Table 1.
Clinical and economic outcomes of different COVID-19 vaccination program strategies of vaccine supply and vaccination pace under different scenarios of epidemic growth in South Africa.
| Scenario and Vaccination Strategy | Cumulative SARS-CoV-2 infections | Cumulative COVID-19 deaths | Years-of-life lost | Health care costs, USD | ICER, USD per year-of-life saveda |
|---|---|---|---|---|---|
|
| |||||
| Vaccine supply | |||||
|
| |||||
| Re = 1.4 | |||||
| Vaccine supply 40% | 11,784,700 | 16,000 | 275,800 | 1,177,742,900 | -- |
| Vaccine supply 67% | 10,585,100 | 14,700 | 259,600 | 1,338,803,500 | Dominated |
| Vaccine supply 80%b | 10,410,000 | 12,000 | 217,900 | 1,425,272,800 | 4,270 |
| Vaccine supply 20% | 15,489,500 | 21,800 | 397,300 | 1,508,890,800 | Dominated |
| No vaccination | 21,012,100 | 89,300 | 1,558,700 | 1,766,856,200 | Dominated |
| Two-wave epidemicc | |||||
| Vaccine supply 40% | 7,758,800 | 10,600 | 175,100 | 927,247,000 | -- |
| Vaccine supply 67% | 5,594,000 | 7,800 | 133,700 | 1,009,741,300 | 1,990 |
| Vaccine supply 80%b | 5,940,500 | 6,900 | 119,100 | 1,047,885,500 | 2,600 |
| Vaccine supply 20% | 12,765,900 | 19,900 | 371,500 | 1,148,772,700 | Dominated |
| No vaccination | 19,290,400 | 70,400 | 1,206,200 | 1,691,805,000 | Dominated |
|
| |||||
| Vaccination pace | |||||
|
| |||||
| Re = 1.4 | |||||
| Pace 300,000 vaccinations per day | 5,659,400 | 7,200 | 120,300 | 1,016,586,100 | -- |
| Pace 200,000 vaccinations per day | 8,191,900 | 9,600 | 151,300 | 1,123,694,300 | Dominated |
| Pace 150,000 vaccinations per day | 10,585,100 | 14,700 | 259,600 | 1,338,803,500 | Dominated |
| No vaccination | 21,012,100 | 89,300 | 1,558,700 | 1,766,856,200 | Dominated |
| Two-wave epidemicc | |||||
| Pace 300,000 vaccinations per day | 2,697,100 | 3,200 | 49,300 | 780,133,600 | -- |
| Pace 200,000 vaccinations per day | 4,148,500 | 5,900 | 90,300 | 881,291,000 | Dominated |
| Pace 150,000 vaccinations per day | 5,594,000 | 7,800 | 133,700 | 1,009,741,300 | Dominated |
| No vaccination | 19,290,400 | 70,400 | 1,206,200 | 1,691,805,000 | Dominated |
|
| |||||
| Vaccine supply and vaccination pace | |||||
|
| |||||
| Re = 1.4 | |||||
| Vaccine supply 40%, pace 300,000 vaccinations per day | 9,866,800 | 13,000 | 211,300 | 969,576,100 | -- |
| Vaccine supply 67%, pace 300,000 vaccinations per day | 5,659,400 | 7,200 | 120,300 | 1,016,586,100 | 520 |
| Vaccine supply 40%, pace 150,000 vaccinations per day | 11,784,700 | 16,000 | 275,800 | 1,177,742,900 | Dominated |
| Vaccine supply 67%, pace 150,000 vaccinations per day | 10,585,100 | 14,700 | 259,600 | 1,338,803,500 | Dominated |
| No vaccination | 21,012,100 | 89,300 | 1,558,700 | 1,766,856,200 | Dominated |
| Two-wave epidemicc | |||||
| Vaccine supply 67%, pace 300,000 vaccinations per day | 2,697,100 | 3,200 | 49,300 | 780,133,600 | -- |
| Vaccine supply 40%, pace 300,000 vaccinations per day | 6,223,600 | 7,200 | 126,900 | 780,274,900 | Dominated |
| Vaccine supply 40%, pace 150,000 vaccinations per day | 7,758,800 | 10,600 | 175,100 | 927,247,000 | Dominated |
| Vaccine supply 67%, pace 150,000 vaccinations per day | 5,594,000 | 7,800 | 133,700 | 1,009,741,300 | Dominated |
| No vaccination | 19,290,400 | 70,400 | 1,206,200 | 1,691,805,000 | Dominated |
USD: United States dollars. ICER: incremental cost-effectiveness ratio. Re: effective reproduction number. Dominated: the strategy results in a higher ICER than that of a more clinically effective strategy, or the strategy results in less clinical benefit (more years-of-life lost) and higher health care costs than an alternative strategy.
Within each Re scenario, vaccination strategies are ordered from lowest to highest cost per convention of cost-effectiveness analysis. ICERs are calculated compared to the next least expensive, non-dominated strategy. Displayed life-years and costs are rounded to the nearest hundred, while ICERs are calculated based on non-rounded life-years and costs and then rounded to the nearest ten.
When modeling a vaccination program that seeks to vaccinate 80% of the population, uptake among those eligible was increased to 80% to avoid a scenario in which supply exceeds uptake. If uptake is not increased beyond 67%, then the strategy of vaccinating 67% of the population provides the most clinical benefit and results in an ICER of $9,960/YLS compared with vaccinating 40% of the population when Re is 1.4 and $1,990/YLS in an epidemic scenario with periodic surges.
In the analysis of an epidemic with periodic surges, the basic reproduction number (Ro) alternates between low and high values over time, and the Re changes day-to-day as the epidemic and vaccination program progress and there are fewer susceptible individuals. For most of the simulation horizon, Ro is 1.6 (equivalent to an initial Re of 1.1). However, during days 90–150 and 240–300 of the simulation, Ro is increased to 2.6. This results in two epidemic waves with peak Re of approximately 1.4–1.5.