Doctors Without Borders/Médecins Sans Frontières (MSF) vaccinated 710,000 people against yellow fever in 11 days in the Democratic Republic of Congo (DRC). The organizations is saying "Thank you" to all the donors and supporters of the campaign who made this possible. A vaccination campaign on this scale comes with numerous logistical challenges, such as managing the movements of 65 vehicles in densely populated neighborhoods and ensuring that the cold chain remains effective in keeping the vaccines at the proper temperature. Every day, the teams needed 4,000 ice packs and coolers in different locations. Read more about the campaign.