Background Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes Coronavirus disease 2019 (COVID-19). This study aimed to determine if SARS-CoV-2 RNA in serum at admission correlated with clinical outcome in COVID-19. Methods COVID-19 patients admitted to the Infectious Diseases department of a tertiary level Swedish hospital, and sampled for SARS-CoV-2 RNA in serum at admission, April 10 to June 30 2020 were included in a cohort. Primary outcomes were day 28 all-cause mortality and progress to critical disease. Results The cohort (N=167) consisted of 106 SARS-CoV-2 RNA serum negative and 61 positive patients. Median sampling time for initial SARS-CoV-2 in serum was 1 (IQR 1-2) day after admission corresponding to day 10 (IQR 8-12) after symptom onset. Median ages were 53 (IQR 44-67) and 63 (IQR 52-74) years for the PCR-negative and positive patients, respectively. In the serum PCR negative and positive groups 3/106 and 15/61 patients died, respectively. The hazard ratios for critical disease and all-cause mortality were 7.2 (95% CI 3.0-17) and 8.6 (95% CI 2.4-30), respectively for patients that were serum PCR positive compared to serum PCR negative. Conclusion: SARS-CoV-2 RNA in serum at hospital admission indicates a high-risk of progression to critical disease and death.

We report an enterovirus D68 (EV-D68) outbreak in Stockholm Sweden in 2016. Between 22 August and 25 September EV-D68 was detected in 74/495 respiratory samples analysed at the Karolinska University Hospital. During the peak week, 30/91 (33%) samples were EV-D68 positive. Viral protein (VP)P4/VP2 sequencing revealed that cases were caused by B3 lineage strains. Forty-four (59%) EV-D68-positive patients were children aged ≤ 5 years. Ten patients had severe respiratory or neurological symptoms and one died.

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BACKGROUND Influenza remains a constant threat worldwide, and WHO estimates that it affects 5% to 15% of the global population each season, with an associated 3 to 5 million severe cases and up to 500000 deaths. To limit the morbidity and the economic burden of influenza, improved diagnostic assays are needed. METHODS We developed a multiplexed assay for the detection and subtyping of seasonal influenza based on padlock probes and rolling circle amplification. The assay simultaneously targets all 8 genome segments of the 4 circulating influenza variants—A(H1N1), A(H3N2), B/Yamagata, and B/Victoria—and was combined with a prototype cartridge for inexpensive digital quantification. Characterized virus isolates and patient nasopharyngeal swabs were used for assay design and analytical validation. The diagnostic performance was assessed by blinded testing of 50 clinical samples analyzed in parallel with a commercial influenza assay, Simplexa™ Flu A/B & RSV Direct. RESULTS The assay had a detection limit of 18 viral RNA copies and achieved 100% analytical and clinical specificity for differential detection and subtyping of seasonal circulating influenza variants. The diagnostic sensitivity on the 50 clinical samples was 77.5% for detecting influenza and up to 73% for subtyping seasonal variants. CONCLUSIONS We have presented a proof-of-concept padlock probe assay combined with an inexpensive digital readout for the detection and subtyping of seasonal influenza strains A and B. The demonstrated high specificity and multiplexing capability, together with the digital quantification, established the assay as a promising diagnostic tool for seasonal influenza.