Since the outbreak of the new crown pneumonia epidemic in 2019, masks have played an important role in the prevention and control of the epidemic. Wearing masks scientifically can effectively prevent respiratory infectious diseases such as new coronary pneumonia and influenza. At the same time, the State Council’s joint prevention and control mechanism for the new crown pneumonia epidemic has also issued and continuously updated technical guidelines for the selection and use of masks for different groups of people to prevent new crown pneumonia.
As China’s epidemic prevention and control has entered the “post-epidemic era”, the shortage of masks and other anti-epidemic materials has been basically resolved, and some medical device manufacturers have begun to turn to the development of functional products such as “antibacterial and antiviral masks”. . Related issues such as how to effectively verify related products and whether they can achieve the claimed functions have aroused industry discussions and social concerns. The Device Evaluation Center of the State Food and Drug Administration has conducted many investigations and studies on this issue, and held expert seminars to solicit opinions from relevant industry experts. Experts participating in the discussion include experts in the research and development and production of meltblown cloth, clinical infection control, virology, disease control, disinfection, protection product testing, drug review and other fields.
Current situation of “antibacterial and antiviral” mask products
There are currently non-medical masks claiming to be “antibacterial and antiviral” on the market, usually through blending, spraying, etc. All kinds of antibacterial agents are added in the method, and the main additives include nano-titanium dioxide, nano-silver, quaternary ammonium salt, copper ion/copper oxide, traditional Chinese medicine extract, etc.
Focus on the safety and effectiveness of such products
(1) Product safety
In terms of the combination of antibacterial agents and masks, the current antibacterial agents are mainly added to the meltblown cloth layer by particle blending, powder/solution spraying, etc. However, the differences in the method and process of mixing the antibacterial agent into the meltblown cloth lead to the possibility of it falling off and entering the respiratory tract and bringing further risks. It is necessary to establish a reliable method to fully evaluate the falling off of the antibacterial agent and the risks caused by it.
In terms of the toxicity of antibacterial agents, the current evaluation methods and evaluation content are still immature or have not been established effectively. For example, for some masks containing antibacterial substances, it is necessary to fully evaluate the toxicological risk of long-term inhalation of antibacterial agents after shedding, but the relevant applicants have not fully evaluated such risks, and have not identified the risk of long-term inhalation of normal people; Some mask products also achieve claimed effects by adding nanosilver or other nanomaterials, but a systematic method for evaluating the toxicological risks of nanomaterials is still being established.
(2) Product effectiveness
In terms of filtration principle, the barrier of masks to bacteria, viruses and other tiny particles mainly relies on electrostatic adsorption (electret). handling to make it electrified), and the aid of mechanical barriers. Studies have shown that different types of antibacterial agents and different addition processes may have a certain negative effect on the electrostatic adsorption effect of meltblown cloth, resulting in the attenuation or premature attenuation of its filtering effect, which needs further verification.
In the aspect of in vitro research on antibacterial and antiviral, on the one hand, for “antibacterial/bacteriostatic” research, the current detection method mainly refers to the “antibacterial and antibacterial” of conventional static disinfection products (wet wipes, diapers, textiles, etc.) “Evaluation method, and mask products are different from conventional disinfection products due to their continuous and dynamic gas inhalation, and the conventional “antibacterial/bacteriostatic” evaluation method is not suitable for mask products. For example, the commonly used antibacterial/antibacterial evaluation methods are generally elution or static culture, etc. Such evaluation methods do not take into account the actual continuous airflow inhalation of masks, and cannot fully reflect the actual functioning of such products. On the other hand, for “antiviral” research, there is currently no clear definition of “antiviral”, scientific evaluation methods and generally recognized criteria for such products, and relevant research is still relatively weak.
In terms of the clinical effectiveness of the product, currently the applicant’s verification of the purpose of “reducing the risk of secondary infection” through “antibacterial/antiviral” is generally conducted through in vitro tests, and there is no clinical data to show that this type of product is used. It can reduce the infection rate or “reduce the risk of secondary infection”, and the effectiveness of application in actual clinical conditions needs further research.
The Center for Device Evaluation of the State Food and Drug Administration pointed out that at present, under the premise that the clinical effectiveness of such mask products has not been fully verified, the addition of antibacterial agents introduces new risks. , the risk-benefit ratio of continuous and long-term use of such products is insufficient, and it does not yet have significant clinical significance. More systematic and in-depth research is needed on product effectiveness and safety.