Cytomegalovirus reactivation following COVID-19 vaccination: A case report

ABSTRACT

Case report Cytomegalovirus (CMV) causes latent asymptomatic infection in most adults worldwide. Immunodeficiency or immune activation can disrupt viral suppression and lead to viral reactivation, occasionally causing a mononucleosis-like illness in otherwise healthy immunocompetent people. A 37-year- old female presented with a 10-day history of fevers, chills, right-sided neck tenderness, rapidly expanding rash, as well as myalgia, arthralgia, and weakness. She had received her first dose of tozinameran (Pfizer-BioNTech COVID-19 mRNA vaccine) 11 days prior to symptom onset. She was admitted to hospital for further investigations, and was seen by an allergy/clinical immunology specialist, with the diagnosis initially felt to be a delayed serum sickness-like reaction to the vaccine. On admission to hospital, the patient was febrile (37.8C) and tachycardic (122 beats/min). Her physical examination was remarkable for right-sided submandibular tenderness, diffuse blanchable, nonpruritic, erythematous, maculopapular rash, and mild facial swelling. There were no effused joints, lymphadenopathy, nor splenomegaly. Bloodwork showed pancytopenia and mild liver transaminase elevation. Blood cultures were negative. Multiple PCR tests for COVID-19 were negative. Monospot and serology for HBV, HIV, and B. burgdorferi were negative. CMV serology was positive, but unavailable until after discharge. ANA and rheumatoid factor were negative. CT head demonstrated nonspecific edema in the right submandibular area without abscess. On outpatient follow-up, the patient reported symptom resolution over two months. Repeat CMV titres two months post hospitalisation showed strongly elevated IgG, which upon consultation with infectious diseases was felt to represent CMV reactivation (Table 1). CMV viral load was negative. Pancytopenia resolved and transaminases normalized. She received her second dose of tozinameran 4 months post first dose with prophylactic valacyclovir 1g once daily for 1 week prior to and 1 week post vaccination as recommended by infectious diseases and remained asymptomatic. This case is the first known description of CMV reactivation secondary to COVID-19 vaccination. It may be underdiagnosed due to nonspecific symptomatology, as CMV seropositivity ranges from 60-100% of all adults. While causality has yet to be established, recognition of this condition may allow appropriate treatment and prophylaxis in order to facilitate safe COVID-19 vaccination in affected individuals. The patient has provided verbal consent through the telephone for the publication of this case report due to the current COVID-19 pandemic, with written consent to follow.