I do not routinely premedicate prior to TVEC.
However, if a patient has experienced significant flu-like symptoms following a treatment, then would advise them to take acetominophen/ibuprofen for the first 24-48 hours to prevent similar symptoms with subsequent treatments. These symptoms do seem to lessen over time.
There is one exception to that. Patients who have developed adrenal insufficiency, from a prior immunotherapy treatment, do seem more prone to these flu-like symptoms. Additionally, their adrenal glands cannot compensate for the sick-day/physiologic stress of these symptoms. Therefore, in those patients, I do have them premedicate and take anti-pyretics for the first 24 hours following TVEC administration. Additionally, they sometimes do have to follow their sick-day rules for the day of the TVEC treatment and possibly the next day.