Notes from 6 month well child visit 1/22/19: Parents describe that they never called to tell us what happened however after his 4 month immunizations he became fussy and had a fever. This occurred a few hours after he was given his 4 month vaccines including rotavirus vaccine. Mom gave him a dose of TYLENOL and almost immediately after taking the TYLENOL he began vomiting profusely and retching and vomiting repeatedly over several minutes and became very limp, poorly responsive, or facial contact, infrequent movements of his extremities, and floppiness. This was the second time he had ever had TYLENOL and he has never had TYLENOL since then. Continuation of notes from follow up well child (6 month) visit dated 1/22/19: The fever and fussiness and lethargy did not recur that the lethargy itself lasted about 30 minutes and they did call 911. Emergency medical technicians did observe the baby and told the family that this happens with infants sometimes after vomiting. I talked with the family about apparent life-threatening events which sometimes occurring very young infants often under one month of age related to vomiting, secondary laryngospasm and transient diminished consciousness and decreased responsiveness after the episode of laryngospasm. This is different than what the family describes. There was no arching or breath holding or difficulty breathing, there was only profuse vomiting followed by lethargy immediately after the TYLENOL. The family history of food allergy is negative. Dad does have seasonal allergies for which she gets a shot of long-acting steroid every spring. There is no family history of eczema. There is no family history of asthma. There are some extended family members on mom's side of the family that have seasonal allergies. Does not yet started any solids. He is on 24-calorie formula. Weight gain is steady but I think he still needs to 24-calorie formula and we talked today about advancement to solids. At this time we are going to withhold his third dose of rotavirus vaccine due to fever profuse vomiting and lethargy however overall the timing of the response seems most tied to the TYLENOL that we cannot be sure. After he gets his vaccines today not including rotavirus, we will schedule to see him back in a couple of weeks for a challenge in office using the TYLENOL. We will have epinephrine at the ready. Occasionally profuse vomiting and lethargy secondary to hypotension. The only sign of allergic reaction. There is of course a type of allergic response referred to his food protein induced enterocolitis syndrome though classically the vomiting occurs approximately 2 hours after ingestion and this response was immediate. There never was a rash or apparent facial swelling in association with this episode. Just for safety we will retry TYLENOL in the office and if they need something for fever before then they can use ibuprofen. Notes from in office TYLENOL challenge 1/31/19: In office today, he is alert and taking a bottle. At 1145 he is given half a teaspoon of infant TYLENOL based on his weight. He does not have any initial emesis or lethargy. He does have a baseline blood pressure in the left arm of 88/52. We will watch him every 5 minutes for 20 minutes however, his previous reaction was immediate and was followed with significant lethargy and decreased responsiveness. This does not happen here today. His ending blood pressure was 80/52 in the left arm and he is comfortable. We suspect the initial reaction was secondary to rotavirus vaccine at 4 months. The reason for suspecting this was that the reaction happened within a couple of hours and was gastrointestinal in nature. Additionally, we then gave him his 6 month vaccines without rotavirus and he did fine. We also tested TYLENOL today because prior to the event he had just had a dose of TYLENOL and so we had the family bring their bottle from home and observed him with close monitoring in the office and he did not have the same kind of reaction. Finally, his father had a similar reaction to the actual disease in that it presented with fever and profuse vomiting followed by collapse which actually resulted in his stopping breathing and he was hospitalized for 9 days. That reaction happened immediately after he first had emesis as a child with rotavirus infection.  Dad has not subsequently had any episodes of shock with viral illnesses therefore we are not especially concerned about metabolic disorders. Expanded newborn screen is negative for patient. Both dad and the patient had a similar episode of profuse vomiting followed by transient collapse in association either with rotavirus vaccine (patient) or rotavirus disease (dad). Lastly, the patient did not have signs of other viral illness either leading in to vaccines or subsequent to the transient event. Clearly patient's reaction was less severe as unlike his father, he did not require rescue breaths or a hospitalization however it was a fairly severe event (see description above). We will file a vaccine adverse event report. A release of information is obtained from mom.