Childhood deaths from pneumonia is almost 2000 times higher in developing countries than in developed countries. In 1970, pneumonia was responsible for 9% of all deaths in children under 5 years. This rate was 2% in 2007.

Some studies have shown that supplementing with vitamin D reduces disease of the respiratory tract infection. Some other studies have shown anti-inflammatory effect of vitamin D in cell lines. Studies about the role of vitamin D supplementation in pneumonia in children are inadequate to conclude about its role.

The aim of this study is to determine the efficacy of vitamin D supplementation in Respiratory Index of Severity in Children (RISC) hospitalized clinical outcomes of hospitalized patients with community-acquired pneumonia.

Inclusion criteria

• Aged between 2 months to 6 years
• Definite diagnosis of pneumonia

Exclusion criteria

• Immunocompromised patients
• Airway hypersensitivity or asthma
• allergies
• nasal polyps
• Using inhaled medications to one month prior to the study
• Receiving high doses of vitamin D
• Avoiding to complete informed consent form