Fever one to two days after injection

Do you filter the solution? Was the batch tested? Is the liquid still clear or has it gone cloudy? Fever can come from bacteria or endotoxins, so I would stop that vial.

Could still be unrelated to the vial; there are more colds and viruses going around than usual for this season.

Might be endotoxins; was the batch checked for those?

So the vial was four to five months old? Is it reta or tirz?

I have seen the same thing happen, though with kids bringing home school germs it was impossible to know the source. A 103.5 fever is high; at 105 seizures become possible. If genuinely worried about health, see a doctor or go to hospital.

I would have headed to the ER with a 103.5 fever.

Endotoxin testing on the batch came back as not detected. Product is reta. Vial has been mixed for four weeks. First two shots from this vial and six from the prior one were fine. Everything I have read says endotoxins act within hours and usually cause site reactions too. Another strange detail is the fever simply disappears instead of breaking the way a normal illness fever does. It is gone now and temperature is back to 98.6.

No filtering and no word on sterility or endotoxin results. Anyone have a crystal ball handy?

Most likely explanation remains a viral infection; fever often appears first and other cold or flu symptoms usually follow within a day or two. Adults average a couple of these each year, so coincidence is probable and the injection may have nothing to do with it. Subcutaneous shots rarely cause widespread infection compared with IV. Watch how you feel overall, use fever reducers if needed, stay hydrated, and seek care if symptoms change or you have other medical conditions.

I would not continue with that vial. Two fevers of 102–103 with chills at roughly the same interval after dosing from the same product is reason enough to stop and speak with a doctor. Lack of local reaction does not rule out a systemic response. It could be unrelated, yet the pattern makes me reluctant to call it a normal side effect. Keep the vial and all timing details in case they are needed later. With temperatures hitting 103.5 I would focus on finding the cause of the repeated high fevers rather than asking if others have seen it.

Wait a couple of weeks; if the fever returns you will know it was not the product. Unlikely anyway since the first shots were fine. Could be one of the other compounds or simply a virus, which seems the most common reason.

After rereading, the second occurrence makes contamination of the vial worth taking more seriously, so I would not reuse it. Still, how sick you feel should guide whether medical review is needed. Any non-virus symptoms would make checking advisable, especially with any relevant medical history. A virus typically produces a temperature that fades rather than returns, though that can happen. Endotoxin from manufacture would have shown from the first shot and required a large amount to cause this fever, so any contamination would more likely be growth inside the vial after mixing; even then it remains uncommon.