Prevalence of SARS-CoV-2 infection in general practitioners and nurses in primary care and nursing homes in the Healthcare Area of León and associated factors.

OBJECTIVE: To evaluate the prevalence of and factors associated with SARS-CoV-2 infection in general practitioners and nurses from primary care centers and nursing homes in the Healthcare Area of León (Spain). MATERIALS AND METHODS: Cross-sectional study in a convenience sample of professionals from 30 health centers and 30 nursing homes from the primary care management division of the Healthcare Area of Leon. The work center, type of profession, COVID-19 infection, level of exposure, compliance with preventive measures, isolation (if required) and diagnostic tests carried out were collected. The determination of infection was made by differentiated rapid diagnostic test (dRDT), using a finger-stick whole-blood sample. The association of variables with infection was assessed by multivariable non-conditional logistic regression. The true prevalence of SARS-CoV-2 infection was calculated according to two scenarios for RDT (Sensitivity=0.6 and Specificity=0.985; Sensitivity=0.8 and Specificity=1). RESULTS: The true prevalence of SARS-CoV-2 infection was between 4.9% and 11.0%. The observed prevalence was 5.9% and was higher in nursing homes than in primary care centers (9.5% vs. 5.5%). No statistically significant differences were observed by sex, type of professional, level of exposure or compliance with preventive measures. CONCLUSIONS: The prevalence of SARS-CoV-2 infection in this group is low. A high number of professionals remain susceptible to SARS-CoV-2 infection and therefore protective measures should be taken, especially for professionals working in nursing homes.

Predictive factors of COVID-19 in patients with negative RT-qPCR.

OBJECTIVE: To evaluate the factors associated with false negatives in RT-qPCR in patients with mild-moderate symptoms of COVID-19. MATERIALS AND METHODS: This was a cross-sectional study that used a random sample of non-hospitalized patients from the primary care management division of the Healthcare Area of Leon (58 RT-qPCR-positive cases and 52 RT-qPCR-negative cases). Information regarding symptoms was collected and all patients were simultaneously tested using two rapid diagnostic tests - RDTs (Combined - cRDT and Differentiated - dRDT). The association between symptoms and SARS-CoV-2 infection was evaluated by non-conditional logistic regression, with estimation of Odds Ratio. RESULTS: A total of 110 subjects were studied, 52% of whom were women (mean age: 48.2±11.0 years). There were 42.3% of negative RT-qPCRs that were positive in some RDTs. Fever over 38°C (present in 35.5% of cases) and anosmia (present in 41.8%) were the symptoms most associated with SARS-CoV-2 infection, a relationship that remained statistically significant in patients with negative RT-qPCR and some positive RDT (aOR=6.64; 95%CI=1.33-33.13 and aOR=19.38; 95% CI=3.69-101.89, respectively). CONCLUSIONS: RT-qPCR is the technique of choice in the diagnosis of SARS-CoV-2 infection, but it is not exempt from false negatives. Our results show that patients who present mild or moderate symptoms with negative RT-qPCR, but with fever and/or anosmia, should be considered as suspicious cases and should be evaluated with other diagnostic methods.