Anderson Cooper: Ricky asked if I receive a vaccine in a foreign country say New Zealand or England will be effective against the virus and its mutations here in the US or will additional vaccinations be necessary?

Dr. Leana Wen: Well, at some point, I do hope that we'll get many different types of vaccines. And it may be that certain countries have more of one type of vaccine than another. There's no reason for us to believe that there's any kind of geographic variation when it comes to one vaccine been effective in one part of the country or other. But I agree with what Sanjay said that it may turn out that one vaccine is more effective in older individuals or children or people with cancer or other conditions and that remains to be seen

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