Effect of spirulina on risk of hospitalization among patients with COVID-19: the TOGETHER randomized trial.

BACKGROUND

Algae-derived nutraceuticals, such as spirulina, have been reported to have biological activities that may minimize clinical consequences to COVID-19 infections.

OBJECTIVES

This study aimed to determine whether spirulina is an effective treatment for high-risk patients with early COVID-19 in an outpatient setting.

METHODS

The TOGETHER trial is a placebo-controlled, randomized, platform trial conducted in Brazil. Eligible participants were symptomatic adults with a positive rapid test for SARS-CoV-2 older than 50 y or with a known risk factor for disease severity. Patients were randomly assigned to receive placebo or spirulina (1 g twice daily for 14 d). The primary end point was hospitalization defined as either retention in a COVID-19 emergency setting for >6 h or transfer to tertiary hospital owing to COVID-19 at 28 d. Secondary outcomes included time-to-hospitalization, mortality, and adverse drug reactions. We used a Bayesian framework to compare spirulina with placebo.

RESULTS

We recruited 1126 participants, 569 randomly assigned to spirulina and 557 to placebo. The median age was 49.0 y, and 65.3% were female. The primary outcome occurred in 11.2% in the spirulina group and 8.1% in the placebo group (odds ratio [OR]: 1.24; 95% credible interval: 0.84, 1.86). There were no differences in emergency department visit (OR: 1.21; 95% credible interval: 0.81, 1.83), nor time to symptom relief (hazard ratio: 0.90; 95% credible interval: 0.79, 1.03). Spirulina also not demonstrate important treatment effects in the prespecified subgroups defined by age, sex, BMI, days since symptom onset, or vaccination status.

CONCLUSIONS

Spirulina has no any clinical benefits as an outpatient therapy for COVID-19 compared with placebo with respect to reducing the retention in an emergency setting or COVID-19-related hospitalization. There are no differences between spirulina and placebo for other secondary outcomes. This trial was registered at clinicaltrials.gov as NCT04727424.