Women and people aged 30 to 69 years may be at higher risk of developing a delayed large local reaction (DLLR) after receiving the mRNA-1273 Covid-19 vaccine from Moderna.
This finding comes from a Japanese study published online in JAMA Dermatology.
The investigators examined the associations between sex, age and susceptibility to DLLRs in a sample of 5,893 individuals who received the vaccine between May 24 and Nov. 30, 2021.
DLLR was considered if a participant reported redness, tenderness, itchiness, thickening or hardening of the skin, a burning sensation or swelling around the injection site on or after the sixth day after injection of the first dose of the vaccine.
Among the participants, 12.7% experienced DLLR symptoms after their first dose of the mRNA-1273 vaccine. Their DLLR symptoms were all mild.
Incidence rates of DLLR were higher in women (22.4%) compared to men (5.1%).
Broken down by age, the incidence rates among those aged 18 to 29 years was 9.0%, ages 30 to 39 years was 14.3%, 40 to 49 years was 15.8%, ages 50 to 59 years was 14.9% and 60 to 69 years was 12.6%.
"The association between demographic characteristics and susceptibility of DLLR suggests that the condition is a type IV allergic skin reaction," the authors write.