COVID-19 Reinfection Immunity Analysis

Core finding: Prior infection provides partial, temporary protection but does NOT prevent reinfection, especially with new variants.

⚠️ 1. Limited and Waning Protection

• Pre-Omicron variants: ~81% reinfection protection for 6-8 months
• Omicron-era infections: Only ~54% protection, dropping to <30% after 9-12 months
• Hybrid immunity (infection + vaccination) offers strongest protection

🛡️ 2. Protection Against Severe Disease

• Pre-Omicron infection: ~98% protection from severe outcomes
• Omicron infection: Near 100% protection with no observed waning

⏳ 3. Reinfection Risk Factors

• Variant evolution (e.g., new Omicron subvariants)
• Time since infection (sharp decline after 6 months)
• Infection severity and immune status
• Age and comorbidities (higher risk for 65+ and immunocompromised)

📊 Protection Duration by Variant

Protection Type	Pre-Omicron Infection	Omicron Infection
Any Reinfection	~81% (6-8 months)	~54% (wanes rapidly)
Symptomatic Reinfection	~87% (stable)	~45% (sharp decline)
Severe Disease	~98% (durable)	~100% (no waning)

💉 CDC Guidance for Previously Infected

1. Get updated 2024-2025 vaccine (boosts hybrid immunity)
2. Wait ≈3 months post-infection before vaccination
3. High-risk groups should prioritize vaccination

💎 Key Conclusion

COVID-19 infection does not confer complete or permanent immunity. Reinfections are increasingly common with viral evolution. Vaccination remains essential for durable protection against severe outcomes.