Effectiveness of wearing masks during the COVID-19 outbreak in cohort and case-control studies: a systematic review and meta-analysis

OBJECTIVE

To evaluate the efficacy of wearing a mask to prevent COVID-19 infection.

METHODS

This was a systematic review and meta-analysis of cohort and case-control studies, considering the best level of evidence available. Electronic databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Clinical Trials.gov) were searched to identify studies that evaluated the effectiveness of wearing masks compared with that of not wearing them during the COVID-19 pandemic. Risk of bias and quality of evidence were assessed using the Cochrane risk of bias tool and the Grading of Recommendations Assessment, Development, and Evaluation.

RESULTS

Of the 1,028 studies identified, 9 met the inclusion criteria (2 cohort studies and 7 case-control studies) and were included in the analysis. The meta-analysis using cohort studies alone showed statistically significant differences, wearing a cloth mask decreased by 21% [RD = -0.21 (95% CI, -0.34 to -0.07); I2 = 0%; p = 0,002] the risk of COVID-19 infection, but the quality of evidence was low. Regarding case-control studies, wearing a surgical mask reduced the chance of COVID-19 infection [OR = 0.51 (95% CI, 0.37-0.70); I2 = 47%; p = 0.0001], as did wearing an N95 respirator mask [OR = 0.31 (95% CI, 0.20-0.49); I2 = 0%; p = 0.00001], both with low quality of evidence.

CONCLUSIONS

In this systematic review with meta-analysis, we showed the effectiveness of wearing masks in the prevention of SARS-CoV-2 infection regardless of the type of mask (disposable surgical mask, common masks, including cloth masks, or N95 respirators), although the studies evaluated presented with low quality of evidence and important biases.

Mucosal leishmaniasis . Current scenario and prospects for treatment

Leishmaniasis causes significant morbidity and mortality and thus constitutes a serious public health problem. Even though it has long been endemic in developing countries, in recent years the economic globalization and the increased volume of international travel have extended its prevalence in developed countries. In addition, native populations may be exposed to the infection through blood transfusion and the use of blood products produced from infected asymptomatic individuals. Mucosal leishmaniasis (ML) is a chronic form of this infection, which attacks the mucosa. In most cases this form of leishmaniasis results from the metastatic spread of Leishmania (Viannia) braziliensis from cutaneous lesions. It is a healthcare issue because of its wide demographic distribution, its association with significant morbidity levels, and because of the pressing concern that tourists who travel to endemic areas might present the disease even years later. The treatment currently available for ML is based on drugs such as pentavalent antimony-containing compounds, amphotericin B deoxycholate and pentamidine and often guarantees a satisfactory clinical response. Nevertheless, it also frequently provokes serious side effects. This review offers a critical analysis of the drugs now available for the treatment of ML as also of the future prospects for the treatment of the disease.

Prevalence of mycobacteremia in patients with AIDS and persistant fever

In the advanced stages of AIDS, characterized by severe immunodepression, tuberculosis (TB) may present with a clinical picture of septic shock, due to typical bacteremia. Hematogenic dissemination of mycobacteria is frequent in immunodepressed patients with TB or disseminated mycobacteriosis, leading to increased positivity in detection by automated blood culture. The objective of our study was to determine the prevalence of mycobacteremia in patients with AIDS and with prolonged fever seen at the Emilio Ribas Institute of Infectology. Patients with a history of daily fever (> or = 37.8 degrees C), lasting more than 30 days, and with CD4+ helper lymphocyte counts below 200 cells/mL, were selected from February 2001 to March 2002. A 5 mL peripheral blood sample was collected from each patient for mycobacterial blood culture by an automated method, using the BACTEC 9000 MB and MB/BACT techniques. Forty-five patients aged on average 35 years, most of them males, were included in the study. The mean T CD4+ lymphocyte count was 58 cells/mL. Among the samples submitted to blood culture, 30% gave M. tuberculosis growth, with 62% sensitivity. Among the patients with a negative blood culture, nine had received a diagnosis of TB by another method. Automated blood culture proved to be a technique of relevant diagnostic value for M. tuberculosis in patients with prolonged fever in advanced stages of AIDS. The method is simple, and it helps the physician to select the best therapeutic option.

[Concurrent leishmaniasis and human immunodeficiency virus (HIV) infection: a study of four cases]

Few cases of concurrent leishmaniasis and HIV infection have been reported in Brazil, despite both infections being in expansion. Two cases of visceral leishmaniasis and two cases of mucocutaneous leishmaniasis are discussed. Disseminated skin and oral lesions were found in the patients with the cutaneous form of the disease. Prolonged fever, hepatosplenomegaly and pancytopenia were the main manifestations of the visceral form. The CD4 T lymphocyte count was low in all cases. Direct examination of bone marrow aspirate for leishmania and biopsy of cutaneous lesions are the techniques of choice to confirm diagnosis. Pentavalent antimonials and amphotericin B are preferred drugs for the treatment of leishmaniasis, including patients with AIDS. The authors recommend the inclusion of this parasitosis in the differential diagnosis of opportunistic diseases in patients with AIDS.

Paracoccidioidomycosis in a boy infected with HIV

Paracoccidioidomycosis has been rarely reported among HIV patients, despite being an endemic mycosis in Latin America. The present report illustrates a case of PM in a teenager infected with HIV. Clinicians must be aware that this mycosis may occur in young HIV infected patients who live in endemic areas.