Immunisation coverage and factors associated with incomplete immunisation in children under two during the COVID-19 pandemic in Sierra Leone

Abstract

Background Routine childhood immunisation is one of the most important life-saving public health interventions. However, many children still have inadequate access to these vaccines and millions remain (partially) unvaccinated globally. As the COVID-19 pandemic disrupted health systems worldwide, its effects on immunisation have become apparent. This study aimed to estimate routine immunisation coverage among children under two in Sierra Leone and to identify factors associated with incomplete immunisation during the COVID-19 pandemic. Methods A cross-sectional household survey was conducted in three districts in Sierra Leone: Bombali, Tonkolili and Port Loko. A three-stage cluster sampling method was followed to enrol children aged 10–23 months. Information regarding immunisation status was based on vaccination cards or caretaker’s recall. Using WHO’s definition, a fully immunised child received one BCG dose, three oral polio vaccine doses, three pentavalent vaccine doses and one measles-containing vaccine dose. Following the national schedule, full immunisation status can be achieved at 9 months of age. Data were weighted to reflect the survey’s sampling design. Associations between incomplete immunisation and sociodemographic characteristics were assessed through multivariable logistic regression. Results A total of 720 children were enrolled between November and December 2021. Full vaccination coverage was estimated at 65.8% (95% CI 60.3%-71.0%). Coverage estimates were highest for vaccines administered at birth and decreased with doses administered subsequently. Adjusting for age, the lowest estimated coverage was 40.7% (95% CI 34.5%-47.2%) for the second dose of the measles-containing vaccine. Factors found to be associated with incomplete immunisation status were: living in Port Loko district (aOR = 3.47, 95% CI = 2.00-6.06; p-value < 0.001), the interviewed caretaker being Muslim (aOR = 1.94, 95% CI = 1.25–3.02; p-value = 0.015) and the interviewed caretaker being male (aOR = 1.93, 95% CI = 1.03–3.59, p-value = 0.039). Conclusion Though full immunisation coverage at district level improved compared with pre-pandemic district estimates from 2019, around one in three surveyed children had missed at least one basic routine vaccination and over half of eligible children had not received the recommended two doses of a measles-containing vaccine. These findings highlight the need to strengthen health systems to improve vaccination uptake in Sierra Leone, and to further explore barriers that may jeopardise equitable access to these life-saving interventions.

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“…9 This is consistent with a recent study on immunisation in Sierra Leone, which saw a higher likelihood of missed vaccination for children with Muslim caregivers compared to children with Christian caregivers. 26 While these findings might not be consistent with all Muslims, it is believed that vaccine hesitancy and rejection among Muslims might be connected to whether vaccines are 'halal' (religiously permissible) or in line with Islamic teachings, particularly during the month of Ramadan. 12,[36][37][38] Previous evidence from Nigeria showed that tensions between Muslims and Christians may be a contributing factor, since vaccines mostly come from Christian nations.…”

“…25 Many children either missed out on routine vaccination or never received the recommended doses of vaccines such as meases. 26 authorities. For example, the disproportionate use of power to enforce compliance during public health responses to health emergencies has been shown to severely impact access and demand for both routine and emergency vaccines.…”

“…Wassenaar and colleagues (2024) note that children with male caregivers are likely to have lower immunisation rates, due to men's limited involvement and knowledge about childhood vaccination. 26 Understanding the dynamics of patriarchal and gender norms is essential in developing targeted interventions for men and women to enhance gender-sensitive decision making on vaccination at household and community levels. This should be coupled with programmes that seek to empower women to be able to make decisions for themselves.…”