Every year WHO and UNICEF review available data on national immunization coverage and make country-specific estimates of immunization coverage.

These estimates are based on data officially reported to WHO and UNICEF by Member States as well as data reported in the published and grey literature in 2020. Whenever possible we have consulted with local experts - primarily national EPI managers and WHO regional office staff - for additional information regarding the performance of specific local immunization services. Based on the data available, consideration of potential biases, and contributions from local experts, we have attempted to determine the most likely true level of immunization coverage in each country.

The 2020 estimates are based on data reported until 6 July 2021. Exceptionally, 2020 estimates were not made for 35 countries, since they had no reported data. Time series will be updated later in the year if countries submit their reported data.