Does the 28-day open vial policy apply to reconstituted anti-rabies vaccine (lyophilized) used for intradermal (ID) route in public health center (PHC) settings, or is session-based usage with same-day discard the recommended practice?

Rabies Vaccine Vial Usage: Session-Based Discard vs 28-Day Open Vial Policy

Reconstituted lyophilized rabies vaccine used for intradermal administration must be discarded at the end of the same vaccination session (6-8 hours maximum) and cannot be stored for 28 days, even under proper cold chain conditions. This is the correct operational practice for PHC settings.

Key Distinction: The 28-Day Open Vial Policy Does NOT Apply to Rabies Vaccine

The WHO's 28-day open vial policy applies to specific vaccines (like measles, polio, DTP) that remain stable after opening under proper storage conditions. Rabies vaccine is explicitly excluded from this policy due to its unique stability characteristics after reconstitution 1.

Evidence-Based Rationale for Same-Day Discard

Manufacturer and Regulatory Guidance

• The FDA-approved product labeling for Imovax Rabies (the lyophilized HDCV used for ID administration) explicitly states: "After reconstitution, immediately administer the full 1.0 mL amount of vaccine. If it cannot be administered promptly, discard." 2

• The reconstituted vaccine contains no preservative, making it susceptible to contamination and degradation once the vial is opened 2

International and Field Practice Standards

• Field experience from Thailand and India, where intradermal rabies vaccination has been extensively implemented since the 1980s, consistently demonstrates that "all reconstituted vaccine unused at the end of 6-8 hours must be discarded" 1

• A rural Thailand mission hospital study from 1984 documented safe storage of reconstituted vaccine for "repeated use" within the same day session, but not beyond 3

• Indian PHC implementation studies specifically note that vaccine wastage calculations account for same-session usage only, with no provision for multi-day storage 4

Operational Practice for PHC Settings

Session-Based Usage Protocol

• Reconstitute the lyophilized vaccine vial only when patients are present and ready for vaccination 1

• Use the reconstituted vaccine for all patients presenting during that vaccination session (typically 4-6 hours) 4, 1

• Discard any remaining reconstituted vaccine at the end of the session, not to exceed 6-8 hours after reconstitution 1

Vaccine Wastage Considerations

• Studies from Indian PHCs implementing intradermal rabies vaccination report approximately 20.8% vaccine wastage when following proper session-based protocols 4

• This wastage rate is acceptable and built into the cost-effectiveness calculations that still demonstrate 68% cost reduction compared to intramuscular regimens 1

• The economic benefit of intradermal administration far outweighs the wastage from same-day discard requirements 4, 1

Critical Safety Considerations

Why Extended Storage Is Prohibited

• Lyophilized rabies vaccines contain no preservatives after reconstitution, creating risk of bacterial contamination with extended storage 2

• The vaccine's potency and immunogenicity cannot be guaranteed beyond the immediate post-reconstitution period 2

• Rabies is virtually 100% fatal once clinical symptoms appear, making any compromise in vaccine efficacy unacceptable 1

Common Pitfalls to Avoid

• Never store reconstituted rabies vaccine overnight or between sessions, even under refrigeration - this violates both manufacturer guidelines and established field protocols 2, 1

• Do not confuse the 28-day open vial policy for other vaccines with rabies vaccine requirements - rabies vaccine has unique stability limitations 1

• Ensure adequate patient scheduling to minimize wastage - coordinate animal bite cases to present during designated vaccination sessions when possible 4

Programmatic Implementation Guidance

For State Government PHC Practice

• The current practice of discarding reconstituted vaccine after the same vaccination session (4-6 hours) is correct and should be maintained 4, 1

• Schedule rabies vaccination sessions strategically (e.g., specific days/times) to optimize vaccine utilization while maintaining safety standards 4

• User fees or government funding should account for the expected 20-25% wastage rate inherent in safe intradermal rabies vaccination programs 4

Quality Assurance Measures

• Train PHC staff that the 6-8 hour discard rule is non-negotiable for patient safety 1

• Document reconstitution time on each vial to ensure compliance with same-day discard protocols 4

• Never compromise on the discard timeline to reduce costs - the mortality risk of rabies far outweighs any economic savings from extended vial use 1