The World Health Organization declared the recent spread of polio to be a health emergency of international concern on Monday, following the virus' recent transmission from Pakistan, Cameroon, and Syria to other states in Africa and the Middle East after being pushed to the edge of eradication several years ago. The WHO recommended that these three countries see that all of their residents and long-term visitors do not leave the country without receiving the polio vaccine. Countries where the virus has been seen but has not spread from — Afghanistan, Equatorial Guinea, Ethiopia, Iraq, Israel, Somalia, and Nigeria — are recommended to encourage those leaving the country to also receive the vaccine.