What is the treatment for Coronavirus NL63 (Human Coronavirus NL63) infection?

Treatment for Human Coronavirus NL63 Infection

Treatment for Human Coronavirus NL63 is primarily supportive and symptomatic, as there is no specific antiviral therapy approved for this infection, though remdesivir shows promise in research settings and may be considered in severe cases, particularly in immunocompromised patients.

Supportive Care (Primary Treatment Approach)

Symptomatic Management

• Use paracetamol as the preferred antipyretic for fever and symptom relief, taken only while symptoms are present rather than routinely 1, 2
• Honey is recommended as first-line treatment for cough in adults with HCoV-NL63 infection 1, 2
• If cough becomes distressing despite simple measures, consider short-term use of codeine linctus, codeine phosphate tablets, or morphine sulfate oral solution 1, 2
• For patients with dyspnea and increased respiratory secretions, use selective (M1, M3) receptor anticholinergic drugs to reduce secretion, relax airway smooth muscle, and improve pulmonary ventilation 3, 4

Respiratory Support and Positioning

• Teach controlled breathing techniques, including pursed-lip breathing to manage breathlessness 1, 2
• Patients should sit upright to increase peak ventilation and lean forward with arms bracing to improve ventilatory capacity 1, 2
• Avoid lying flat on the back, as this makes coughing ineffective 1, 2
• Relax and drop shoulders to reduce anxiety-related hunched posture that worsens breathlessness 1, 2

Nutritional and Fluid Support

• Ensure adequate hydration with regular fluid intake, limited to no more than 2 liters per day 1, 2
• Provide protein-rich foods with ideal energy intake of 25-30 kcal/(kg·day) and protein intake of 1.5 g/(kg·day) 3, 4, 1
• For patients with nutrition risk scores ≥3 points, increase protein intake through oral supplements 2-3 times daily (≥18g protein/time) 4

Oxygen Therapy and Advanced Respiratory Support

Escalating Oxygen Delivery

• Provide effective oxygen therapy based on severity: nasal catheter, mask oxygen, high flow nasal oxygen therapy (HFNO), non-invasive ventilation (NIV), or invasive mechanical ventilation 4
• Consider Extracorporeal Membrane Oxygenation (ECMO) for patients with refractory hypoxemia unresponsive to protective lung ventilation 4

Antiviral Considerations

Experimental Antiviral Agents (Research Evidence Only)

While no antivirals are FDA-approved specifically for HCoV-NL63, research provides important insights:

• Remdesivir shows the most promise in cell culture models, with higher binding affinity to HCoV-NL63 RdRp (LibDock score 151) compared to SARS-CoV-2 (LibDock score 135), and demonstrates potent inhibition of viral replication without resistance development 5
• Favipiravir also inhibits HCoV-NL63 replication in cell culture, though less potently than remdesivir 5
• Combining remdesivir or favipiravir with interferon-alpha results in synergistic effects 5
• Pegylated interferon-alpha (PEG-IFN-α) can eliminate HCoV-NL63 virus, though one case report showed fatal outcome despite viral clearance in an immunocompromised patient 6

Important caveat: These agents are not approved for HCoV-NL63 and should only be considered in severe cases, particularly in immunocompromised patients, on a case-by-case basis with informed consent 6, 5

Immunomodulatory Therapy (Severe Cases Only)

• For patients with rapid disease progression or severe illness, methylprednisolone 40-80 mg per day can be considered, not exceeding 2 mg/kg daily 4
• Corticosteroids should be used cautiously and typically for short periods (3-5 days) according to the degree of dyspnea and progression on chest imaging 4
• Do not use corticosteroids for mild cases, as they may prolong viral clearance and increase mortality in non-severe disease 1

Prevention of Complications

Gastrointestinal Protection

• Use H2 receptor antagonists or proton pump inhibitors in patients with gastrointestinal bleeding risk factors (mechanical ventilation ≥48 hours, coagulation dysfunction, renal replacement therapy, liver disease) 3, 4

Thromboembolism Prophylaxis

• Evaluate the risk of venous embolism and use low-molecular-weight heparin or heparin in high-risk patients without contraindications 3, 4

Septic Shock Management

• For septic shock, recognize early and administer vasopressors when shock persists after fluid resuscitation, with norepinephrine as first choice 4

Antibiotic Use

• Avoid blind or inappropriate use of antibacterial drugs unless there is clear evidence of secondary bacterial infection 4, 1, 2
• If bacterial infection cannot be ruled out, consider antibiotics effective against community-acquired pneumonia (amoxicillin, azithromycin, or fluoroquinolones) for mild cases with suspected bacterial co-infection 4

Monitoring and Red Flags

Essential Monitoring

• Monitor vital signs including heart rate, pulse oximetry, respiratory rate, and blood pressure regularly 1, 2
• Perform regular assessment of blood routine, organ function, and chest imaging 4
• Healthcare personnel should perform daily follow-up through face-to-face visits or phone interviews 1

Immediate Hospital Evaluation Required If:

• Worsening breathlessness or respiratory rate ≥30 breaths/min 1
• Oxygen saturation <94% on room air (or ≤93% at rest) 1
• Persistent chest pain 1
• Confusion or inability to stay awake 1
• Progressive worsening of symptoms despite home care 1

Isolation and Infection Control (Mild Cases at Home)

• Isolate in a well-ventilated single room with bed distance of at least 1 meter from others 3, 1
• Wear medical mask when coughing or sneezing, or cover with paper towel and bent elbow 3, 1
• Clean and disinfect household articles using 500 mg/L chlorine-containing disinfectant frequently every day 3, 1
• Caregivers should wear N95 masks when in the same room with patients 3, 1
• Avoid sharing personal items (toothbrush, towel, tableware, bed sheets) 3, 1

Critical Clinical Pearls

HCoV-NL63 can cause fatal outcomes in immunocompromised patients despite being typically mild in healthy individuals, as demonstrated by a case of fatal ARDS in a leukemia patient despite successful viral elimination 6. This emphasizes the need for aggressive supportive care and close monitoring in this population.

All hospitalized patients with HCoV-NL63 in one Australian study had severe lower respiratory tract disease, with 81% diagnosed with LRT disease, 56% with abnormal chest X-rays, and 38% with co-infections 7. This highlights the importance of screening for secondary pathogens and providing appropriate respiratory support.

Fever typically peaks around day 5 after exposure, requiring particularly close monitoring during this critical period 1, 2.