Objectives:
What are the epidemiological, clinical, radiological and laboratory features, as well as therapeutic and prognostic aspects, of COVID‐19 in children?

Study design:
This review article included 46 articles, reporting 551 laboratory‐confirmed cases of COVID‐19 in children between early January and late March 2020, of which 429 cases (78%) were from China, 11 cases (2%) from other Asian countries and 110 cases (20%) from Europe (Italy and Spain).

Objectives:
Undernutrition is associated with an elevated risk of mortality among children in low- and middle-income countries. Small-quantity lipid-based nutrient supplements (LNS) have been evaluated as a method to prevent undernutrition and improve infant development, but the effects on mortality are unknown. Therefore, this review article has been conducted.

Objectives:
Hydroxychloroquine has been promoted for its use in treatment of COVID-19 patients based on in-vitro evidences. Therefore, this review article has been conducted.

Does hydroxychloroquine, given as add on to the standard care reduce mortality risk among COVID-19 patients?

Objectives:
Is there a causal relationship between tomato consumption and lowering effects on cholesterol, triglycerides or fasting blood sugar levels?
 
Study design:
This review article included 6 RCTs.

Results and conclusions:
The investigators found tomato consumption significantly reduced total plasma cholesterol levels [WMD = -4.39 mg/dL, 95% CI = -7.09 to -1.68, I2 = 48%, p = 0.05].

Objectives:
Are there differences in the laboratory findings between severe patients and non-severe patients with COVID-19?

Study design:
This review article included 35 articles with a total of 5,912 patients with COVID-19.

Objectives:
Does influenza vaccination reduce mortality risk among adult and elderly patients with type 1 and type 2 diabetes?

Study design:
This review article included 6 observational studies.

Results and conclusions:   
The investigators found influenza vaccination was associated with a 46% lower mortality rate [MH-OR = 0.54, 95% CI = 0.40 to 0.74, p 0.001] among adult and elderly patients with type 1 and type 2 diabetes.

Objectives:
Is the severity of COVID-19 associated with liver damage?

Study design:
This review article included 8 articles comprising 7,467 COVID-19 patients.

Results and conclusions:   

Objectives:
An increased risk of gastric cancer for pickled vegetable and salted fish intake has been suggested, yet the lack of a dose-response association warrants a quantitative analysis. Therefore, this review article (meta-analysis) has been conducted.

Do pickled vegetable and salted fish intakes increase risk of gastric cancer?

Study design:
This review article included 21 cohort studies with a total of 195,624 participants for the analysis of pickled vegetable intake and 16 cohort studies with a total of

Objectives:
Is there an association between COVID-19 severity and mortality rate with the history of cardiovascular diseases and/or other comorbidities and cardiac injury laboratory markers?   

Study design:
This review article included 56 studies with 17,794 COVID-19 patients.

Results and conclusions:   

Objectives:
Is intralesional injection of mumps-measles-rubella (MMR) vaccine associated with a higher complete response in cutaneous warts?

Study design:
This review article included 5 RCTs with a total of 425 subjects.