RESULTS
In total, 390 persons (89% females, mean age of 49±16 years) were vaccinated in the hospital. 303 (78%) persons were referred because they had reacted adversely within four hours after a previous COVID-19 vaccination, of which 67 (22%) were treated with epinephrine. Fourteen patients were referred because of an allergy to one the excipients of the COVID-19 vaccine. Of the 390 persons, 154 (39.5%) had comorbidity of allergic rhinitis and/or asthma, 24 (6.2%) had chronic urticaria, and 5 (1.3%) had an underlying mast cell disorder.
Of the 303 persons that reacted to a Covid-19 vaccine, 112 (28.7%)had a moderate to severe reaction. These moderate to severe reactions presented with the following symptoms: generalized urticaria/erythema (n=51; 13.1%), angioedema (n= 56; 14.4%), hypotension (n=17; 4.4%), or stridor/decrease of oxygen saturation (n=15; 3.8%). 166 persons (42.5% ) reacted mildly experiencing: a tight throat, shortness of breath, localized skin rash, itch, tingling sensation or numbness of skin, abdominal pain, vomiting and/or diarrhea, rhinorrhea/conjunctivitis, malaise, decreased alertness, headache, dizziness or palpitations.
Of the 390 persons that were vaccinated, 387 received a full dose of the vaccination. Most persons received a Comirnaty vaccination (358/387=93%), 29 persons received different vaccines because of various reasons.
Of the 387 persons fully vaccinated in hospital, 77 persons reacted adversely. Six of the 387 persons (1.6%) that received a full dose in the hospital had a moderate to severe immediate reaction that were treated with epinephrine, and two of them were observed for an extended amount of time (table). Notably 4 of these 6 persons had severe reactions in the past to a previous administration of a Comirnaty vaccine, 1 had anaphylaxis to several drugs and a different (unknown) vaccine and 1 person had anaphylaxis to food. In 5/6 patient’s tryptase was assessed during the reaction but in none it was elevated. In none of the 6 patients an allergic reaction was diagnosed. In retrospection, the two patients responding to food and drugs/ vaccines respectively epinephrine was given out of precaution.
71 persons had a ‘mild’ reaction that was less severe, or as severe as the previous reaction. 67 persons were treated with epinephrine out of the hospital due to an adverse reaction following a previous COVID-19 vaccination All of them were revaccinated: 44 (64.7%) with the same vaccine, 6 (9.0 %) with another vaccine, the remaining with another vaccine because of other/logistic reasons. In 25/67 (37.3%) persons, symptoms were reported for which 11/25(28%) persons received treatment. None of these 67 persons had a moderate – to severe immediate reaction.
The value of skin tests was limited, as neither a positive nor a negative the skin test result could predict whether a patient would respond to the vaccine with an adverse reaction, also shown in other studies (Wolfson et al, Greenhawt et al).