HYPOTHESIS: The administration of vitamin D supplements to patients who have a positive diagnosis for SARS-Cov-2, acute pneumonia requiring hospital admission and vitamin D deficiency have a more favourable evolution than subjects not treated with vitamin D (placebo). This favourable evolution will translate into a reduction in mortality, fewer ICU admissions and fewer days of stay in hospital.

OBJECTIVES:

PRINCIPAL: To assess whether the group of patients receiving vitamin D supplements have a less severe evolution of their acute pneumonia, translated into lower mortality, than patients who do not receive that supplement.

SECONDARY: 1) To determine the number of intensive care admissions and the number of days of admission in both groups (control group and intervention group). 2) To estimate the prevalence of Vitamin D deficiency in the patients studied and the effectiveness of its supplementation. 3) To establish the degree of complexity of each study group and carry out a cost-effectiveness study.

METHODOLOGY: DESIGN: Clinical trial, randomized, placebo-controlled and double-blind, with two parallel groups The active treatment will be vitamin D (Hydroferol soft capsules of 0.266 mg). The placebo will consist of a tablet with the same external characteristics and with the same treatment scheme but which will not contain any vitamin D active ingredients.

HYPOTHESIS: The administration of vitamin D supplements to patients who have a positive diagnosis for SARS-Cov-2, acute pneumonia requiring hospital admission and vitamin D deficiency have a more favourable evolution than subjects not treated with vitamin D (placebo). This favourable evolution will translate into a reduction in mortality, fewer ICU admissions and fewer days of stay in hospital.

OBJECTIVES:

PRINCIPAL: To assess whether the group of patients receiving vitamin D supplements have a less severe evolution of their acute pneumonia, translated into lower mortality, than patients who do not receive that supplement.

SECONDARY: 1) To determine the number of intensive care admissions and the number of days of admission in both groups (control group and intervention group). 2) To estimate the prevalence of Vitamin D deficiency in the patients studied and the effectiveness of its supplementation. 3) To establish the degree of complexity of each study group and carry out a cost-effectiveness study.

METHODOLOGY: DESIGN: Clinical trial, randomized, placebo-controlled and double-blind, with two parallel groups The active treatment will be vitamin D (Hydroferol soft capsules of 0.266 mg). The placebo will consist of a tablet with the same external characteristics and with the same treatment scheme but which will not contain any vitamin D active ingredients.

Inclusion criteria: Adult patients admitted to the Respiratory/Internal Medicine Unit of Santiago hospital of the OSI Araba HUA for acute pneumonia and suffering from a vitamin D deficit (< 30 ng/ml) and a RT-PCR, in nasopharyngeal exudate, positive for SARS-CoV-2.

Exclusion criteria: 1)Patients taking any type of vitamin D supplement. 2)Patients with hypoparathyroidism. 3) Patients in whom the administration of vitamin D is formally contraindicated. 4) Patients who cannot take vitamin D orally.

OUR SIZE: In order to answer to the main objective (mortality reduction 21% versus 50% intervention and control group respectively), we will need a total sample of 108 evaluable subjects-54 patients per group (J Crit Care. 2018;44:300-5).Statistical power 90%,95% statistical significance with possible loss of follow-up of 5% of patients.

A recruitment period of about 12 months is needed.

STATISTICAL ANALYSIS: In order to answer to the main and secondary objectives (mortality and ICU admission), the Chi-square test will be performed and in the event that any of the frequencies is less than 5, the exact Fisher test will be used.

Depending on the distribution of the quantitative variables, the Student t-test for independent samples or the non-parametric Mann-Whitney U-test will be used, respectively.

The analysis criterion will be "by intention to treat". In all cases. The statistical significance will be 95%.

Inclusion Criteria:

• Admitted to the Respiratory or Internal medicine Units of Santiago hospital (HUA) due to pneumonia.
• Vitamin D deficiency (25(OH) defined by blood levels below 30 mg/ml.
• Possibility for observation during the treatment period.
• Signing of written consent (oral informed consent exceptionally).
• Positive PCR for diagnosis of sars-cov2 infection

Exclusion Criteria:

• Patients taking any type of vitamin D supplement.
• Patients with hypoparathyroidism.
• Pregnant or lactating women.
• Patients in whom the administration of vitamin D is formally contraindicated (see annex VI).
• Patients who at time of inclusion, cannot take vitamin D orally.

Triple-blind study, neither the patients, nor the researchers, nor those responsible for the statistical analysis will know the treatment that the patient is undergoing.