Two teens bought a cake to thank their mum for having them vaccinated.

Cake

Cake

Alyssa Jackson and her sister Ashley picked up a cake at Dairy Queen in Pittsburgh that read ''Thx 4 vaccinating us, Mom'' after thought of a tongue-in-cheek way to show their genuine gratefulness to their mother.

Alyssa told InsideEdition: ''We had just finished picking up my vaccination records from the doctor when we stopped at Dairy Queen and got food. While sitting there we made the decision to get the cake, and we wanted to write something on it.

''We wrote the thank you for vaccinations because that is a big topic right now in the media, and we do appreciate her for getting us vaccinated.''

They wrote the message on themselves because they thought it would be an odd request for the bakery.