Epidemiological impact and cost-effectiveness analysis of COVID-19 vaccination in Kenya. Issue 8 (1st August 2022)

• Record Type: Journal Article
• Authors: Orangi, Stacey; Ojal, John; Brand, Samuel PC; Orlendo, Cameline; Kairu, Angela; Aziza, Rabia; Ogero, Morris; Agweyu, Ambrose; Warimwe, George M; Uyoga, Sophie; Otieno, Edward; Ochola-Oyier, Lynette I; Agoti, Charles N; Kasera, Kadondi; Amoth, Patrick; Mwangangi, Mercy; Aman, Rashid; Ng'ang'a, Wangari; Adetifa, Ifedayo MO; Scott, J Anthony G; Bejon, Philip; Keeling, Matt J; Flasche, Stefan; Nokes, D James; Barasa, Edwine
• Is Part Of: BMJ global health. Volume 7:Issue 8(2022)
• Publication Date: 2022-08-01
• Subjects: COVID-19 -- Vaccines -- Health economics -- Epidemiology; World health -- Periodicals; 362.105
• DOI: 10.1136/bmjgh-2022-009430
• Languages: English
• ISSNs: 2059-7908

Abstract

Abstract : Background: A few studies have assessed the epidemiological impact and the cost-effectiveness of COVID-19 vaccines in settings where most of the population had been exposed to SARS-CoV-2 infection. Methods: We conducted a cost-effectiveness analysis of COVID-19 vaccine in Kenya from a societal perspective over a 1.5-year time frame. An age-structured transmission model assumed at least 80% of the population to have prior natural immunity when an immune escape variant was introduced. We examine the effect of slow (18 months) or rapid (6 months) vaccine roll-out with vaccine coverage of 30%, 50% or 70% of the adult (>18 years) population prioritising roll-out in those over 50-years (80% uptake in all scenarios). Cost data were obtained from primary analyses. We assumed vaccine procurement at US$7 per dose and vaccine delivery costs of US$3.90–US$6.11 per dose. The cost-effectiveness threshold was US$919.11. Findings: Slow roll-out at 30% coverage largely targets those over 50 years and resulted in 54% fewer deaths (8132 (7914–8373)) than no vaccination and was cost saving (incremental cost-effectiveness ratio, ICER=US$−1343 (US$−1345 to US$−1341) per disability-adjusted life-year, DALY averted). Increasing coverage to 50% and 70%, further reduced deaths by 12% (810 (757–872) and 5% (282 (251–317) but was not cost-effective, using Kenya's cost-effectiveness threshold (US$919.11). Rapid roll-out with 30% coverage averted 63% more deaths and was more cost-saving (ICER=US$−1607 (US$−1609 to US$−1604) per DALY averted) compared with slow roll-out at the same coverage level, but 50% and 70% coverage scenarios were not cost-effective. Interpretation: With prior exposure partially protecting much of the Kenyan population, vaccination of young adults may no longer be cost-effective.