1/Brief #COVID19vaccine allergy update: LARGE LOCAL REACTIONS! These all were after #Moderna. Itchy, swollen, erythema, edema. Comes on late (>5 days) and can last weeks .Tx is symptomatic: antihistamine (e.g., fexofenadine), NSAID/Tylenol, ice.
2/ Importantly, you CAN still get the second dose! In the #modernavaccine trial, delayed large locals like these occurred 4x less with 2nd dose than 1st dose. Fewer large locals AND more efficacy, sign me up!
*Potential #anaphylaxis 175 of 1,893,360 1st doses of @pfizer vaccines (0.009%; 90 per million)
*Confirmed #anaphylaxis, 21 of 1,893,360 1st doses of @pfizer vaccines (0.0011%; 11 per million)
-->Better than we thought (1 per 100,000)but greater than usual 1 per million)/2
*17 of 21 Anaphylaxis cases (81%) had allergy history; 7 of 21 (33%) had prior anaphylaxis
*Anaphylaxis occurred a median of 13 min (2–150 min) after vaccination; 71% occurred within 15 min (i.e., CDC recommended waiting/observation time)
*Follow-up for 20 patients & 100% OK /3
2/#allergy and #anaphylaxis can happen to any #drug or #vaccine, but reactions to #COVID19vaccine are exceedingly rare (~6 in >300K vaccinations so far--> 0.002%). #vaccines have always been a rare cause of allergic reactions in healthcare.
2/ There is no reason to think that anyone -- other than patients with a known allergy to an ingredient in this vaccine or an ingredient cross-reactive to an ingredient in this vaccine -- might have an #allergy the @pfizer#CovidVaccine.
3/ There is even very little that we think could cause an #allergy in this @pfizer vaccine. But 2 patients had #anaphylaxis after vaccination and we need to think about why. Something epidemiologically different in the UK population compared to clinical trial populations?
1/OK so there *may* be new reports of allergy to #COVID19 vaccines but many other things (e.g., vasovagal syncope) can be misdiagnosed as allergy so we need more clinical details from the UK cnn.com/2020/12/09/hea…
2/ BUT, it is not surprising that allergic reactions might be identified during massive vaccination but not clinical trials because #allergy to vaccines are exceedingly rare (1 per million). In the @US_FDA report, AEs within 30 min for vaccine vs placebo were similar:
3/Most vaccine allergies come from the excipients and allergists can do skin testing to the vaccine and its excipients (often facilitating safe and totally unremarkable vaccination). Excipients are often shared for many approved vaccines: cdc.gov/vaccines/pubs/…
I am excited for America and #publichealth that my mentor, @RWalensky will be leading the @CDCgov — she is a professor @harvardmed, an #NIH funded scientist, no stranger to testifying in congress, leader of @mgh_id,