There is currently not sufficient evidence to support the effectiveness of face shields for source control. In order to evaluate the comparative barrier performance effect of face masks and face shields, we used an aerosol generator and a particle counter to evaluate the performance of the various devices in comparable situations. We tested different configurations in an experimental setup with manikin heads wearing masks (surgical type I), face shields (22.5 cm high with overhang under the chin of 7 cm and circumference of 35 cm) on an emitter or a receiver manikin head, or both. The manikins were face to face, 25 cm apart, with an intense particle emission (52.5 L/min) for 30 s. The particle counter calculated the total cumulative particles aspirated on a volume of 1.416 L In our experimental conditions, when the receiver alone wore a protection, the face shield was more effective (reduction factor = 54.8%), while reduction was lower with a mask (reduction factor = 21.8%) (p = 0.002). The wearing of a protective device by the emitter alone reduced the level of received particles by 96.8% for both the mask and face shield (p = NS). When both the emitter and receiver manikin heads wore a face shield, the protection allowed for better results in our experimental conditions: 98% reduction for the face shields versus 97.3% for the masks (p = 0.01). Face shields offered an even better barrier effect than the mask against small inhaled particles (<0.3 µm–0.3 to 0.5 µm–0.5 to 1 µm) in all configurations. Therefore, it would be interesting to include face shields as used in our experimental study as part of strategies to reduce transmission within the community setting.

The aim of this study was to evaluate the comparative performance of masks and face shields in different experimental configurations. An experimental setup with two mannequin heads positioned at 1.70m high and at 25 cm each other was used. A fogger generated a particle’s airflow with a speed of 5m/sec from the emitter to the receiver head mannequin. Our aerosol generator produced 3 000 times more particles than a physiological cough situation. A particle counter allowed us to evaluate the number of particles received on a mannequin head located at a very short distance of 25 cm. The amount of all particles up to the selected particle sizes were counted with an optical particle counter on channels 0.3 µm, 0.5 µm, 1 µm, 2.5 µm, 5 µm and 10 µm. The reduction factors with a protection worn by the receiver alone, by the emitter alone and then the double protection of emitter and receiver were calculated. When the receiver alone wore a face shield, the amount of total particles was reduced (54.8%), while the reduction was less when the receiver alone wore a mask (21.8%) (p = 0.003). Wearing a protection by the emitter alone reduced much more the level of particles received by 96.8% for both mask and face shield. The double protection allowed for even better results, but close to the protection of the emitter alone: 98% reduction for the face shields and 97.3% for the masks (p=0.022). Even with small particle size emission (≤0.3µm), results were of the same order. Considering our results, protection of the emitter alone or double protection is much more effective than protection of the receiver only. Validated face shield should be included as part of strategies to safely and significantly reduce transmission in the community setting, in addition to masks or for people with disabilities or medical intolerance to masks.

: Numerous observational, epidemiologic data have suggested that the risk of COVID19 is related to shared meals or drinks. The presence of ACE2 receptors in the gastrointestinal tract supports this hypothesis. Furthermore, several patients experience gastrointestinal symptoms without any respiratory disease. The SARS-CoV-2 found on food and packaging in China and the epidemic resurgence attributed to foods are also strong indications of an oral transmission route. Unprecedented biopersistence on skin, food, and beverages supports this theory. Finally, animal models reproducing the disease by oral inoculation are additional arguments in favor of an oro-digestive route of infection.

Introduction : une équipe pakistanaise a réalisé un essai clinique multicentrique et randomisé en 2020, avec un traitement appelé HNS comportant du miel et la plante nigelle (Nigella sativa) sur des individus COVID-19. Matériel et méthodes : l’essai a été mené dans quatre établissements de soins médicaux au Pakistan. Le protocole multicentrique randomisé concerne 316 patients COVID-19 (210 présentant des signes cliniques modérés et 103 des signes sévères). Parmi les cas modérés, 107 ont bénéficié du traitement incluant Nigella sativa (80 mg/kg/jour) et Miel (1g/kg/jour) par voie orale jusqu’à 14 jours, tandis que 103 ont pris un placebo. Pour les cas graves, 50 patients ont reçu le HNS et 53 ont reçu le placebo. Résultats : il a été observé une réduction de la durée des symptômes à 6 jours (traités) contre 13 jours (placebo) pour les cas COVID-19 sévères, et de 4 jours (traités) contre 7 jours (placebo) pour les cas COVID-19 modérés. Le HNS a réduit le portage viral d’environ 4 jours pour les cas sévères ou modérés. Le traitement HNS a amélioré le score clinique au jour 6 avec une reprise d’activité normale dans 64 % contre 11 % parmi les cas modérés, et une sortie de l’hôpital dans 50 % des cas contre 3 % dans les cas graves. Pour les cas graves, le taux de mortalité a été réduit de 82 %. Aucun effet indésirable lié au HNS n’a été observé. Conclusion : le mélange HNS comportant du miel et de la nigelle semble très actif pour traiter des individus présentant une COVID-19 sévère ou modérée. Après confirmation de cette activité, le mélange HNS pourrait être potentiellement utilisé pour un traitement de tels malades.

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