After yesterday’s four-in-one vaccine, my dog became listless, vomited, trembled, and seems to have a slight cough

A dog shaking, being listless, and coughing after vaccination can have several causes. First, it may be an allergic reaction to the vaccine, which besides shaking and coughing can cause facial swelling and breathing difficulty. Second, after vaccination dogs may show mild to moderate side effects such as shaking, low spirits, reduced appetite, slight fever, or injection-site discomfort. These usually appear within 24-48 hours and ease on their own in a few days.

Finally, the cough may come from a respiratory disease such as a cold, kennel cough, or canine parainfluenza. Give the dog a quiet, comfortable resting place with enough water and proper food. If symptoms keep worsening, take it to a vet promptly.