Pfizer COVID-19 vaccine deemed safe among children with chronic urticaria

Key takeaways:

• 64% of the children with chronic urticaria did not report any symptoms after the first dose of the BNT162b2 COVID-19 vaccine.
• The most common symptoms after both vaccine doses were injection site reactions.

The Pfizer-BioNTech BNT162b2 COVID-19 vaccine was not associated with any risk for adverse reactions among children with chronic urticaria, according to a study published in The Journal of Allergy and Clinical Immunology: In Practice.

Also, COVID-19 infections among these children did not precipitate any chronic urticaria flares either, Catherine K. Zhu, MD, faculty of medicine, McGill University, Montreal, and colleagues wrote.

Atopy is considered a risk factor for hypersensitivities after vaccination such as urticaria, angioedema and anaphylaxis, the researchers said, prompting them to hypothesize that children with chronic urticaria may be at more risk for adverse reactions.

The study recruited 101 children (50% boys; median age, 13 years) from a registry of patients with chronic urticaria attending three allergy clinics in Montreal and the Sheba Medical Center in Israel between December 2021 and March 2022.

According to the researchers, 76 (75%) of the children had isolated chronic spontaneous urticaria (CSU), 14 (14%) had isolated chronic inducible urticaria (CIndU) and 11 (11%) had both concurrently.

After 74 (73%) of the cohort received the first dose of BNT162b2, 47 (64%) of them did not have any symptoms. Also, 20 (27%) had an injection site reaction (ISR) such as erythema, soreness or swelling.

Six (8%) of the patients who had received the first dose of the vaccine had flu-like symptoms including chills, fatigue, arthralgia, headache, mild fever or myalgia. One (1%) had a high fever, classified as higher than 39°C.

Next, 56 (55%) of the children had a second dose of the vaccine, with 26 (46%) not reporting any symptoms, 18 (32%) reporting ISR, 10 (18%) reporting flu-like symptoms, one (2%) reporting high fever and one (2%) reporting nausea.

The researchers further reported that 18 (17%) of the children were waiting to schedule their second dose of the vaccine at the time of the study.

None of the patients reported any allergic reactions, including CSU exacerbations, nor did any of them report chest discomfort or palpitations, after the first or second doses of the vaccine.

Also, the researchers said they did not find any statistically significant difference between the proportions of children who reported each type of side effect after the first and second doses of the vaccine.

When the researchers examined the 27 children (27%) who were not vaccinated, they did not find any associations between parental education (adjusted OR = 1.03; 95% CI, 0.83-1.28), sex (aOR = 0.93; 95% CI, 0.77-1.13) or 7-day Urticaria Activity Score (aOR = 0.99; 95% CI, 0.97-1).

Older children were more likely to be vaccinated (aOR = 1.05; 95% CI, 1.02-1.08). Also, the children in the unvaccinated group were more likely to be taking higher doses of second-generation antihistamines than those who were vaccinated (P < .01).

These higher doses of second-generation antihistamines among children who have not been vaccinated suggest that children with chronic urticaria who are more treatment-resistant are more likely to be vaccine-hesitant due to fears of urticaria flareups, the researchers said.

Among the 17 patients (17%) who developed COVID-19, nine (53%) were unvaccinated at the time of infection. Ten (59%) of them experienced flu-like symptoms, and five (29%) were asymptomatic.

One of the patients (aged 14 years) with CSU experienced an eczema flareup that lasted for 12 hours and improved after topical hydrocortisone was applied.

With most adverse effects characterized as minor, the researchers concluded that children with chronic urticaria have minimal risk for developing an allergic reaction due to COVID-19 vaccination and that COVID-19 infections do not precipitate chronic urticaria flares.

But although these findings indicate that the BNT162b2 vaccine is safe for children with chronic urticaria, the researchers continued, they recommended assessments of the safety of mRNA COVID-19 vaccines among children aged 6 months to 5 years since vaccines are now approved for that age group as well.