Divergences on expected pneumonia cases during the COVID-19 epidemic in Catalonia: A time-series analysis of primary care electronic health records covering about 6 million people. (preprint)

BackgroundPneumonia is one of the complications of COVID-19. Primary care electronic health records (EHR) have shown the utility as a surveillance system. AimTo analyze the trends of pneumonia during two waves of COVID-19 pandemic in order to use it as a clinical surveillance system and an early indicator of severity. MethodsTime series analysis of pneumonia cases, January 2014-December 2020. We collected pneumonia diagnoses from primary care EHR, covering >6 million people in Catalonia (Spain). We compared the trend of pneumonia in the season 2019-2020 with that in the previous years. We estimated the expected pneumonia cases with data from 2014 to 2018 using a time series regression adjusted by seasonality and influenza epidemics. ResultsBetween 4 March and 5 May 2020, 11,704 excess pneumonia cases (95% CI: 9,909 to 13,498) were identified. We observed a second excess pneumonia period from 22 october to 15 november of 1,377 excess cases (95% CI: 665 to 2,089). In contrast, we observed two great periods with reductions of pneumonia cases in children, accounting for 131 days and 3,534 less pneumonia cases (95% CI: 1,005 to 6,064) from March to July; and 54 days and 1,960 less pneumonia cases (95% CI 917 to 3,002) from October to December. ConclusionsDiagnoses of pneumonia from the EHR could be used as an early and low cost surveillance system to monitor the spread of COVID-19.

A Cluster-Randomized Trial of Hydroxychloroquine as Prevention of Covid-19 Transmission and Disease (preprint)

BackgroundCurrent strategies for preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections are limited to non-pharmacological interventions. Hydroxychloroquine (HCQ) has been proposed as a postexposure therapy to prevent Coronavirus disease 2019 (Covid-19) but definitive evidence is lacking. MethodsWe conducted an open-label, cluster-randomized trial including asymptomatic contacts exposed to a PCR-positive Covid-19 case in Catalonia, Spain. Clusters were randomized to receive no specific therapy (control arm) or HCQ 800mg once, followed by 400mg daily for 6 days (intervention arm). The primary outcome was PCR-confirmed symptomatic Covid-19 within 14 days. The secondary outcome was SARS-CoV-2 infection, either symptomatically compatible or a PCR-positive result regardless of symptoms. Adverse events (AEs) were assessed up to 28 days. ResultsThe analysis included 2,314 healthy contacts of 672 Covid-19 index cases identified between Mar 17 and Apr 28, 2020. A total of 1,198 were randomly allocated to usual care and 1,116 to HCQ therapy. There was no significant difference in the primary outcome of PCR-confirmed, symptomatic Covid-19 disease (6.2% usual care vs. 5.7% HCQ; risk ratio 0.89 [95% confidence interval 0.54-1.46]), nor evidence of beneficial effects on prevention of SARS-CoV-2 transmission (17.8% usual care vs. 18.7% HCQ). The incidence of AEs was higher in the intervention arm than in the control arm (5.9% usual care vs 51.6% HCQ), but no treatment-related serious AEs were reported. ConclusionsPostexposure therapy with HCQ did not prevent SARS-CoV-2 disease and infection in healthy individuals exposed to a PCR-positive case. Our findings do not support HCQ as postexposure prophylaxis for Covid-19. ClinicalTrials.gov registration numberNCT04304053