Zubaida Baba Ibrahim and Chioma Nnamani (Lead writers)
Vaccination remains one of the most effective ways to protect children and communities from deadly diseases, however in Nigeria too many children remain unvaccinated. Even before the COVID-19 pandemic placed additional strain on health systems, the country faced persistent challenges with low routine immunisation coverage. This uneven access continues to leave countless children vulnerable to illnesses that are entirely preventable.
The low coverage has been linked to several underlying issues, including weak supply chains, suboptimal service delivery, limited human resources, low demand driven by negative perceptions and unreliable data systems. The COVID-19 pandemic worsened the indices, pushing an additional 6.2 million children to miss routine vaccines from 2019 to 2022.
In response, global partners, including the World Health Organization (WHO), United Nations Children’s Fund (UNICEF), Gavi, the Vaccine Alliance and other health organisations launched “The Big Catch-up” a coordinated global initiative to rapidly increase immunisation coverage in 20 countries where most zero-dose children reside.
In Nigeria, the Federal and State Ministries of Health began to work closely with the relevant stakeholders to strengthen the healthcare workforce, improve immunisation delivery systems and foster demand for vaccines within communities. Weeks after the launch in 2023, Dr Faisal Shuaib, the former Executive Secretary of National Primary Health Care Development Agency (NPHCDA), explained that the goal was to reduce the number of zero-dose children in Nigeria by 15% by 2024, and 80% by the end of 2028.
However, two years have passed since the launch of “The Big Catch-Up” in Nigeria. The pressing question remains: what progress has been made?
The journey from launch to implementation
An Assistant Director in NPHCDA shares insight into the design and implementation of Nigeria’s Big Catch-Up programme. Officially launched in April 2023, the programme started by targeting 200 out of 774 local government areas (LGAs) across Nigeria, these were LGAs with an alarmingly high rate of zero dose and under immunised children, he explained.
Mapping and data driven analysis carried out by the University of Southampton guided the selection of the LGAs, while the Federal Government of Nigeria reviewed and approved the final list.
According to him, the goal was to find and vaccinate children between 12–59 months who had missed routine immunisation or had never received a single vaccine dose. Children of zero to 11 months who fell under this category continued to receive vaccine under the regular National Immunisation Schedule while the Big Catch-Up was designed to focus on older children within the selected LGAs.
In addition to this, health authorities identified another 100 LGAs in northern Nigeria that accounted for approximately 1.5 million zero-dose children. Although these LGAs were not part of the big catch up, they were reached through intensified routine immunisation efforts under Nigeria’s 2022–2025 Immunisation Recovery Plan, developed by the NPHCDA with support from WHO and UNICEF. This addition provided an opportunity to extend immunisation services to communities that would have been overlooked.
To enable thorough planning and targeted delivery, the catch up was implemented in three phases. According to the Assistant Director, Phase 1 ran from December 2024 to January 2025; Phase 2 began in February 2025 and Phase 3 started in April 2025.
While campaign timing varied by state, all the mapped-out areas were eventually reached including the Federal Capital Territory (FCT) which faced delays due to a health workers’ strike. The third phase of implementation in the FCT officially commenced on June 18, 2025.
Because reaching zero-dose children requires locating them and implementing appropriate community engagement strategies — especially because most of these communities are either remote, affected by insecurity or cut off from basic health services — the LGAs were grouped into three categories based on their accessibility, with a unique approach applied to each.
– Fully accessible (88 LGAs): In these LGAs, health workers relied on existing systems and data to Identify, Enumerate, and Vaccinate (IEV). High-burden settlements were mapped to nearby health facilities, zero-dose children were listed using electronic tools, and vaccination delivered through fixed, outreach, and mobile teams
– Partially accessible (94 LGAs): Reaching Every Settlement (RES) strategy was deployed, and this strategy involved a hit and run approach where local vigilantes, Civilian Joint Task Force (CJTF) and military personnels were deployed to support the vaccination team. Secure areas followed the IEV model, while insecure settlements relied on locally recruited teams backed by community leaders for a safe vaccination process.
– Inaccessible (19 LGAs): Reaching Inaccessible Children (RIC) Strategy was deployed in these 19 LGAs and it involved using military and specialised escorts to deliver vaccines in security-compromised areas.
The Catch-Up also focused on four lifesaving vaccines for children aged 12 to 59 months: Pentavalent vaccine, Pneumococcal Conjugate Vaccine (PCV), Inactivated Polio Vaccine (IPV) and Bivalent Oral Polio Vaccine (bOPV).
Children who had never been vaccinated, even up to age 4, were started on Penta 1, and those who could not receive all the required doses during the campaign period were directed to the nearest health facilities to continue and complete their immunisation doses.
Persisting gaps and delays
However, the implementation process has encountered a few challenges. One of which was the delay in the release of funds. Although financial support from WHO and UNICEF was available at the national level; funds could not be released to the states until certain criteria were met.
This included submission of detailed plans outlining the number of community mobilisers, vaccinators, verifiable designations, logistical arrangements, and official start dates. Some states struggled to provide these, and it slowed down the release of funds from NPHCDA during the first phase.
In addition, a significant number of health workers were unable to carry out their responsibilities due to knowledge gaps. Although they were initially trained virtually, this proved inadequate as many struggled to understand the procedures through virtual sessions alone and had to be retrained in person, leading to delays during early stages of implementation.
These challenges were addressed before the second phase commenced. Health workers were retrained through in-person sessions, and this improved their understanding and performance. Also, states that experienced funding delays streamlined their processes and became more familiar with the documentation modalities. This caused a huge improvement in coordination and ensured smoother operation in subsequent phases of the campaign.
Updates from other countries
Last year, a few countries shared updates on their progress, renewing hope in the goal of the initiative to leave no child behind. In Syria, nearly 15,000 health workers and vaccinators were deployed across more than 1,000 sites to assess children’s vaccination status and immunise those who had not yet received their shots.
In Somalia, the government applied for and received approval to access measles vaccines, IPVs, and Diphtheria, Tetanus and Pertussis (DTP) Vaccine to help close some of the country’s most pressing vaccine gaps.
In an exclusive interview with Nigeria Health Watch, Dr. Ephraim T. Lemango, UNICEF’s Associate Director of Immunisation, noted that there has been some recorded recovery largely driven by bigger countries such as India, Indonesia, Brazil and Tanzania. This has contributed to a significant global drop in the number of zero-dose children from approximately 18 million in 2021 to 14 million in 2022.