RESUMO
The concurrent timing of the COVID-19 pandemic and the seasonal occurrence of influenza, makes it especially important to analyze the possible effect of the influenza vaccine on the risk of contracting COVID-19, or in reducing the complications caused by both diseases, especially in vulnerable populations. There is very little scientific information on the possible protective role of the influenza vaccine against the risk of contracting COVID-19, particularly in groups at high-risk of influenza complications. Reducing the risk of contracting COVID-19 in high-risk patients (those with a higher risk of infection, complications, and death) is essential to improve public well-being and to reduce hospital pressure and the collapse of primary health centers. Apart from overlapping in time, COVID-19 and flu share common aspects of transmission, so that measures to protect against flu might be effective in reducing the risk of contracting COVID-19. In this study, we conclude that the risk of contracting COVID-19 is reduced if patients are vaccinated against flu, but the reduction is small (0.22%) and therefore not clinically important. When this reduction is analysed based on the risk factor suffered by the patient, statistically significant differences have been obtained for patients with cardiovascular problems, diabetics, chronic lung and chronic kidney disease; in all four cases the reduction in the risk of contagion does not reach 1%. It is worth highlighting the behaviour that is completely different from the rest of the data for institutionalized patients. The data for these patients does not suggest a reduction in the risk of contagion for patients vaccinated against the flu, but rather the opposite, a significant increase of 6%. Socioeconomic conditions, as measured by the MEDEA deprivation index, explain increases in the risk of contracting COVID-19, and awareness campaigns should be increased to boost vaccination programs.
RESUMO
Objetive To describe the incidence and mortality of the first wave of COVID-19 in the elderly population of Barcelona, according to their previous levels of frailty. DESIGN: Retrospective cohort study. SETTING AND PARTICIPANTS: Population aged 65 or over assigned to the Barcelona Primary Care centres of the Institut Català de la Salut, followed between March and June 2020. MAIN MEASUREMENTS: Frailty was calculated at baseline from the computerised medical records. Results during follow-up: diagnosis of COVID-19, possible or confirmed with PCR and all-cause mortality. RESULTS: 251788 patients over 64 years of age were analysed, 61.3% had some level of frailty, 27.8% moderate or severe. The incidence of COVID-19 was 3.13 cases per 100 inhabitants (N=7883) and the mortality from COVID-19 was 21.5% (N=1691). Both the incidence and mortality from COVID-19 were higher at older age, in men, at greater deprivation and at a higher level of frailty. Individuals with mild, moderate, and severe frailty had an adjusted Hazard Ratio (HR) for COVID-19 disease of 1.47, 2.08, and 3.50, respectively. Among subjects with COVID-19, those with mild, moderate, and severe frailty had an adjusted HR for COVID-19 mortality of 1.44, 1.69, and 2.47, respectively. CONCLUSIONS: We consider it necessary to address frailty also in a pandemic situation, since it is a treatable condition and in turn a more serious risk factor for COVID-19, where the role of primary care is essential, due to its accessibility and longitudinal character.