key: cord-0960162-pvhe1ff4
authors: Brun, D.; Curti, C.; Mekideche, T.; Benech, A.; Hounliasso, I.; Lamy, E.; Castera, C.; Rathelot, P.; Vanelle, P.
title: Stockpiled N95 respirator/surgical mask release beyond manufacturer-designated shelf-life: a French experience
date: 2020-08-01
journal: J Hosp Infect
DOI: 10.1016/j.jhin.2020.07.032
sha: a091157ee0b8cbb7bdd3a9f095a90c4a996439b4
doc_id: 960162
cord_uid: pvhe1ff4

BACKGROUND: To reduce the shortage of N95 respirators and surgical masks during the COVID-19 pandemic, stockpiled equipment beyond its expiry date could be released. AIM: Centralized testing of batches of expired surgical masks and N95 for safe distribution to hospital departments saving users time. METHODS: Tests of compliance with health authority directives were developed and carried out on 175 batches of N95 masks and 31 batches of surgical masks from 12(th) March 2020 to 16 April 2020. Five quality-control tests were performed on batch samples to check: packaging integrity, mask appearance, breaking strength of elastic ties and strength of nose clip test, and face-fit. FINDINGS: Forty-nine per cent of FFP2 mask batches were compliant with directives, 32% of batches were compliant but with some concerns and 19% of batches were non-compliant. For surgical masks, 58% of batches were compliant, 39% of batches compliant but with concerns and 3% of batches were non-compliant. CONCLUSION: The main areas of non-compliance were the breaking strength of the elastic ties and the nose clip but these alone were not considered to make the masks unacceptable. Only mask appearance and face-fit results were decisive non-compliance criteria.

Background: To reduce shortage of N95 respirators and surgical masks during COVID-19 pandemic, stockpiled equipment beyond its expiry date could be released. Aim: Centralized testing of batches of expired surgical masks and N95 for safe distribution to hospital departments saving users time. Methods: Tests of compliance with health authority directives were developed and carried out on 175 batches of N95 masks and 31 batches of surgical masks from 12/03/2020 to 16/04/2020. Five quality control tests were performed on batch samples to check: packaging integrity, mask appearance, breaking strength of elastic ties and strength of nose clip test, and face-fit. Findings: 49% of FFP2 mask batches were compliant with directives, 32% of batches were compliant but with some concerns and 19% of batches were non-compliant. For surgical masks, 58% of batches were compliant, 39% of batches compliant but with concerns and 3% of batches were non-compliant. Conclusion: The main areas of non-compliance were the breaking strength of the elastic ties and the nose clip but these alone were not considered to make the masks unacceptable. Only mask appearance and face-fit results were decisive non-compliance criteria.

Keywords: N95 respirators, surgical masks, COVID-19, quality control 1. Introduction:

The risk of pathogen transmission can be reduced by using a disposable filter respiratory protection against particles and aerosols [1]. There are several types of single-use masks providing different levels of protection. Surgical masks stop at least 80% of aerosols and protect the people around the user. N95 Filtering Facepiece Respirators (American equivalent of European FFP2 masks) stop at least 94% of aerosols and protect the wearer against infections. However, the coronavirus 2019 (COVID-19) pandemic has led to a drastic shortage of personal protective equipment worldwide [2] .

Following the H1N1 influenza epidemic health crisis in 2009, France constituted a safety stock of one billion surgical masks and of 799.9 million FFP2 masks (equivalent to N95). In 2013, there was a change of approach to stock management which was found too expensive.

The new management approach generated a shortage of surgical and FFP2 masks in hospitals right from the beginning of the COVID-19 health crisis, exposing caregivers to the highest risk of contamination.

Driven by the urgent need for masks to prevent the spread of COVID-19, stockpiled FFP2/N95 and surgical masks that had passed their manufacturer-designated shelf-life were released. Given the prevailing emergency, the usual standards for the control of medical devices were adapted to the financial and material resources available.

In the United-States, the Center for Disease Control (CDC) and Prevention published recommendations [3] . stating that prior to using the respirator in the workplace, users should take four precautionary measures: three visual tests, and one user seal check. CDC is also currently conducting a study to evaluate stockpiled N95 from several geographically scattered facilities.

In France, the release of expired batches of FFP2/N95 and surgical masks was the responsibility of the Agence Régionale de Santé (ARS, the regional public authority responsible for the implementation of health policy in a given region). According to French Health Ministry directives [4] , four verifications, similar to the CDC tests, were required on the FFP2 mask batches before release: packaging integrity verification, mask appearance verification, breaking strength test on elastic ties and strength test on nose clip, and face-fit test. These tests, contrary to CDC recommendations, were not to be done by the users.

Ministerial directives recommended that health structures use existing resources such as quality control laboratories to perform the tests. From each batch, a sample of 15 FFP2/N95 masks and 12 surgical masks was taken for testing. Some samples were used for several tests. Except for the face-fit test performed only on 3 FFP2/N95 masks by batch, identical testing was carried out on both types of masks. For each batch, 3 masks were kept stored in the laboratory.

The primary and secondary producers' packaging integrity was visually verified, searching in particular for alterations (discoloration, cracks, moisture, tears) in the packaging.

For each batch, 10 samples were checked when possible.

Mask appearance verification was inspected visually under an inspection machine with black and white background. A check for deterioration (discoloration, tears, decomposition) was carried out on 10 samples which can be used for other tests.

The breaking strength of the elastic ties was evaluated with an Instron 3343 dynamometer and strength transducer (INSTRON 02062 Massachusetts, USA) with a capacity of 100

Newtons. The apparatus was connected to a DELL Optiplex GX520 computer equipped with data processing software (Bluehill). The mask was placed between fixed jaws of the dynamometer and the elastic ties between movable jaws. Elastic strain was applied at a 500mm/min speed, as soon as an elastic broke under the extension, a measurement was recorded and the breakage site noted. Before each measurement set, 3 reference masks (from valid batches) were tested. The compliance limit was the lowest value reduced by 10% from a reference measurement set. For each batch, 9 samples were checked.

The strength of the nose clip was tested manually by performing 10 twists along the full length of the clip. The same 9 samples per batch and for the elastic tie breaking strength test were checked, and are valid reference mask was tested per batch. (Table I) The visual inspection of masks revealed a non-compliance with the ministerial directives for 7% of FFP2 mask batches and 3% of surgical mask batches. In the majority of these batches, the nose foam crumbled easily when touched (Figure 1) . At the establishment's request, compliance testing on its batches stopped when this result was obtained. Another establishment asked us to cover the foam with adhesive tape and to continue testing. One batch from a donation to a hospital was suspected of being counterfeit. An N95 mask has to be carry a brand name, a National Institute for Occupational Safety and Health (NIOSH) logo, a TC approval number, a filter class and filter efficiency level and a model number [6] . On the suspect batch, all the required data except the NIOSH logo and the filter class and efficiency level were missing (Figure 2 ). The face-fit test was also negative for this batch.

The breaking strength test of the elastic ties showed that 63% of the FFP2/N95 mask batches were compliant and 37% were non-compliant with the ministerial directives. Among the non-compliant batches, there were 3 categories: 17% of batches with 1 to 3 non-compliant samples, 7% of batches with 4 to 6 non-compliant samples and 13% of batches with 7 to 9 non-compliant samples (Table I) . Two different break points were observed and noted: junction point between elastic and mask, and middle of elastic. For the surgical masks, this test revealed non-compliance with the ministerial directives: there were 10% of batches with 1 to 3 non-compliant samples, 6% of batches with 4 to 6 non-compliant samples and 23% of batches with 7 to 9 non-compliant samples.

The strength test on the nose clip test revealed that 9% of batches were non-compliant with the ministerial directives: either the nose clip broke from the first twists, or the nose clip broke during the last twists. Moreover, 2% of the batches had no nose clip and therefore were not checked on this criterion.

On the face-fit test, 16% batches were non-compliant with the ministerial directives.

Batches were considered non-compliant as soon as the experimenter experienced a sweet taste during at least one exercise of the test. For 1% of the batches, a fourth experimenter performed the test to avoid errors.

Since the beginning of the COVID-19 health crisis, there has been a dramatic shortage of surgical and FFP2/N95 masks, leaving health caregivers exposed to a high risk of infection.

The French Health Ministry sent directives to hospitals, instructing them to test masks whose expiry date had passed and to extend their use. In response to these directives, our laboratory specially designed several tests and adapted INRS guidelines [5] for the face-fit test.

Of the 206 batches assessed, 81% of FFP2/N95 mask batches and 97% of surgical mask batches were found sufficiently compliant with the ministerial directives. Most cases of noncompliance involved the nose clip and elastic ties, but were not considered to preclude use.

However, non-compliance involving the face-fit could lead to contamination, non-compliance involving mask appearance would indicate poor stare of preservation.

The test on elastic tie to breaking strength yielded 3 categories of batches. Batches containing 1 to 3 non-compliant samples need to be considered fragile in terms of their elastic ties. Batches containing 4 to 6 non-compliant samples warrant precautionary measures.

Batches containing 7 to 9 non-compliant samples are not recommended for use. Nevertheless, depending on the breaking point of the elastic, establishments may still be able to use the mask: if the breaking point is at the junction between the elastic and the mask, the mask can be used provided this point is reinforced with staples.

In addition to revealing batches that were insufficiently airtight, the face-fit test revealed other characteristics that could make them unsatisfactory. Some batches had strong musty 9 odors or strong chemical odors which could indicate given poor storage conditions. One batch had very poor breathability, preventing its use.

Given the health emergency represented by this crisis, a compromise had to be made between performing lengthy tests to the usual standards and the speed to obtain rapid results.

To avoid cases such as that of Reunion Island, where masks appearing moldy were delivered to hospitals, meticulous testing must be applied. In our laboratory, although utmost care was given to all tests, each result was obtained within 6 working hours.

The fact that all testing required by the ministerial directives was grouped together in the same laboratory provided a comprehensive picture. This made it possible to quickly identify the various non-compliances that commonly arose, but also to check masks donated to hospitals, the origin of which could not always be verified. Thus, counterfeit masks were quickly suspected, then confirmed by the absence of regulatory data.

Because of the lack of comprehensive guidelines for assessing the quality and efficiency of these masks, the Health Ministry published its two directives with low requirements in a crisis context. It would be wise to take advantage of this experience to create a national standard protocol that would harmonize quality controls by different laboratories and enhance the rapid response to such testing accords in a health crisis. The Ministry should also take advantage of this critical situation to modify the national stock management policy in two directions: by increasing safety stocks as well as production autonomy to reduce worldwide dependence in one manufactory country. This would avoid recourse to inadequate solutions appearing during health crises, such as manufacturing paper or cloth masks, not officially recommended for use due to scientific evidence that they do not protect against viral contamination [7, 8] .

This work suffers from several limitations. First, the urgency of the health situation forced this study to be conducted over a short period of time. Moreover, during the epidemic, there was a lack of material and time needed to control mask conformity with regards to standards. From our knowledge, mask quality control in an emergency context has not been described before and required the development of new techniques. The protocol we described cannot guarantee compliance to standards but allows the detection of critical noncompliance.

The Covid-19 health crisis led to a shortage of respiratory protection masks but also of all personal protective equipment. The development of emergency quality control protocols for equipment such as gloves or over-coats would allow the rapid release of expired batches.

Beyond this epidemic, quality control protocols could also allow the rapid identification of counterfeit protective equipment.

Of the 175 batches of FFP2/N95 masks and 31 batches of surgical masks tested by our laboratory in thirty-six days, 81% of FFP2 mask batches and 97% of surgical mask batches were released for use. The testing prevented 19% of defective batches of FFP2/N95 masks and 3% of defective batches of surgical masks being delivered to health care personnel. Even in a health crisis context, it is vital to take the time to perform the quality checks that guarantee the safety of personal.

Under the conditions of extreme tension and lack of time experienced by hospital staff in contact with COVID-19 patients, the quality control of stockpiled N95 respirators and surgical masks should not be verified by the users themselves. Pharmaceutical expertise, for

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