You're speaking with Dr. Michael Salkin. Welcome to JustAnswer. I'm currently typing up my reply. Please be patient. This may take a few minutes.
Anne, unless Benja suffered a hypersensitivity reaction to that vaccine, there's no mechanism for it worsen congestive heart failure. My concern is more that vaccinating a 16 year against anything may not be advisable. It's questionable if a 16 year old's immune system could muster up an appropriate response to that or any vaccine. If it isn't absolutely necessary to do so, I wouldn't vaccine a dog of Benja's age against anything.
Please respond with further questions or concerns if you wish.
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Thank you for the additional information. I appreciate your taking the time to let me know.