How long for side effects to start after nasal flu vaccine?

[GnomeyGnome]

DS (14) had his nasal flu vaccine at school yesterday at around 10am. Felt absolutely fine yesterday and today until around 2pm when he got a headache, sore throat and shivers. His temp is currently 37.9 but school gave him a paracetamol so not sure if his temp is artificially lowered if that makes sense. Just wondering if this could just be side effects from the vaccine or he's coming down with something else. Won't necessarily change what we do right now but the thought of getting a PCR has popped in to my head as headache and sore throat seemed to be the main symptoms in DS's classmates who had Covid.
I know they change the vaccine each year but just in case it's relevant, he has it each year and has never had side effects.

My granddaughter started feeling like crap only 4 hours after having the nasal vaccination.

Yes I would've expected a quicker reaction, I had mine at lunchtime and by tea time had an awful headache and sore arm so DS feeling so poorly 28 hours later surprised me... He's in bed asleep now, unheard of!

Can I ask what side effects your granddaughter had?

Ds and I were feeling rough within hours, both headache and shivery.

She had a slightly raised temperature (38 C),a headache and ached all over. Also felt a bit sick. It lasted for about 18 hours.

Last year 120 of our pupils received the nasal flu vaccine and only one reported a possible reaction. In our experience a reaction (other than sneezing and watery eyes IMMEDIATELY after the vaccine) is very unusual so in OPs position I would be getting DC a PCR test.

Very common
(may affect more than 1 in 10 people):
 runny or stuffy nose
 reduced appetite
 weakness
 headache
Common
(may affect up to 1 in 10 people):
 fever
 muscle aches
oxleas.nhs.uk/site-media/cms-downloads/Nasal_Flu_-_Fluenz_Tetra_Patient_Information_Leaflet.pdf

Last year my son got side effects a couple of days after (confirmed by a doctor as I was worried about him)

DS had his vaccine on monday, was fine, if a little sniffy, til tuesday. He felt a bit rough on tuesday but OK for school, today he's been floored by it!
No temp, just massive migrainey headache and achey joints.
I had the jab and also had migrainey headaches and achey joints for 2 days this year, never usually have anything!

Neither of our dc were ill after having it.

We were advised to get a PCR if they had a raised temperature after having it, not for aches and sore throat.

Your dc’s temp is likely to be slightly lower after having paracetamol so in your shoes I’d be getting them a PCR.

Hope they pick up soon.