Scroll down in the following link and you will note that 'Cold' like symptoms,coughs, headaches, muscle aches, etc: can follow on from the Flu Jab. https://www.webmd.boots.com/cold-and-flu/flu-guide/flu-jab-side-effects Hans.
Don't think so Cat. "She who must be obeyed" and myself have been laid up with a bad cold for about 9 days. Came on about 4 days after the jab. We have heard of many more having the same cold afterwards. It is still better than getting influenza with no natural antibodies to resist the latest strain. Take care get plenty of rest and keep warm. If you get the cough as well my sympathy goes out to you.
I once worked for a governor who thought it would be a good idea for all his staff have the flu jab. (It was nothing to do with his concern for their welfare - it was simply to cut down his sick absence - and hence his costs - in the winter). So he arranged a private company to come in and we all dutifully lined up to be injected. Before I got home that evening I felt absolutely dreadful and took to my bed. I remained there for about six days feeling as if I wanted to die. It took me a good week after that to recover and I had a week off afterwards for good measure. I've only had flu twice apart from that and neither episode was anything like as bad as the one following my protection from the disease.
While stationed in Belfast in the late 70s, it was thought prudent for the regiment to have their flu jabs on a staggered basis, with each 'batch' 3 or 4 days apart.
I'm not sure that a heavy cold and a mild cold type reaction are the same thing but anyhoo, yes it's a coincidence, cold and flu are different viruses.
Yes there's too much evidence to flatly dismiss it as a coincidence. At the least it might reduce immunity to other viruses such as the cold for a while.