered against vaccine issued.  Usually vaccines are issued with expected vaccine wastage.  Vaccine wastage is the opposite of vaccine usage. Thus, the Vaccine Wastage Rate can be defined as 100 minus the vaccine usage rate. Total Vaccine wastage and the total vaccine usage gives total no. of vaccines issued.

Vaccine wastage can primarily be divided into two categories of: (1) wastage in unopened vials; (2) wastage in opened vials.

Multi dose vial: One vial may contain such amount that is adequate for more than one person. For example, one vial of measles vaccine contains amount that is adequate for 5 people, vial of DPT, Hep B, TT contains vaccine for 10 doses and One OPV vial is enough for 20 doses.

Vaccine Vial Monitor (VVM): It is simply a label, which contains heat sensitive material placed on a vaccine vial. This label is an indicator to monitor whether the vaccines are kept in the recommended temperature. If the vaccines are exposed in the heat, the label changes the color indicating ineffectiveness of the vaccine. The white square inside the purple circle as shown in the picture below is the vaccine vial monitor. The material in the white square is heat sensitive and this starts to change over time if the vial is not placed in the appropriate temperature. 

Bacillus calmatte Guerin (BCG): It is a vaccine given immediately birth of a baby upto one month. This vaccine is given against the disease tuberculosis. This vaccine contains live attenuated pathogens so this shouldn’t be given to children or adults, who are immune-compromised. For example, if a child is born with HIV, he/she shouldn’t be vaccinated with BCG. This is also contraindicated in Pregnancy.

Oral Polio vaccine (OPV): Oral Polio vaccine is given against the disease poliomyelitis. This also contains weakened strains of polio virus, which induces immune reaction and help in forming antibodies agains poliomyelitis. This is given at 6, 10, 14 weeks of age. For more information: https://publichealthinnepal.blogspot.com/2016/04/future-no-oral-polio-vaccine-in-nepal.html

Measles vaccine: this is given against the viral disease Measles at the age of 9 months. However, this is rarely given alone. Nowadays, measles vaccine is replaced with MR vaccine that against both measles and Rubella. Rubella acts against viral disease Rubella. This is recommended at the age of 9 months and second dose at the age of 15 months.

DPTHephib: This is a pentavalent vaccine. D stands for Diphtheria, P for Pertusis, T for tetanus, Hep for Hepatitis B, HIB: Haemophilus influenza B. this is a combination vaccine, which develops immunity against all these aforementioned diseases. Previously, only DPT was included in our immunization programme, however, later Hepatitis B vaccine and then HIB is added in this combo vaccine. Three doses are recommended at the age of 6, 10 and 14 weeks of age.

Inactivated Polio vaccine(IPV): This is given against Poliomyelitis at the age of 14 weeks. https://publichealthinnepal.blogspot.com/2016/04/future-no-oral-polio-vaccine-in-nepal.html

PCV or Pneumococcal conjugate Vaccine: This vaccine is added in our National Immunization Programme since 2015. This vaccine helps in developing immunity against the disease pneumonia, one of the leading causes of child mortality in Nepal. One of the other severe forms of pneumococcal disease is meningitis causing life-long disability such as hearing loss and learning disability.

Adverse Event Following Immunization (AEFI): Even though vaccines are safe and are administered after testing its safety and efficacy, some might suffer adverse events following immunization. Adverse event following immunization is any untoward medical occurrence which follows immunization and which may not always have a causal relationship with the usage of the vaccine. This needs to be identified whether the adverse event is caused by vaccine as this might affect immunization coverage and disease incidence.

There is a surveillance system for monitoring adverse events following vaccination. The AEFI surveillance system started in Nepal in 2004 with 31 sentinel sites.