Tracking the uptake and trajectory of COVID-19 vaccination coverage in 15 West African countries: an interim analysis

Afolabi, Muhammed O.; Wariri, Oghenebrume; Saidu, Yauba; Otu, Akaninyene; Omoleke, Semeeh Akinwale; Ebenso, Bassey; Adebiyi, A; Ooko, M; Ahinkorah, BO; Ameyaw, Edward Kwabena; Seidu, A-A; Agogo, Emmanuel; Nomhwange, Terna; Salami, Kolawole; Mohammed, N.; Yaya, Sanni

doi:10.1136/bmjgh-2021-007518

Cited by 34 publications

(24 citation statements)

References 10 publications

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“…However, with the availability of more vaccine doses, if the current vaccination rates for youths and the elderly in Model 3 are tripled, then herd immunity will be attainable in WA by the end of 2023. This result aligns with studies in [51] calling for a substantial ramp up in COVID-19 vaccination in WA to achieve herd immunity. Another issue with the vaccination program in WA is that many of the vaccines used in the area are of lower efficacy.…”

Section: Discussion Limitations and Conclusionsupporting

confidence: 89%

Impact of age-structure and vaccine prioritization on COVID-19 in West Africa

Taboe

Asare-Baah

Yesmin

et al. 2022

Preprint

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The ongoing COVID-19 pandemic has been a major global health challenge since its emergence in 2019. Contrary to early predictions that sub-Saharan Africa (SSA) would bear a disproportionate share of the burden of COVID-19 due to the region’s vulnerability to other infectious diseases, weak healthcare systems, and socioeconomic conditions, the pandemic’s effects in SSA have been very mild in comparison to other regions. Interestingly, the number of cases, hospitalizations, and disease-induced deaths in SSA remain low, despite the loose implementation of non-pharmaceutical interventions (NPIs) and the low availability and administration of vaccines. Possible explanations for this low burden include epidemiological disparities, under-reporting (due to limited testing), climatic factors, population structure, and government policy initiatives. In this study, we formulate a model framework consisting of a basic model (in which only susceptible individuals are vaccinated), a vaccine-structured model, and a hybrid vaccine-age-structured model to reflect the dynamics of COVID-19 in West Africa (WA). The framework is trained with a portion of the confirmed daily COVID-19 case data for 16 West African countries, validated with the remaining portion of the data, and used to (i) assess the effect of age structure on the incidence of COVID-19 in WA, (ii) evaluate the impact of vaccination and vaccine prioritization based on age brackets on the burden of COVID-19 in the sub-region, and (iii) explore plausible reasons for the low burden of COVID-19 in WA compared to other parts of the world. Calibration of the model parameters and global sensitivity analysis show that asymptomatic youths are the primary drivers of the pandemic in WA. Also, the basic and control reproduction numbers of the hybrid vaccine-age-structured model are smaller than those of the other two models indicating that the disease burden is overestimated in the models which do not account for age-structure. This result is also confirmed through the vaccine-derived herd immunity thresholds. In particular, a comprehensive analysis of the basic (vaccine-structured) model reveals that if 84% (73%) of the West African populace is fully immunized with the vaccines authorized for use in WA, vaccine-derived herd immunity can be achieved. This herd immunity threshold is lower (68%) for the hybrid model. Also, all three thresholds are lower (60% for the basic model, 51% for the vaccine-structured model, and 48% for the hybrid model) if vaccines of higher efficacies (e.g., the Pfizer or Moderna vaccine) are prioritized, and higher if vaccines of lower efficacy are prioritized. Simulations of the models show that controlling the COVID-19 pandemic in WA (by reducing transmission) requires a proactive approach, including prioritizing vaccination of more youths or vaccination of more youths and elderly simultaneously. Moreover, complementing vaccination with a higher level of mask compliance will improve the prospects of containing the pandemic. Additionally, simulations of the model predict another COVID-19 wave (with a smaller peak size compared to the Omicron wave) by mid-July 2022. Furthermore, the emergence of a more transmissible variant or easing the existing measures that are effective in reducing transmission will result in more devastating COVID-19 waves in the future. To conclude, accounting for age-structure is important in understanding why the burden of COVID-19 has been low in WA and sustaining the current vaccination level, complemented with the WHO recommended NPIs is critical in curbing the spread of the disease in WA.

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Section: Discussion Limitations and Conclusionsupporting

confidence: 89%

Impact of age-structure and vaccine prioritization on COVID-19 in West Africa

Taboe

Asare-Baah

Yesmin

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…However, with the availability of more vaccine doses, if the current vaccination rates for youths and the elderly in Model 3 are tripled, then herd immunity will be attainable in WA by the end of 2023. This result aligns with studies in ( Afolabi et al, 2021 ) calling for a substantial ramp up in COVID-19 vaccination in WA to achieve herd immunity. Another issue with the vaccination program in WA is that many of the vaccines used in the area are of lower efficacy.…”

Section: Discussion Limitations and Conclusionsupporting

confidence: 87%

The impact of age structure and vaccine prioritization on COVID-19 in West Africa

Taboe¹,

Asare-Baah²,

Yesmin³

et al. 2022

Infectious Disease Modelling

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“…Implementing such tools ranges from difficult to impractical for health facilities in low-and middle-income settings where human resources, medications, laboratory testing and imaging are routinely lacking with shortages expected to worsen during times of surge [3]. With the low vaccination coverage in many African countries [7], and the emergence of highly transmissible variants [8], COVID-19 may be a recurring problem for some time to come. To sustain health service delivery during the enduring pandemic, healthcare providers in sub-Saharan Africa urgently need contextually appropriate tools to identify and triage potential COVID-19 patients.…”

Section: Introductionmentioning

confidence: 99%

Implementation of a COVID-19 screening tool in a southern Nigerian tertiary health facility

Ogboghodo

Osaigbovo

Obaseki

et al. 2022

PLOS Glob Public Health

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Screening for coronavirus disease 2019 (COVID-19) in emergency rooms of health facilities during outbreaks prevents nosocomial transmission. However, effective tools adapted for use in African countries are lacking. This study appraised an indigenous screening and triage tool for COVID-19 deployed at the medical emergency room of a Nigerian tertiary facility and determined the predictors of a positive molecular diagnostic test for COVID-19. A cross-sectional study of all patients seen between May and July 2020 at the Accident and Emergency of the University of Benin Teaching Hospital was conducted. Patients with any one of the inputs- presence of COVID-19 symptoms, history of international travel, age 60 years and above, presence of comorbidities and oxygen saturation < 94%- were stratified as high-risk and subjected to molecular testing for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Data was obtained from the screening record book patterned after a modified screening tool for COVID-19, deidentified and entered into IBM-SPSS version 25.0. Binary logistic regression was conducted to determine significant predictors of a positive SARS-CoV-2 test. The level of significance was set at p < 0.05. In total, 1,624 patients were screened. Mean age (standard deviation) was 53.9±18.0 years and 651 (40.1%) were 60 years and above. One or more symptoms of COVID-19 were present in 586 (36.1%) patients. Overall, 1,116 (68.7%) patients were designated high risk and tested for SARS-CoV-2, of which 359 (32.2%) were positive. Additional inputs, besides symptoms, increased COVID-19 detection by 108%. Predictors of a positive test were elderly age [AOR = 1.545 (1.127–2.116)], co-morbidity [AOR = 1.811 (1.296–2.530)] and oxygen saturation [AOR = 3.427 (2.595–4.528)]. This protocol using additional inputs such as oxygen saturation improved upon symptoms-based screening for COVID-19. Models incorporating identified predictors will be invaluable in resource limited settings.

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Tracking the uptake and trajectory of COVID-19 vaccination coverage in 15 West African countries: an interim analysis

Cited by 34 publications

References 10 publications

Impact of age-structure and vaccine prioritization on COVID-19 in West Africa

Impact of age-structure and vaccine prioritization on COVID-19 in West Africa

The impact of age structure and vaccine prioritization on COVID-19 in West Africa

Implementation of a COVID-19 screening tool in a southern Nigerian tertiary health facility

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