UNICEF delivered vaccines for over 600,000 North Korean children and pregnant women this week, the organization announced on Thursday, while urging Pyongyang to let U.N. aid workers back into the country.

The agency delivered over “four million doses” of a wide variety of vaccines via chartered flights on Monday, Tuesday and Thursday, according to a press release from the U.N. organization.  

Breakdown of shipments:

• 680,000 doses of Bacille Calmette-Guerin vaccine
• 309,500 doses of Hepatitis B vaccine
• 1,339,000 doses of Measles-Rubella vaccine
• 291,400 doses of Pentavalent vaccine
• 1,092,000 doses of Tetanus-diphtheria vaccine
• 495,600 doses of Inactivated Polio Vaccine 

The DPRK’s health