Saw this email at work:
I thought I’d share the process that worked for my parents. My parents received Covishield in India earlier this year and now they are in Seattle. As a first step, I reached out to my general physician to get her advice on if they can/should get the booster in the US and my doctor said yes, they should. We were able to get them a Pfizer booster shot at the Costco Pharmacy in Woodinville (walk-in, on a weekday). We took the following documents to prove they were eligible for a booster in the US:
Printout from CDC which states: if you got a vaccine out of US, it has to be a recommended dose as outlined from the WHO list (scroll down to the “If you were vaccinated outside of the United States” section
Printout from the WHO website which shows the list of recommended vaccines: Covishield is no. 3 on the list
https://extranet.who.int/pqweb/vaccines/vaccinescovid-19-vaccine-eul-issued
Seeing the 2 documents, the pharmacy agreed to give my parents the booster. Further, they also recommended that they take the Pfizer booster since that works well with Covishield. They had to show proof of their 1st and 2nd shot. After receiving the booster, my parents received the CDC card which had the date of the booster.