COVID vaccine-induced bullous drug eruption and a vaccine conundrum: case report

SARS-CoV-2 vaccines have been associated with various dermatological adverse events including bullous eruptions (Tomayko M, Damsky W, Fathy R et al. Subepidermal blistering eruptions, including bullous pemphigoid, following COVID-19 vaccination. J Allergy Clin Immunol 2021;148: 750- 751;Gambichler T, Boms S, Susok L et al. Cutaneous findings following COVID-19 vaccination: review of world literature and own experience. J Eur Acad Dermatol Venereol 2021;36: 172- 80). Certainly, the association could be coincidental, or it is also possible that a subclinical bullous pemphigoid (BP) was unmasked by vaccination. We present a unique case of BP-like eruption after COVID-19 mRNA vaccine that also posed a dilemma of further suitable vaccination in a patient with platelet disorder. A 57-year-old woman had her first dose of the Pfizer COVID-19 vaccine on 2 February 2021 on her left arm and within 24 h of receiving it she developed bruising of the entire arm. The patient was hospitalized for further investigations when she developed a bullous rash on her left arm that eventually involved her face and legs. Treatment with systemic steroids was commenced. Owing to her complex medical history including platelet disorder and Ehlers-Danlos syndrome, we were posed with a dilemma of a further suitable vaccination. After a multidisciplinary team meeting, the patient has been encouraged to receive a Moderna vaccine for the second dose. Clinicians should be aware of BP-like disease that may develop after COVID-19 mRNA vaccination. However, with the underlying cause of BP being uncertain, the rarity of its occurrences and the greater risks of SARS-CoV-2 infection, it is important to encourage full vaccination including completion in those with blisters after the first dose. Further studies are required to study the natural history of BP-like disease associated with the COVID-19 vaccines.

Meta-analysis of diagnostic performance of serological tests for SARS-CoV-2 antibodies up to 25 April 2020 and public health implications

We reviewed the diagnostic accuracy of SARS-CoV-2 serological tests. Random-effects models yielded a summary sensitivity of 82% for IgM, and 85% for IgG and total antibodies. For specificity, the pooled estimate were 98% for IgM and 99% for IgG and total antibodies. In populations with 5% of seroconverted individuals, unless the assays have perfect (i.e. 100%) specificity, the positive predictive value would be 88%. Serological tests should be used for prevalence surveys only in hard-hit areas.