The effect of the COVID-19 pandemic on routine immunization services in Sierra Leone, 2021

Kassim Kamara^1,2, Haurace Nyandemoh³, Umaru Sesay^1,2, Adel Hussein Elduma^1,2, Godfrey Kayita², Gebrekrstos Negash Gebru^1,2

 

¹Sierra Leone Field Epidemiology Training Program, Freetown, Sierra Leone, ²African Field Epidemiology Network (AFENET), Freetown, Sierra Leone, ³Expanded program on immunization (EPI), Ministry of Health, Freetown, Sierra Leone

 

 

^&Corresponding author
Gebrekrstos Negash Gebru, Sierra Leone Field Epidemiology Training Program, African Field Epidemiology Network (AFENET), Freetown Sierra Leone.

 

 

 

 

One of the main public health achievements in 21st-century is the development, deployment, and implementation of vaccines and immunization programs [1]. Over the past couple of decades, immunization programs have become an important means of disease control and are considered the most cost-effective public health intervention, averting an estimated 3.5 to 5 million deaths every year worldwide [2]. Immunization services are part of routine primary health care in most countries across the world, as part of the expanded program on immunization (EPI).

 

In 1978, Sierra Leone established the EPI on a small scale as a major public health strategy that provides an opportunity for children to access life-saving vaccines to reduce susceptibility to vaccine-preventable diseases (VPD) and reducing infant mortality rates [3].

 

By the 1980s, Sierra Leone had expanded access on the EPI program from one vaccine to seven vaccines. However, the 11-year civil war which ended in 2002 destroyed the health care infrastructure and workforce capacity built. The Government of Sierra Leone has undertaken several measures to rebuild the health care system to increase the efficiency and productivity of the health care service delivery system, consequently reducing the high morbidity and mortality of children and women of childbearing age. In 2010, the government introduced a free healthcare initiative targeting vulnerable populations seeking healthcare services, mainly children under five years old, pregnant women, and breastfeeding mothers [4].

 

Between 2006 to 2018, the EPI program introduced additional vaccines to provide six life saving vaccines namely: BCG, oral polio vaccines (OPV), pentavalent, pneumococcal conjugate vaccine, rotavirus, inactivated polio vaccines (IPV), measles-rubella (MR), and, yellow fever. Consequently, the uptake of vaccines improved significantly. For instance, DPT3 (Diphtheria, pertussis, tetanus) pentavalent immunization coverage increased approximately from 38% in 2001 to 98% in 2014. However, this progress was severely interrupted by the catastrophic Ebola outbreak in 2014/2015, which claimed the lives of more than 10,000 Sierra Leoneans [5].

 

Following the Ebola outbreak, the Government with the support of its development and implementation health partners enacted recovery measures to improve EPI Programming which improved the performance of routine immunization services. For example, the coverage rate of Penta 3 increased from 86% in 2015 to 96.2% in 2019, rotavirus vaccine coverage increased from 85% in 2015 to 92% in 2019 [6].

 

The EPI in Sierra Leone targets ten vaccine-preventable diseases in children less than one year of age, plus neonatal tetanus through immunization of pregnant women. According to the World Health Organization (WHO) and United Nations Children's Fund (UNICEF), despite improvements in childhood vaccination globally, about 23 million children missed out on essential vaccines through routine immunization services programming in 2020, the highest since 2009 and 3.7 million more than in 2019 [7].

 

In March 2020, Sierra Leone recorded its first case of coronavirus disease 2019 (COVID-19) after the WHO declared COVID-19 an international public health emergency [8]. The Government then prioritized the response to COVID-19 by diverting financial and human resources from other essential health services. Thus, basic health services were interrupted leading to frequent outbreaks such as measles and vaccine-derived poliovirus type two. Anecdotal reports indicate COVID-19 had negatively affected routine immunization services in Sierra Leone. However, there is limited information on the effect of COVID-19 on routine immunization coverage in Sierra Leone. We conducted this study to assess the effect of COVID-19 on routine immunization coverage to ascertain the magnitude of the effect and recommend mitigation strategies. The findings of this study will be extrapolated to provide information on the effects of epidemics/pandemics, including COVID-19 and Ebola on routine immunization services and give recommendations to minimize these effects in the future.

 

 

Study design and period

 

We conducted a descriptive study using secondary EPI data from the Sierra Leone health management information system (HMIS) for four-years (2018 to 2021) during the period of September 2021 to January 2022.

 

Study area and population

 

Sierra Leone is a country located on the West Coast of Africa with a population of 7,548,702 people [9]. The country is comprised of 16 districts, including the capital of Freetown, which is located in the Western Area Urban District [10]. The country´s health infrastructure is tiered with over 1,307 public and private health facilities. Routine immunization services are provided in all health facilities and delivered in three modes: static, mobile, and outreach. Infants who survive their first year of life, make up 3.7% of the total population (study population).

 

Data source

 

The source of data for this study was the Health Management Information System. The Health Management Information System (HMIS) database was launched in 2012, but its operation was also severely hampered by the Ebola outbreak. Following the Ebola outbreak, which highlighted the gap in data collection, dissemination, and reporting, all health facilities were mandated to report health data, including aggregated routine immunization through the HMIS for routine immunization conducted monthly. To enhance the quality of data stored in the HMIS, health authorities within the Ministry of Health (MoH) with support from partners conduct regular data quality assessments. HMIS data is owned by the MoH and the system is supported by Oslo University. This system is used by 80 low and middle income countries and by more than 100 countries, globally[11].

 

The routine immunization data uploaded in this system is aggregated and provides health authorities with insights into monitoring the trend and pattern of health conditions, the impact of interventions, and, ultimately, a guide on the appropriate resource allocation. Possible bias in secondary data analysis included prior knowledge of the data, pre-registered analysis if it is appropriate for the data, and lack of flexibility in the data. To minimize these biases, we checked data distribution and missing variables, planned for the data analysis before accessing the data, and conducted prior analysis before extracting the data. We used data from this system because it is the main system for storing all health data and used for decision making.

 

Data collection

 

We extracted the vaccination data from the health management information system (HMIS), on the numbers of pentavalent immunizations (Penta1 and Penta3) and MR 1 and 2 doses administered for the period under study. We also generated the 2015 national population census data from the Statistic Sierra Leone website to account for our denominator.

 

Pre-COVID-19 pandemic and COVID-19 pandemic eras

 

The Sierra Leone pre-COVID-19 pandemic era was before the country recorded its first case on 30 March 2020, that is, 2018 to 2019. During this era, childhood vaccinations were conducted through routine and supplemental immunizations with limited challenges. However, following the COVID-19 outbreak and the introduction of COVID-19 vaccines in the country, the Ministry of Health experienced many challenges including refusals due to persistent rumors of the normal childhood vaccines being that of COVID-19 vaccines.

 

Data management and analysis

 

The data downloaded from the HMIS system was stored in Microsoft Excel 2016. Records with two or more missing data were excluded from the study. Rough and clean data were password protected to ensure data security and confidentiality. The variables selected and analyzed were vaccination coverages and dropout rates for measles rubella (MR) 1 and 2, and pentavalent (Penta 1 and 3). We analyzed the data using MS Excel 2016. We calculated the vaccination coverage for the above-mentioned antigens considering the following parameters; total number of vaccinated children divided by the target population and multiplied by 100. The dropout rate was computed by comparing the number of children who started the immunization schedule with the number of the same children who completed it. We presented the findings in proportions, graphs, and tables. To determine whether the coverage of an antigen is high or low, we used the national coverage of 95% and the WHO coverage of 90%. The national target dropout rate is <10%.

 

Ethical considerations

 

Permission for this study was obtained from the EPI program and the Directorate of Health Security and Emergencies of the Ministry of Health. Proper data handling and storage of source documents including password protection for the computer used to manage the data. The results of the analysis were only shared with authorized stakeholders and organizations.

 

 

From 2018 to 2019, the national coverages of Penta1 and Penta3 increased from 93.9% to 96.2%, and from 90.6% to 96.2%, respectively. From 2020 to 2021, Penta1 and Penta3 national coverages decreased from 93.3% to 75.5% and from 91.3% to 74. 4%, respectively, indicating 17.8% and 16.9% drop in the coverage on Penta 1 and Penta 3, respectively. This drop in the coverages could lead to increased child morbidity and mortality. Before the COVID-19 outbreak in Sierra Leone, ten of the 16 districts had consistently achieved their targets for Penta3 coverage but only four districts achieved their targets since the outbreak of COVID-19 in the country. The country achieved the MR1 coverage target only in 2019 with 93.8%, but the coverage declined drastically in 2021 to 71.5%. The target for MR2 coverage was not achieved for all three years (Figure 1).

 

Also, Measles Rubella2 coverage was not achieved in all four years with the lowest vaccination coverage of 53.8% recorded in 2021 (Figure 2). The dropout rate for Penta1 and Penta3 was within the acceptable less than 10% rate throughout the study period. The dropout rate for MR1 and MR2 exceeded the acceptable target of less than 10% throughout the study period (Figure 3).

 

Six districts met the target for Penta 1 and only four districts met the Penta 3 target as shown in Table 1. In 2021, ten Districts achieved the 90% WHO target vaccination coverage for Penta 1 while only eight eight districts achieved the target for Penta 3. Moyamba District consistently exceeded the 90% WHO target for both Penta 1 and Penta 3 coverage throughout the study period. However, Bombali District, followed by Western Area Urban, consistently failed to achieve both the national 95% and WHO 90% throughout the study period (Table 1).

 

Ten Districts experienced a drop in MR 1 coverage in 2020 compared with the period before the COVID-19 outbreak in the country. Furthermore, except for the Pujehun District with 97.2% coverage for MR1, no District achieved the WHO target coverage of 90% in 2020. For MR 2, only Moyamba District met the target with 99.1% vaccination coverage in 2019. In 2020 and 2021, none of the Districts achieved the WHO target of 90% vaccination coverage for MR 2 (Table 2).

 

 

Immunization programs continue to be affected negatively by epidemics and pandemics, globally. This negative effect often results in disease outbreaks, increased morbidity, and high mortality among under-five children [12-14].

 

The main finding of this study was that routine immunization was affected negatively by the COVID-19 pandemic in Sierra Leone. The finding that Penta 1 and Penta 3 vaccination coverage increased from 2018 to 2019 but dropped during the COVID-19 pandemic period of 2020 and 2021 could be attributed to the disruption of immunization activities, and vaccine hesitancy exacerbated by the pandemic. In a study conducted in Rwanda, all maternal and child health services were disrupted by the COVID-19 pandemic, including vaccination [15]. However, even before the COVID-19 pandemic, the country did not meet the Penta 1 and Penta 3 WHO 90% coverage target. This could be attributed to systemic factors such as under estimated target population, shortage of vaccines, and access to health facilities. The drop in the vaccination coverage in Penta 1 and Penta 3 can increase the incidence of childhood diseases such as tetanus, whooping cough, hepatitis B, and diphtheria. The drop in the coverage of these vaccines could lead to more morbidity among children from vaccine preventable diseases such as tenanus, whooping cough among others [16-18].

 

High vaccination coverage of Measles and Rubella is critical for the prevention of measles outbreaks and congenital Rubella syndrome among pregnant women [19]. The finding that Sierra Leone failed to achieve MR1 coverage except in 2019 and never achieved MR2 coverage for all the years under review is worrisome. This low vaccination coverage of MR1 and MR2 might be responsible for the recent measles outbreaks in almost all districts in the country [20]. The low uptake of MR particularly the MR2 vaccine, could be because the majority of mothers in Sierra Leone have limited knowledge on when to seek MR2 vaccination compared to the second dose of other vaccines like pentavalent[21]. Similar to Measles, congenital Rubella syndrome cases may increase with low MR coverage [22]. Similar to Sierra Leone, the COVID-19 pandemic has affected other countries in Africa with low MR vaccination coverage with similar increase in vaccine preventable diseases [23-27].

 

Based on our findings, Sierra Leone has achieved the targeted dropout rate for Pentavalent, which is considered a positive indicator. However, the MR dropout rate target was not achieved before and during the COVID-19 outbreak. Our findings showed that MR vaccination coverage was low before the COVID-19 pandemic. This finding necessitates the EPI program to prioritize the improvement of MR vaccination in the country. The finding revealed that the Western Area Urban District consistently failed to achieve MR vaccination coverage throughout the study period. This suggests that strategies to improve MR vaccination coverage in WAU are urgently needed. This low vaccination coverage might be attributed to an unstable population, poor planning, and hesitancy of the Western Area Urban population to uptake vaccines. Also, because WAU was the first district to record COVID-19 cases, the government of Sierra Leone imposed prolonged restriction measures to halt the spread of the virus to other districts. Therefore, this low vaccination coverage might be attributed to COVID-19 lockdown which led to disruption in the supply and distribution due to travel restrictions. Although all sixteen districts are expected to meet the target of all antigens, it is encouraging to observe that on average six districts achieved the vaccination coverage of Penta 1 and Penta 3. According to the findings of this study, Pujehun district was the only district to meet the MR target during the first year of the pandemic. This could be because the district health management team sought assistance from various health partners within the district, such as funds, logistics, and human capacity, to carry out COVID-19 sensitization activities. These initiatives might have increased the use of routine vaccines. Finally, this study revealed that COVID-19 had a negative effect routine immunization coverage in Sierra Leone which could be one of the outbreak of vaccine preventable diseases such as measles. The main strength of this study is that it uses national data that represents all sixteen districts of Sierra Leone. Because of this, decision-making by health authorities will be adequately informed. Despite this strength, this study has several limitations. Because the routine immunization data uploaded to the HMIS is aggregated, this study was unable to determine the sex or age group most affected, as well as whether a specific child experienced delays in accessing routine vaccines during the pandemic. Timeliness and completeness of the data may have affected the accuracy of the data analyzed. Over reporting and under reporting of the data to justify performance or lack of resources is another limitation of this study.

 

 

COVID-19 had a negative impact on the Expanded Program on Immunization services in Sierra Leone. We observed a decrease in vaccination coverage for Pentavalent and measles Rubella and an increase in the dropout rate for Measles/Rubella. This drop in coverage and the rise in dropout rates during the pandemic have made children more susceptible to vaccine-prevenatable diseases, possibly leading to a parallel outbreak of measles. We recommend that the EPI program strengthen vaccination indicators and increase community awareness on the importance, availability, and timeliness of immunization activities. Additionally, we advise that the Ministry of Health to prioritize districts with low vaccination uptake when conducting a mass immunization campaign during and after the pandemic.

 

 

The authors declare no competing interests.

 

 

Data collection: Haurace Nyandemoh. Study design: Kasssim Kamara, Haurace Nyandemoh, Umaru Sesay, Adel Hussein Elduma, Gebrekrstos Negash Gebru. Data analysis: Kasssim Kamara, Haurace Nyandemoh, Umaru Sesay, Adel Hussein Elduma, Gebrekrstos Negash Gebru. Writing: Kasssim Kamara, Haurace Nyandemoh, Umaru Sesay, Adel Hussein Elduma. Revision and final approval: Adel Hussein Elduma, Gebrekrstos Negash Gebru.

 

 

We would like to acknowledge the Ministry of Health for permitting us to use the data.

 

 

Table 1: Penta1 and Penta3 vaccination coverages by Districts, Sierra Leone 2018 - 2021

Table 2: Measles Rubella1 and Measles Rubella2 vaccination coverages by Districts, Sierra Leone 2018 - 2021

Figure 1: Penta1 and Penta3 coverages by year, Sierra Leone, 2018-2021

Figure 2: Measles Rubella1 and 2 coverages by year, Sierra Leone, 2018-2021

Figure 3: Penta1 and 3 and MeaslesRubella1 and 2 dropout rates by year, Sierra Leone, 2018-2021

 

 

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