2022-01-19-世界卫生组织-WHO_calls_for_comments_on_the_revised_Target_Product_Profile_for_COVID-19_vaccines_6页_158kb

WHO Target Product Profiles for COVID-19 Vaccines Summary

Purpose of the Document

This document outlines the Target Product Profiles (TPPs) for COVID-19 vaccines developed by the World Health Organization (WHO). It serves to guide vaccine development, product licensing, and prequalification processes by identifying preferred and minimally acceptable characteristics of vaccines. The TPPs are intended to support decision-making regarding vaccine use, booster requirements, and distribution, particularly in low- and middle-income countries (LMICs).

Core Content

The TPP is a dynamic document that reflects the latest scientific and epidemiological understanding of the pandemic. It is based on the WHO Global Research and Innovation Forum and includes considerations for vaccine performance across various categories, including:

• Indication for use
• Contraindications
• Target population
• Safety and reactogenicity
• Efficacy measures
• Dose regimen
• Durability of protection
• Deployability (including route of administration, stability, co-administration, and presentation)
• Registration and prequalification
• Availability and scalability

Main Viewpoints

1. Preferred vs. Minimal Criteria

• Preferred Characteristics:

  • Should protect against symptomatic disease with an efficacy of ~70% and a lower 95% confidence interval ≥50%.
  • Should protect against severe disease with an efficacy of ~90% and a lower bound ≥70%.
  • Single-dose primary series is preferred, with low frequency of booster doses (e.g., yearly or less).
  • Non-parenteral route of administration (e.g., nasal spray) is preferred for ease of use and logistics.
  • High thermostability and storage at higher temperatures are strongly preferred to improve distribution.
  • Multi-dose presentation is preferred for ease of use in vaccination campaigns.
  • Prequalification by WHO is preferred to ensure quality, safety, and efficacy.
  • Availability to LMICs with technology transfer and firm developer commitment is a priority.

• Minimal Criteria:

  • Efficacy against symptomatic disease of ~50% with a lower 95% confidence interval ≥30%.
  • Efficacy against severe disease of ~70% with a lower bound ≥30%.
  • Two-dose regimen is acceptable, with booster doses permitted if necessary.
  • Any route of administration is acceptable, provided the vaccine is safe and effective.
  • Stability for at least 2 weeks at 2-8°C is required.
  • Multi- or mono-dose presentations are acceptable.
  • Meets WHO Emergency Use Listing (EUL) criteria.

2. Flexibility and Prioritization

• The TPP emphasizes that a vaccine's profile may be sufficiently superior in one category to outweigh failures in another, provided it meets the critical characteristics.
• Vaccines that fail to meet multiple critical characteristics are unlikely to pass WHO's case-by-case assessments.

3. Programmatic Suitability

• The WHO Prequalification (PQ) process includes Programmatic Suitability for Prequalification (PSPQ) criteria, which assess the vaccine's suitability for use in LMICs.
• These criteria include logistical feasibility, cost-effectiveness, and scalability of production.

Key Information

• TPP Development: The document was revised in January 2022 to reflect updated knowledge about vaccine use, variants, and feasibility.
• Use in Emergency Situations: The minimally acceptable profiles align with emergency use authorization (EUL) or licensure standards.
• Future Revisions: The TPP may require further review and revision as new scientific evidence emerges.
• Impact Modelling: Modelling the impact of vaccines with different efficacy profiles under various immunization strategies and epidemic stages is a high priority to refine desired characteristics.

Conclusion

The WHO Target Product Profiles for COVID-19 vaccines provide a comprehensive framework for vaccine development, licensing, and distribution. They prioritize global accessibility, safety, efficacy, and logistical feasibility, especially in LMICs. The profiles are flexible, allowing for trade-offs between different characteristics, but emphasize the importance of meeting critical standards to ensure WHO prequalification and favorable outcomes in public health programs.