Private hospitals have to place orders for vaccines on CoWin and cannot directly procure it from manufacturers, July 1 onwards. The Centre has also devised a formula to decide the 'maximum monthly limit' of stocks that a private vaccination centre can purchase to ensure a level-playing field.Private hospitals have to place orders for vaccines on CoWin and cannot directly procure it from manufacturers, July 1 onwards. The Centre has also devised a formula to decide the 'maximum monthly limit' of stocks that a private vaccination centre can purchase to ensure a level-playing field.