My dad had the jab and had a dead arm. My mum, who continued working the day after a major operation because she's a nutter, had the jab and was absolutely wrecked by it. Only the third time in my life I've known her bed ridden, aches all over, hot and cold, migraine, the lot. So I wouldn't want to presume they're lying, as much as they probably are just using it as another excuse to be lazy. I've heard some people had an awful time, and others just sail through (this is all the Oxford one. I've heard phizer seems a bit kinder.)