FDA Reclassifies VHP to Category A: What It Means for Medical Device Manufacturers

In January 2024, the FDA formally reclassified vaporized hydrogen peroxide (VHP) sterilization to Category A — the designation reserved for established sterilization methods with a well-characterized body of scientific evidence. This places VHP alongside steam, dry heat, ethylene oxide, and radiation as a recognized terminal sterilization modality.

For medical device manufacturers, this reclassification has immediate and practical significance.

What Category A Means

FDA categorizes sterilization methods into three tiers. Category A represents methods with extensive published literature, validated biological indicators, and established regulatory pathways. Category B covers methods with a developing evidence base. Category C applies to novel approaches still undergoing foundational research.

VHP's elevation to Category A means the FDA no longer considers it an emerging technology. It is established science — with the regulatory pathway clarity that designation carries.

Implications for Device Manufacturers

The practical impact is straightforward: manufacturers seeking 510(k) or PMA clearance for devices sterilized by VHP now operate within a well-defined regulatory framework. The burden of demonstrating method suitability is reduced, though process-specific validation remains required.

For manufacturers currently using ethylene oxide (EtO), the timing is significant. EPA emission reduction mandates are accelerating the transition away from EtO. VHP's Category A recognition provides a validated alternative with a clear regulatory pathway — not as an experimental substitute, but as an established peer.

The Validation Heritage

PuroGen has developed VHP-based sterilization systems for over three decades. The SteriFlex platform — PuroGen's programmable VHP sterilization system — was designed from inception within the constraints of regulatory validation. The FDA's reclassification does not change PuroGen's methodology; it confirms it.

Every SteriFlex system ships with complete IQ/OQ/PQ documentation, validated biological indicator protocols, and process parameters designed for regulatory submission. This has been the standard since the platform's origin — not because Category A was anticipated, but because validation-first design produces systems that are inherently ready for whatever regulatory designation applies.

What This Does Not Change

Category A recognition is a regulatory milestone, not a technical one. The science of VHP sterilization has not changed. The mechanism — microbial inactivation through gas-phase hydrogen peroxide at controlled concentrations, temperatures, and exposure times — remains the same process PuroGen has been validating and refining for three decades.

What has changed is clarity. Manufacturers evaluating sterilization alternatives can now make decisions with the confidence that VHP occupies the same regulatory standing as the methods they already use.

Looking Forward

The convergence of EPA pressure on EtO, FDA recognition of VHP, and ISO 22441 standardization creates an environment where validated VHP sterilization transitions from alternative to standard practice. Manufacturers who begin validation now will be positioned ahead of the inevitable demand.