This randomized controlled trial will focus on the effects of early oral nutritional supplementation on immune function in elderly patients with mild to moderate COVID-19 on maintenance hemodialysis. The purpose of this study is to determine whether early oral nutritional supplementation can improve immune function and clinical outcomes.

COVID-19 is in the midst of a global pandemic. Elderly patients are often susceptible and at high risk. Elderly patients on maintenance hemodialysis are often accompanied by a variety of complications, malnutrition is a common complication with an incidence of 23-73%. Due to a variety of risk factors, COVID-19 infection tends to develop into severe disease, and it takes longer for nucleic acid to turn negative.

This randomized controlled trial will focus on the effects of early oral nutritional supplementation on immune function in elderly patients with mild to moderate COVID-19 on maintenance hemodialysis. The purpose of this study is to determine whether early oral nutritional supplementation can improve immune function and clinical outcomes.

Inclusion Criteria:

1. Aged 60 and above;
2. Patients receiving hemodialysis with clinically confirmed end-stage renal disease
3. Positive diagnosis of COVID-19 by RT-PCR nasopharyngeal swab was classified as mild or moderate type
4. Patients who can eat on their own;
5. Patients had good compliance, fully understood the study content and signed informed consent.

Exclusion Criteria:

1. Contraindications of oral nutritional supplementation, such as intestinal obstruction and intestinal ischemia.
2. In an unstable state of vital signs such as shock.
3. In acute pancreatitis, cholecystitis acute attack period and 3 months after the last attack
4. Patients with moderate to severe cognitive impairment or mental diseases;
5. People who are allergic to intestinal nutrients
6. Refuse oral nutritional supplements