EventRep: Overview of Polio Outbreak Response (OBR)
A MicroBiotic EventRep Publication

Circulating vaccine-derived poliovirus (cVDPV) events and outbreaks are uncommon but emerge when the weakened strain of the poliovirus contained in the oral polio vaccine (OPV) circulates in under-immunised populations over a long period of time. If enough children are not immunised against polio, the weakened virus can spread between individuals and over time, can revert to a form that can cause paralysis. 

To better address existing cVDPV transmission, and prevent future outbreaks, a strategy has been developed which includes the introduction of the novel oral polio vaccine type 2 (nOPV2), which is expected to be effective in preventing the paralytic disease and less likely to revert to neurovirulence. 

In Nigeria, an outbreak of Polio across a section of the country will initiate an outbreak response (OBR) across affected States and their neighbouring states by the National Primary Health Care Development Agency (NPHCDA). This response is always in terms of vaccination through oral droplets of nOPV2 for children under-5. Partners such as World Health Organisation (WHO), African Field Epidemiology Network (AFENET) and State Primary Health Care Development Agency (SPHCDA) also deploy their members and staff for support, supervision and monitoring.

MicroBiotics usually participates through its Chief Research and Communication Officer (CRCO), Tayo Fasuan, as an Ad Hoc Management Support Team (MST) member for AFENET in Southwestern States of Nigeria along with other ad hoc and AFENET graduates MSTs, whom would be deployed to all local government areas of the particular states where such intervention is to be implemented. 

He provides insights into how the activity is usually carried out, and below is his EventRep.

Local Government Settings

Immunisation activities are usually implemented within local governments for easy supervision and monitoring. Local governments in Nigeria usually have a minimum of eleven (11) wards, and each ward has at least one of basic, comprehensive or primary health centres, whose activities are overseen by the Officer-In-Charge (OIC) and coordinated by the Primary Health Center at the Local Government Headquarters.

Hierarchy of Vaccination Leadership

The vaccination process is carried out by many three-member teams consisting of a supervisor, a vaccinator and a mobiliser. In each ward, the activities of these teams are coordinated by the Ward Focal Persons (WFPs). In the local government just like every other local government, the overall vaccination activity was coordinated by the Local Immunisation Officer (LIO) and others such as the Cold Chain Officer (CCO), Health Educator, Local Government Disease Surveillance and Notification Officer (DSNO)  and State Technical Facilitator (STF), who all participate in monitoring, supportive supervision and conflict resolutions.

State office of WHO also provides independent monitors and supervisors to monitor and sanction incompetence and errors, while AFENET provides MSTs to primarily provide supportive supervision to the teams on the field, and also monitor as well.

The Vaccination Pre-implementation Exercise

The pre- implementation exercise for the immunisation programme starts with training. All components and individuals involved in the entire process are trained (or re-trained), including the independent monitors, MSTs and the health workers. This is achieved by organising refresher training periods for everyone by their individual organisations and bodies.

Training is usually followed or accompanied by making sure that items and conditions needed for the implementation are already available. Just like the training, these pre-implementation activities are carried out in the local government areas. 

These include social mobilisation to inform communities and their leaders and other interest groups; development of high risk operational plans to cover special places such as hard-to-reach areas and security-compromised areas; development of logistic funds distribution plan template; microplan update to reflect new communities, and; border synchronisation plans for LGAs sharing borders with neighbouring states.

The Vaccination implementation Exercise

The implementation exercise starts by deploying teams to their respective wards, and as stated earlier, each team has a supervisor, vaccinator and mobiliser. The supervisor is saddled with leading the team to follow their microplans, marking houses which have been attended to, recording immunised children, non-compliance cases and missed children and revisit cases on the tally sheet and other sheets for data and action taking. 

The vaccinator is to vaccinate the children properly, maintain hygienic practices when vaccinating, maintain cold-chain in the Vaccine Carrier Box and observe the vaccine vial monitor (VVM) periodically. The mobiliser, who is expected to be living in the community under intervention, is mainly saddled with seeking out eligible children within the community, asking vital key questions about the households and being the first in line to educate and resolve cases of non-compliance.

All members of the team work synergistically though, with some of them working together and carrying out one another’s activities except vaccination.

The Supervision and Monitoring Exercise

Supervision and monitoring of the vaccination exercise and the teams are carried out independently and jointly by the teams of SPHCDA, WHO, LGA, AFENET and NPHCDA. 

The SPHCDA team includes the State Health Educator, State Immunisation Officer (SIO), State Epidemiologist State DSNO and State Technical Facilitators (STFs) to each LGA. The LGA teams include the LIO, CCO, DSNOs, Resident Medical Officers (RMOs), and WFPs. The WHO teams include the Independent Monitors (IMs) and Supervisors, while a single AFENET/NPHCDA MST is deployed to each LGA as well. Most supervisions are in the form of supportive supervisions in order to ensure proper vaccination protocols are observed. 

The implementation activities to monitor include the following:

  • Adherence to daily work plan.
  • Presence of underage members and mobilisers in the team.
  • Status of the vaccine via the VVM and knowledge of the team about it.
  • Systematic entering of households and asking of the key questions.
  • House marking method.
  • Recording of immunised and missed children.
  • Cases of non-compliance and revisits.
  • Monitoring of Acute Flaccid Paralysis in the community (AFP).
  • Disbursement of logistic and transportation funds.
  • Provision of items such as marker pens, chalks, PPEs.
  • Vaccinator’s efficiency and expertise, and adherence to good hygienic practice.
  • Routine immunisation compliance and acceptance in the community.

Most of these monitoring and supervision are also carried out using mobile apps referred to as ODK. According to Google “Open Data Kit (ODK) is an open-source suite of tools that allows data collection using Android mobile devices and data submission to an online server, even without an Internet connection or mobile carrier service at the time of data collection. Streamline the data collection process with ODK Collect by replacing traditional paper forms with electronic forms that allow text, numeric data, GPS, photo, video, barcodes, and audio uploads to an online server.”

ODK provides a form of grading and assessment for the teams to rate their works, but corrective measures are to be provided on the spot if the implementation is not going according to the standard procedure. 

Review meetings are held daily at the LGA and State levels to discuss coverages, data, happenings and events for the daily vaccination exercises among the LGA teams, partners teams and WFPs, and corrective measures are provided to fix issues and make the next day’s work easier.

Common Occurrences During OBR (And Associated Terms)

nOPV2: This stands for novel oral polio vaccine type 2 (nOPV2). The vaccine is a modified version of the existing type 2 monovalent OPV (mOPV2), that clinical trials have shown provides comparable protection against poliovirus while being more genetically stable and less likely to revert into a form which can cause paralysis. To better address the evolving risk of type 2 circulating vaccine-derived poliovirus (cVDPV2), the Clobal Polio Eradicating Initiatives (GPEI) partners worked to deploy this additional innovative tool. The vaccine’s increased genetic stability means there is a reduced risk of seeding new cVDPV2 emergences compared to mOPV2.

Eligible Children, Missed Children: Children under 5 years old are deemed eligible for the immunisation exercise, and those who couldn’t be immunised during the vaccination intervention are termed missed children.

Adverse event following immunisation (AEFI): According to WHO, “AEFI is any untoward medical occurrence which follows immunisation and which does not necessarily have a causal relationship with the usage of the vaccine. If not rapidly and effectively dealt with, can undermine confidence in a vaccine and ultimately have dramatic consequences for immunisation coverage and disease incidence. Alternatively, vaccine-associated adverse events may affect healthy individuals and should be promptly identified to allow additional research and appropriate action to take place.” AEFI are to be promptly reported in order to be treated.

Non-compliance (NC): Non-compliance occurs when the parent(s) or caregiver(s) of an eligible child refuse to allow the child to be vaccinated. A lot of reasons can be responsible for this, which include fear of vaccines and/or AEFI, religious/cultural beliefs, unavailability of pluses (items given to children in past vaccination exercise to make them corporate) and just deliberate uncooperative attitude. Team supervisors are usually the first line of people who should try to resolve NCs, and if unresolved, should be escalated to the WFP, and finally to the LGA team, especially the Health Educator. Most times, the monitoring teams from partners are also called to help resolve NCs. Most NCs can be resolved through familiarity with the health workers and in-depth education before subtle pressure and coercion is used. Some non-compliance cases are valid however, especially for children who are very ill or non-eligible.

Vaccine Vial Monitor (VVM): According to WHO, “VVMs are small indicators that adhere to vaccine vials and change colour as the vaccine is exposed to cumulative heat, letting health workers know whether the vaccine has exceeded a pre-set limit beyond which the vaccine should not be used.”

Revisits: When a household that is known or suspected to have eligible children are met empty, then a revisit is planned either for the evening or the next day. Revisits are usually done and resolved at the start of each day before proceeding to the work plan for that particular day. Revisit cases are usually mistaken for non-compliance cases most times as both are somehow interwoven.

House-marking: Once a living building is reached, the number of households within the building is first identified before vaccination is attempted. A household can be deemed eligible or non-eligible if there are children under-5 living there or not respectively. It can also be deemed as a revisit case if eligible children are suspected or known to be living there but are not available as at the time of visit. And finally, a household can be deemed non-compliant if an eligible child is known to be there and seen, but the caregiver or parent refused immunisation. This information, together with team code, present day of vaccination, month and year of intervention and numbers of households are incorporated and written on the building. It is not a welcome process in most communities however, as many house owners frown upon the use of chalk to mark and disfigure their houses.

Hard-to-reach areas: There are some areas within most LGAs where, due to the topography and amenities like good roads, vaccination activities are very difficult to get to. They may also include areas that are security compromised due to being far away from the main community or being in areas of conflicts. Special plans are usually made for these places to be covered in conjunction with partners, security operatives and prominent members of the community or ward.

Six Key Questions: These questions are used during house-to-house vaccination exercise to ensure adequate and effective immunisation. These questions include (1) How many households (mothers) are in the building? (2) How many children are under-5? (3) How many of these children are receiving OPV for the first time? (4) Is there any child sleeping, sick or absent for other reasons? (5) Are the children being taking for routine immunisation for other diseases? (6) Is there any child who was healthy before but suddenly develop paralysis (loss of limb activities)?

Mop-up Exercise: Mop-up exercises are carried out on the very last day of the entire intervention campaign, after all the communities in the work plans have been covered. They are usually done to identify missed children, resolve revisits and deal with non-compliances.

Failed OBR: After the end of the intervention, which usually takes five days, monitors from independent groups will carry out a survey of the vaccination exercise by randomly going through each local government. A local government is said to have failed if up to ten (10) eligible children were discovered to have been unvaccinated. 

Additional Information from:
World Health Organisation.
Special Thanks to:
Bosede Alowooye, State Epidemiologist, Ministry of Health and Human Services, Ekiti State.
Kayode Ojo, State Coordinator, Neglected Tropical Diseases, Ministry of Health and Human Services, Ekiti State.