Monitoring Cleanrooms for Vaccine Manufacturing Facilities

Environmental Monitoring (EM)

Monitoring for microbial and particulate contaminates of cleanrooms and associated clean zones for sterile processing is to determine the compliance of quality standards for manufacturing vaccines and other viral medicines. In this article, we will examine how optimizing environmental monitoring for medical production cleanrooms. The purpose is constant monitoring of the air quality and sends alerts when outside of defined parameters. There are guidelines from the World Health Organization (WHO) for the production of quality biological products.

typical clean room setup

The monitoring system is part of the equipment that services cleanrooms to maintain them in a state of control. There are two testing methods used.

1) Non-viable testing measures the number of total particulates within a cleanroom that do not contain living organisms. These non-viable particles, however, can contribute to the spreading of viable particles.

2) Viable testing measures the number of particulates within a cleanroom that contain bacteria, yeast, molds etc. Not only air should be monitored but also surfaces within the cleanroom.

Pharmaceutical manufacturing produces a variety of biological products that run the risk of microbial contamination through numerous sources. Its viability as a pharmaceutical is affected by several processing steps.

There are two types of pharmaceutical products currently being manufactured. These are sterile and non-sterile products. For example, parenteral or injectable drugs are included in the sterile category because they enter directly into the bloodstream. International standards in the manufacturing of sterile products must be followed to limit microbial contamination and safeguard the quality of the products.

Two methods are used that ensure the safety of sterile products.

Terminal sterilization. The filling and stoppering of product bottles under highly sterilized environmental conditions. Vials or bottles are then further sterilized through heat or UV radiation. In some instances, the drug and bottle still contain low biological contaminates.

Aseptic sterilization. All the components used are sterilized individually through prescribed methods at each step of production. Then, they are brought together in sterilized areas.

Both the sterilization method needs a highly controlled environment.

Environment plays a significant role in microbial contamination of pharmaceutical and biological products. The integrity of the products solely depends on the implementation of strict environmental conditions in the manufacturing area. To prevent contamination, you need a competent environmental monitoring system. This system should have identification, testing and a way to eliminate bioburden to keep the products safe.

Monitoring alerts the staff if any excursion from the cleanroom required parameters occurs.

To maintain the integrity of the cleanroom, a Clean Area Separation is required. A neutral area divided between the cleanroom and external environment to prevent cross-contamination. The aim is to maintain the sterilized air quality in the cleanroom. The appropriate airflow and a positive differential air pressure must be maintained between the cleanroom and the outside environment.

Positive differential air pressure acts as a barrier to prevent the entrance of external air to the cleanroom environment. It forces out the air to adjacent areas, which ensures outside air is not sucked inside carrying with it contaminants.

The ideal differential air pressure between the cleanroom and outside or the next lower cleanroom is at least 10-15 Pascals (Pa) which is equal to 0.03 to 0.05 inches of water gauge with the door is closed. When opened, outward air pressure must be enough to prevent the entry of contaminants from the external environment.

To find the right EM system for your cleanroom you should consider the following:

1.  Determine the environmental monitoring system is up to Good Manufacturing Practices (GMP) standards for vaccine manufacturing

2. Evaluate the effect of air differential pressure on the maintenance of a controlled environment for biopharmaceutical product manufacturing

3. Classify  specified  grades to  clean areas of local vaccine manufacturing  unit  based on world health   organization  (WHO)  Clean rooms standards

Part of the EM is Microbiological Surveillance that involves constant checking for airborne biological contaminants, on operators and surfaces. Such a program minimizes the viable microbial load (bioburden), and this monitoring gives data about the air filtering system efficiency.

Microbiological risks

The microbiological risk, or microbial risk, is defined as a possibility of occurrence of harm and the degree of damage to the biological products. A risk as identified by the WHO is “an event in the production, control and supply of a drug which has potential an adverse health effect”.

Intrinsic or Extrinsic.

Intrinsic risks are from within the manufacturing system and influence the quality of the product. Its cause can be a mechanical problem or failure in the sterilization of manufacturing material, i.e. contaminated water for injection (WFI), active pharmaceutical ingredient (API), or final product. 

Extrinsic risks are those coming outside the manufacturing process, i.e. environment, personnel and surfaces. They pose a more significant problem than intrinsic risks. If these are not controlled, they compromise the quality of the product and can ultimately affect the patient.  

cleanroom delivery

Recognizing the hazard and its impact on product quality is critical to undertake a risk assessment. The application of risk assessment tools is an essential part of GMP procedures for environmental monitoring. The microbiological risk for drugs produced under high air quality conditions in pharmaceutical cleanrooms can be measured by the dispersion, transfer and accumulation of the contamination onto the drugs.

The risk assessment can be done in two-steps. These two steps will assess and attempt to minimize the microbiological risk in the in the cleanroom and related production line:

Step one is measuring the transmission of microorganism from all of the sources within the cleanroom premises.

Step two is to look at both air and surface contact contamination within the essential production sites.

The EM program must demonstrate control over both viable and non-viable particles found in critical areas of your operation. The procedures and protocols you have in place must ensure aseptic conditions throughout your vaccine production.

In truth, humans themselves are considered the primary source of contamination in classified areas due to different strains of bacteria and viruses already in our bodies. We use these microbiological organisms for our survival. To minimize constant endogenous emissions to the cleanroom production facilities, personnel should wear isolation equipment and always observe aseptic procedures.

working in PPE

So what is the best environmental monitoring methods for you?

Finding what to clean and monitor and where to concentrate these efforts is the beginning of maintaining your cleanroom. There are viable and non-viable contaminants that can exist in the cleanroom environment. Knowing both is important in understanding the asepsis of your cleanroom and operation.

The critical areas to monitor are:

Staff working in the cleanroom: People are the most obvious carriers of contaminants to the clean rooms. Personal Protective Equipment (PPE) and gowning routines as well as ensuring minimal skin contact with the products and cleanroom environment, reduce the risk.

Monitor your surfaces: Including worktops, floors, walls and equipment. It must be cleaned appropriately and regularly. Usually, regular monitoring for viable particle counts through the use of contact plates that will let you know about contaminants, as bacterial growth.

The air in your cleanroom facility: Parameters such as pressure, temperature and humidity are always controlled by HVAC control systems and continuously monitored. Therefore, the air samplers for both viable and non-viable particle monitoring must be maintained and calibrated regularly, ensuring the accuracy of data.

Here are the most effective methods of environmental monitoring in a cleanroom facility:

Sampling air through air samplers and settle plates.

Air samplers draw in air from the cleanroom environment and drawn over a media plate. The plate is incubated and indicates the number of particles per cubic feet or litre.

Settle plates are the standard passive air sampling method and use Petri dishes that contain sterile growth media (Tryptic Soy Agar). These plates are left open in the environment. Four hours is required for it to be exposed before they are removed and incubated.  However, measuring the contamination in the air is difficult with this form of passive air sampling. Therefore, it is recommended the use of a combined monitoring program that includes both passive and active air sampling.

Two Methods for Surface Monitoring.

Contact plates are for surface monitoring are prepared with a culture sample protruding above the sides of the dish. The plate is then pressed against the surface where possible viables are present. They will stick to the plate and present after incubation. Standardization of this method can be attained by using Contact Plate applicators.

The second method of sampling and monitoring on surfaces is using sterile swabs. These are swabbed over the target area before being transferred to the laboratory. The microorganisms can then be detected through the subculturing of any collected particles the swab picked up onto the swab disk. This is ideal if the surface area you are trying to sample is difficult to get to.

To ensure your personnel are cleared for entry into the cleanroom facility, you must make use of contact plates together with the correct gowning routine.

To see how effective your gowning program is, you can monitor your personnel by employing contact plates to assess any microbial contamination. The contact plates can monitor the areas of the body that were in contact with the sterile areas of the cleanroom.

Air Filtration

Using complex filter systems, which consist of thick, and thin filters and an air terminal unit with high-efficiency particulate air (HEPA) filters.

A vigorous and stringent environmental monitoring program can help in gathering critical data to prevent future contamination. It is necessary to ensure compliance with the latest standards and drives your productivity going forward, with minimizing production halt through contamination.

Corrective and Preventive Actions (CAPA)

CAPA is the recommended steps that take place when a breach of cleanroom monitoring values occurs.

Production, engineering, quality control, and quality assurance will benefit from the cleanroom functioning according to its specification, and each can contribute to the design and conduct of CAPA.

If high amounts of contaminants are present during operation, it can be isolated to minimize the risk of cross-contamination. If contaminants are present in the workspace of a particular operator, the hygiene, work practices, and training of the operator can be evaluated and improved.

When frequent contaminations occur but an investigation did not reveal the cause, aggressive efforts must be made to improve cleanroom function and prevent further incidents.

Environmental monitoring can be doubled to cover more areas to try to pinpoint the source, and assure that the cleanroom area is operating according to specifications.

With the effective CAPA programs observed, contaminations are decreased.

Companies that fail to conduct effective investigations and CAPA programs will waste precious resources through batch failures.

Once the CAPA is implemented, the time frame for completion of needed improvements should be followed, and persons or departments responsible for the corrective action identified. Responses to the CAPA should be recorded so when it occurs again, there is a standard procedure to counteract it.


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