Data from the United Nation Children Emergency Fund (UNICEF) and World Health Organization (WHO) show that 23 million children were unvaccinated or under-vaccinated in the year 2020, which was 4 million higher than 2019 figures. Of those 23 million children, more than 60 percent live in just 10 countries (India, Nigeria, the Democratic Republic of the Congo, Pakistan, Indonesia, Ethiopia, Brazil, Philippines, Angola and Mexico) and 17 million of them were zero-dose children (UNICEF, 2020).

By definition, a vaccine-preventable disease (VPD) is an infectious disease for which an effective vaccine already exists. Any death occurring as a result of a VPD is referred to as a vaccine-preventable death. VPDs can spread through several routes such as air, body contact and respiratory droplets (WHO, 2020). Vaccines are among the greatest advances in global health and over the past two decades, have helped reduce the scourge of preventable diseases like polio, measles, whooping cough and smallpox (UNICEF, 2018).

COVID-19 (also called SARS-CoV-2) was first discovered in Wuhan, China in December, 2019. Contrary to previous concerns, the virus was not genetically engineered and neither was it a biological weapon developed in a laboratory (Anderson et al., 2020). Like many other respiratory viruses, COVID-19 is spread through infected droplets which are projected from the mouth or nose when the infected person speaks, coughs, sneezes or breathes. COVID-19 affects the respiratory system and can feel like a common cold or pneumonia although its effects are not limited to the respiratory system alone. According to the WHO, there have been 528,816,317 cases of COVID-19 globally, with 6,294,969 confirmed deaths as at the 1st of June, 2022.

The COVID-19 pandemic caused an increased disruption of essential services, particularly during the lockdown period put in place by most countries (Nigeria inclusive) to curb the spread of the virus. The height of the pandemic greatly exposed the vulnerability of health service delivery systems, particularly existing immunization systems worldwide. Essential services such as routine immunization were affected partially due to the diversion of healthcare funding and resources towards tackling the pandemic. Research published in the Lancet also indicate that there was a decline in the number of administered doses of Diphtheria-Pertussis-Tetanus (DPT3) vaccine and first dose of Measles-containing vaccine (MCV1) in the first half of 2020, particularly in the WHO Africa region (Shet et al., 2022). 

The disruptions to immunization services due to the pandemic were attributed to several factors including; 

1. General hesitancy to seek medical services for fear of contracting the virus 

2. Changes in health-seeking behaviors due to the strict requirements for social distancing and  lockdown procedures

3. Diversion of health personnel and resources towards emergency pandemic preparedness and control. 

These factors had a significant impact on immunization services with a subsequent increased risk of VPD resurgence (Ota et al., 2021), especially in low and middle-income countries (LMIC) such as Nigeria. These LMICs also reported an increased number of unvaccinated infants and young children (Shet et al., 2022). In a separate research conducted by the pediatric association of Nigeria to assess the impact of COVID-19 on immunization coverage in Nigeria, the findings showed that there was a 70% drop in children’s immunization services in 2020 compared to the previous year. A total absence of outreach services and campaigns, limited fixed immunization sessions, general drop in the number of immunized children and pockets of disease outbreaks all over the country were also reported (Tagbo et al., 2020).

The “Health Service Uptake during COVID-19” (HUC) dashboard owned by the Nigerian Federal Ministry of Health (accessible here), provides insights into the immunization status of children in Nigeria. This tool is a part of the Multi-Source Data Analytics and Triangulation platform (MSDAT) which can be accessed here. The data obtained from the HUC dashboard helps provide vital information as to the effects of the COVID-19 pandemic on health service delivery, including immunization activities in Nigeria.

Fig 1: Fully immunized children less than 1 year of age (Source; the MSDAT)

With regards to figure 1 above, there was an overall decrease in the number of fully immunized children aged 0 to 12 months since the lockdown measures were initiated in the year 2020, compared to the year 2019. May 2020 showed the biggest drop in immunization with only 360,112 children being immunized, an approximately 20% drop from the corresponding month in 2019 where over 450,000 children were immunized.

Similarly, the figures for 2021 were lower than the figures of the year 2019. This was the recognized trend for most states in Nigeria. The first quarter in 2022, although inconclusive, points towards a steady progress in immunization status of children compared to 2021 and 2020 respectively.

Fig 2: Comparison of Immunization status by program area (Source; the MSDAT)

Comparing the National immunization coverage for Measles vaccine and Penta 1 vaccine as against < 1 year fully immunized children, May 2020 (which essentially was the height of COVID-19 lockdown) recorded the lowest turnout for immunization in the years under review. There appears to be a steady increase in immunization coverage in 2021 and 2022; although these indicators are yet to return to the levels recorded in the year 2019.

Fig 3: comparison of National < 1 year immunization status for three selected states (Source; the MSDAT)

The under-1 year immunization status for three selected states in the North, West and South (those with high population estimates) were compared in Figure 3 above. In Lagos state, immunization coverage dropped significantly in 2020 but it appears that in the following year, the immunization records matched figures of 2019 while 2022 has seen a better record so far. In Kano state, the immunization coverage remained fairly stable throughout the post lockdown period with the current year 2022 indicating better outcomes. For Rivers state, the figure above clearly indicates that immunization efforts during and post pandemic (with the exception of March 2022) have failed to match the records achieved in the year 2019. The reason for this could possibly be due to Rivers state having lots of communities in hard to reach areas which, coupled with the lockdown, could have massively hindered accessibility to health facilities by parents or caregivers.

Lessons learnt from the coronavirus pandemic

The Nigerian Center for Disease Control (NCDC) estimates that over 3,143 deaths have occurred from an estimated 256,148 cases so far (at the time of this publication). The outbreak of COVID-19 has impacted several aspects of Nigeria’s healthcare system, resulting in; 

1. Overwhelming the health facilities and staff

2. Inability for parents and caregivers to access health facilities.

3. Reduction in funding for core service delivery activities; as more resources are directed towards outbreak control.

4. Decline in economic outcomes, particularly during the lockdown that followed.

Recommended guidelines by the WHO for immunization services during the COVID-19 pandemic

1. Improvement in the health system including routine immunization: the ability of Nigeria to prevent, detect and respond to outbreaks of VPDs depends on the strengthening of her health system. Improved funding, political backing, strategic health planning and emergency preparedness will ensure that the country is better equipped to tackle outbreaks in the future without halting or limiting the provision of other essential services such as routine immunization.

2. Capacity building of current health workers on the recommended guidelines for maintaining childhood immunizations during the COVID-19 pandemic such as; ensuring that scheduled appointments for routine childhood immunizations are not deferred or canceled and to prioritize newborn care as well as vaccination of young children (0-24 months)

3. Full immunization of health workers because they serve as a firewall to prevent the spread of the virus.

4. Improving the working conditions of health workers may also help mitigate the brain drain currently experienced in the healthcare sector. This will also motivate healthcare workers to avail themselves at the health facilities regardless of the pandemic.

5. Effective public health communications through awareness campaigns to the grassroots. This will help calm any nerves or mistrust by the host communities as regards the vaccination of children.

6. Infectious disease surveillance for better outbreak detection and control.


Vaccines work to reduce the burden of diseases. Possible outbreaks of VPDs amidst the global pandemic need to be addressed critically as data from the HUC dashboard shows that in general, the number of fully immunized children (under the age of 1) dropped following the COVID-19 pandemic. This drop could be attributed to the subsequent lockdown imposed by the federal government of Nigeria as a means to contain the spread of COVID-19, among other things.


1. More effort (including optimizing outreach sessions) needs to be put in place to ensure that the pandemic and other efforts to curtail its spread, does not limit the provision and access to vaccines for children in Nigeria.

2. It would be necessary to implement mechanisms that ensure adherence to the stipulated WHO guidelines for immunization services during the global pandemic.

3. Expand on the immunization coverage targets on immunization plans; to address drop out rates or those children previously missed due to the COVID-19 pandemic.


Andersen, K.G., Rambaut, A., Lipkin, W.I. et al., 2020 The proximal origin of SARS-CoV-2. Nat Med 26, 450–452. 

Anita Shet, Kelly Carr, Carolina Danovaro-Holliday, Samir V Sodha et al., 2022. Impact of the SARS-CoV-2 pandemic on routine immunization services: evidence of disruption and recovery from 170 countries and territories. The Lancet Global Health Series.

Federal ministry of health, health service uptake during covid19. Available

Ota, M., Badur, S., Romano-Mazzotti, L., & Friedland, L. R. (2021). Impact of COVID-19 pandemic on routine immunization. Annals of medicine, 53(1), 2286–2297.

Tagbo, B. N., Alikor, E. A. D., Ogunrinde, G. O., Tabansi, P., Nwaneri, D. U., 2020. Impact of COVID-19 pandemic on immunization services in Nigeria; A preliminary report by Pediatric Association of Nigeria (PAN). Niger. j. paediatr; 47(3): 288-295.

The Center for disease control (CDC), 2019. Available 

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WHO, 2020. International travel and health: vaccine-preventable diseases and vaccines (2019 update). Available