Figure 1.

Histogram of bOPV pSIAs in the 720 model subpopulations with intensification *. Abbreviations: bOPV, bivalent OPV, pSIA, preventive supplemental immunization activity. * Pakistan and Afghanistan 6 pSIAs (low coverage areas 7 pSIAs), most of the Democratic Republic of the Congo, Nigeria, and Ethiopia 2–3 pSIAs (low coverage areas 4–7 pSIAs), most of India 3 pSIAs (high-risk areas, including UP and Bihar, 5–7 pSIAs), most of Somalia and South Sudan 2 pSIAs (low-coverage areas 7 pSIAs), most of Ukraine 4 pSIAs (high-risk areas 6 pSIAs), Yemen and Papua New Guinea 6 pSIAs, most of Indonesia 1 pSIA (low coverage areas 3–4 pSIAs), most of the Syrian Arab Republic 1 pSIA (low coverage areas 2–3 pSIAs), most of Bangladesh 3 pSIAs (low coverage areas 5 pSIAs), Côte d’Ivoire, Mauritania, Egypt, and Haiti 4 pSIAs, Philippines 3 pSIAs, 3–4 pSIAs in low-coverage areas in modeled subpopulations that include countries such as: Albania, Algeria, Angola, Armenia, Azerbaijan, Benin, Bosnia and Herzegovina, Botswana, Burkina Faso, Burundi, Cambodia, Cameroon, Central African Republic, Chad, Comoros, Congo, Djibouti, Dominican Republic, El Salvador, Equatorial Guinea, Eritrea, Eswatini, Ethiopia, Gabon, Gambia, Georgia, Ghana, Guatemala, Guinea, Guinea-Bissau, Haiti, Honduras, Kazakhstan, Kyrgyzstan, Kenya, Lao People’s Democratic Republic, Lesotho, Liberia, Libya, Madagascar, Malawi, Mali, Mauritius, Montenegro, Morocco, Mozambique, Myanmar, Namibia, Nicaragua, Niger, Papua New Guinea, Philippines, Republic of Moldova, Rwanda, Senegal, Serbia, Sierra Leone, Somalia, State of Palestine, Sudan, Tajikistan, The Former Yugoslavian Republic of Macedonia, Togo, Tunisia, Turkmenistan, Uganda, Ukraine, United Republic of Tanzania, Viet Nam, Zambia, and Zimbabwe. The global model includes some of these countries due to risks posed by other countries in the same block. Generally, countries with WPV1 R₀ ≥ 10 with any levels of coverage would likely benefit from some pSIAs (e.g., the inclusion of pSIAs in India and Bangladesh), and all countries with subpopulations with coverage less than <60% would likely need 3–4 pSIAs. The model does not provide refined estimates of the number of pSIAs and may not fully account for differential decreases in coverage that occurred during COVID-19 and persist in some countries.