The vice is tightening around the places and situations of contamination of Covid-19. In a recent study, the Pasteur Institute targets contamination in enclosed spaces and during meals. Interview with Dr. Jean-Michel Wendling, Occupational Health Specialist in Strasbourg.
For more than a year now, the coronavirus has been wreaking havoc on health without any clear understanding of its mode of propagation. The scientific community is confronted with a confusing virus: clusters develop here and not there, mostly indoors, but also outdoors, in food factories, it targets very different populations and, to top it all, it mutates rapidly and anarchically especially in mink.
A new study by the Institut Pasteur, involving 77,208 participants between October 1, 2020 and January 31, 2021, describes the main locations and circumstances of Sars-CoV-2 contamination. This “Comcor” study confirms that the transmission of the virus occurs more indoors (80% of cases) and during meals. “Meals play a central role in these contaminations, explain the authors, whether in the family environment (35% of cases excluding Christmas meals), friends (42%), or to a lesser degree professional (15%).
-Dr. Jean-Michel Wendling, here is a scientific study that will not surprise you since it confirms what you have been saying for a long time, including in the columns of IDJ and FrencDailyNews.
Yes, it does. Since May 2020, we are a group of experts who are convinced that mealtime is a risky moment simply because this friendly moment when we talk is favorable to the risk of contaminating the plate or the glass of his neighbor. We know that mealtime is a time when salivation is stimulated in an important way and that by talking, the risk of sending a spit is increased. The latter is projected over a distance of about 50 cm and easily falls into the environment of the guests in front of you.
-Under the title “Covid: the guilty meals“? last November, you and two other scientists were already questioning the transmission of the virus during meals. You were one of the first to alert public opinion. Have you been heard?
Aerosol transmission is a risk considered as possible but not the main one, even by the best experts in hospital hygiene of the AP-HP (opinion of December 9, 2020). This risk is invisible, anxiety-provoking, and people are so obsessed with the mask that they no longer think about hand hygiene.
However, in winter, the nose runs and blowing the nose is a very likely source of transfer of the virus to the hands, often in large quantities. 67% of French people say they do not disinfect their hands after blowing their nose and 6 out of 10 French people do not disinfect their hands before entering a food store. Almost no one disinfects their hands on public transport before touching the handrails. A third do not wash their hands before eating. Dirty hands, especially in winter, can contaminate the food handled and if we think of the bread cut for other family members or the beef or salmon tartar, the sushi prepared for the meal, there is reason to wonder about the intra-family risk, or even the cold food chain. Education on this aspect is therefore essential. Our observations also show that workplaces where employers take the measures we recommend, such as washing their hands before eating, sitting in staggered rows, at a distance from each other, or putting up dividing walls, pay off. This is the reason why the professional environment is probably less represented, but we are far from a generalization of these measures… In the professional environment, company restaurants have never stopped. However, the risk is rather controlled.
More recently, you co-organized an innovative “zero Covid” restaurant experience in Colmar that had a huge impact. When will the restaurants open?
More than an experiment, it’s a real-life situation that focuses on evaluating, testing and validating the practical feasibility with the restaurant owner. We conducted an upstream experiment with COMETE to see what the risk of air and surface contamination was by taking 4 sick military personnel who spoke for 1.5 hours above a table. The results were reassuring and allowed us to propose practical solutions.
The pre-testing with EasyCov also caught our attention with a test that could be performed at the end of the afternoon (for a meal organized in the evening: result in 40 minutes). This reflection around the meal risk allowed us to exchange and to build a series of proposals which are already partly implemented in professional environment. We also deal with the hypothesis of a surface contamination of the plate by a UVLED exposure after setting up and before bringing the plate to the table. These solutions may seem exaggerated for some or insufficient for others but we wish to move forward on the subject and experiment and validate in real life. The question we have to ask ourselves about the reopening of restaurants is not “when” but “how”?
You are a doctor specializing in occupational health, member of the Scientific and Citizen Council (CS4) of the city of Strasbourg. During a webinar, you plead for preventive measures in shops: hand hygiene, wearing a mask, distancing yourself. Why?
In May 2020, we were on a theory of main aerosol transmission. Today, we realize that non-food businesses are not high-risk places. Objects (books, clothes) are not put in the mouth and if hand washing at the entrance is well respected, if the mask is worn to avoid dispersing sprays when talking, the risk for the staff coming from the customers is close to zero.
On the other hand, as early as May 2020, we had raised awareness of the risk of transmission between employees during coffee breaks or meals. Hand hygiene around the kitchen or break room and distancing measures or dividing walls if one is face to face are essential. Caregivers have been heavily affected in the hospital setting and may not have been sufficiently aware of the risk in the break room or dining hall. The multi-national study conducted on caregivers published in September 2020 showed a three-fold higher risk of contamination through contact with co-workers and a ten-fold higher risk in the restaurant outside of work compared to the risk of working in contact with COVID patients!
-What about meals at home? What preventive measures can be taken?
Simple precautions must be taken to avoid thousands of intra-family contaminations: when returning from shopping, washing fruits and vegetables from the market is associated with a 94% risk reduction! Wash your hands, for the person preparing the meal, wear a mask by the cook. Hand washing for the whole family before going to the table is essential as is hand washing after the toilet, obviously, which is not applied by 23% of French people (IFOP survey October 2020). Finally, if someone is symptomatic, perform a rapid test such as Easycov with results within an hour: if positive, the patient will be isolated with a mask, hand washing and especially isolation for his meal for a few days. This will protect the whole family.
These measures have already proven to be effective in families with only one patient without any spread. It is enough to apply these measures well to reduce the risk to the maximum.
Dr. Jean-Michel Wendling, specialist in occupational health prevention in Strasbourg, is a scientific consultant for infodujour.fr and Frenchdailynews.com