This trial was a randomized, double-blind, placebo-controlled, loading phase III clinical study.

This test is in the new type of coronavirus infection therapy and 10 (trial version) "and" new coronavirus pneumonia antiviral drug clinical trial technical guidelines (try out) ", on the basis of according to the results of the phase I and phase II clinical study to set up an experimental group and a placebo group, experimental group on the basis of medicines for load test, The control group was loaded with placebo as the base treatment. A planned cohort of 144 patients with Post-COVID-19 (120 +20% dropped out) was randomly assigned in a 1:1 ratio to the experimental group or the placebo group. Mepozumab or placebo was intravenously infused at a dose of 0.2 mg/kg on day 1 (D0). If the clinical symptoms of Post-COVID-19 were not relieved (remission was defined as a decrease in the Post-COVID-19 composite score for at least 2 days), an additional dose of 0.2 mg/kg was administered on day 7 after the first dose, and the actual dose was calculated according to the body weight of the subject. The participants were asked to record the clinical symptoms of Post-COVID-19 daily during the trial. The absent clinical symptoms were evaluated as "zero (none)", and the present clinical symptoms were recorded until they returned to normal (score: zero), which lasted for at least 2 days. On the 28th day (D28±3) after the first dose, the subjects were required to return to the study center again, return their diary cards, and complete each exit examination. If a participant stops the trial early for various reasons, laboratory testing is required to complete the efficacy and safety assessment. During the trial, the subjects were treated according to the type and severity of adverse events according to the clinical diagnosis and treatment standards.

Inclusion Criteria:

1. Age 18 to 84 (including 18 and 84), male and female
2. Patients had been infected with 2019-ncov and had at least one symptom of Post-COVID-19 after infection, such as insomnia, memory loss, smell change, taste change, fatigue or fatigue, headache, chest pain, muscle/joint pain, shortness of breath, cough, palpitation, arrhythmia, and aggravation of the primary disease
3. According to the Post-COVID-19 Clinical symptom assessment form , the total symptom assessment score of the subjects was ≥2 before randomization
4. Agree to use highly effective birth control within 3 months of using the experimental drug
5. The subjects were able to communicate well with the investigators, understand and comply with the requirements of the study, and understand and sign the informed consent

Exclusion Criteria:

1. Patients with allergic constitution and known allergic to the test drug and its components

2. Patients who underwent surgery or chemotherapy or radiotherapy within 28 days before screening

3. Patients had a serious systemic disease, condition, or disorder, etc., that was deemed by the investigator to be inappropriate for participation in the study

4. Use of an anti-coronavirus treatment such as Paxlovid (nematavir/ritonavir packaged in combination) within three half-lives before the first dose or during the study period, About 18 h at t1/2), Azvudine tablets (about 9 h at t1/2), and monolavir capsules (about 3.3 h at t1/2) h), ambavirumab/romisivir injection (t1/2 about 45 days /75 days), COVID-19 human immunoglobulin (t1/2 about 3-4 weeks) or recovery plasma (t1/2 about 21 days), deuremidvir hydrobromide tablets (t1/2 about 4.80-6.95 hours), etc

5. At the time of screening, any of the laboratory test indicators meet the following criteria

1. ALT or AST >3ULN
2. Total bilirubin ≥2 ULN
3. White blood cell count > 2 ULN
4. Neutrophil absolute value<0.5×109/L
5. Platelet count < 80×109/L
6. eGFR <60 mL/min/1.73 m2 (calculated by CKD-EPI formula)

Note: For patients with connective tissue diseases such as systemic lupus erythematosus, Sjogren's syndrome, and inflammatory myopathy, including but not limited to the above three diseases, the value of this index was determined by the investigator

6. Weight ≤40 kg

7. Dizzy with needles and blood

8. Had participated in other drug clinical trials within 3 months before screening

9. Pregnant, lactating women or those with a positive pregnancy

10. Other factors that the investigators considered inappropriate for trial entry