Abstract Background: Cytomegalovirus (CMV) is a crucial pathogen in immunocompromised individuals, causing infections such as pneumonitis, colitis, and retinitis. However, research on CMV infections of the central nervous system (CNS) is limited. Objective: This retrospective cohort study enrolled patients with a CMV meningitis or encephalitis diagnosis and analyzed their underlying conditions, clinical manifestations, laboratory findings, treatments, and outcomes. Methods: The study included patients who had positive results in quantitative polymerase chain reaction (PCR) tests of their cerebrospinal fluid (CSF) for CMV at any time between January 2017 and December 2022. Clinical characteristics, laboratory findings, treatment approaches, and outcomes were reviewed and analyzed from electronic medical records. Results: The cohort comprised 12 patients with a median age of 61 years (range, 43–84 years). Stupor and generalized seizures were the most common neurological presentations. Brain imaging in half of the patients revealed nonspecific abnormalities, such as atrophy. CSF protein levels were elevated, with a median of 74.5 mg/dL. CSF pleocytosis was observed in three patients (25%) and was predominantly lymphocytic. The in-hospital mortality rate was 75% (9 out of 12 patients). Conclusions: Although rare, CMV CNS infections are associated with a high mortality rate. CSF pleocytosis is uncommon in such cases, potentially contributing to clinical misdiagnosis or underestimation. CMV meningoencephalitis should be considered in immunocompromised patients who present with unexplained seizures or altered consciousness.

Background Physical distancing and facemask use are worldwide recognized as effective non-pharmaceutical interventions (NPIs) against the coronavirus disease 2019 (COVID-19). Since January 2020, Taiwan has introduced both NPIs but their effectiveness on non-COVID-19 respiratory viruses (NCRVs) remain underexplored. Methods This retrospective observational study examined electronic records at a tertiary hospital in northern Taiwan from pre-COVID (January–December 2019) to post-COVID period (January–May 2020). Patients with respiratory syndromes were tested for both enveloped (e.g. influenza virus and seasonal coronavirus) and non-enveloped RVs (e.g. enterovirus and rhinovirus) using multiplex reverse-transcription polymerase chain reaction assays. Monthly positivity rates of NCRVs among adult and pediatric patients were analyzed with comparison between pre- and post-COVID periods. Results A total of 9693 patients underwent 12127 multiplex RT-PCR tests. The average positivity rate of NCRVs reduced by 11.2% (25.6% to 14.4%) after nationwide PHIs. Despite the COVID-19 pandemic, the most commonly identified enveloped and non-enveloped viruses were influenza virus and enterovirus/rhinovirus, respectively. Observed reduction in NCRV incidence was predominantly contributed by enveloped NCRVs including influenza viruses. We did not observe epidemiological impacts of NPIs on non-enveloped viruses but an increasing trend in enterovirus/rhinovirus test positivity rate among pediatric patients. Our data were validated using Taiwan’s national notification database. Conclusions Our frontline investigation suggests that the current NPIs in Taiwan might not effectively control the transmission of non-enveloped respiratory viruses, despite their protective effects against influenza and seasonal coronavirus. Hydrogen peroxide or chloride-based disinfectants should be integrated into national preventative strategies against respiratory viral infections in the post-COVID-19 era.