1. Other potential sources of infection
Air conditioning
Since aerosols play a role in the transmission of COVID 19 in addition to virus-containing droplets, it is conceivable that the spread is promoted by ventilation and air conditioning systems. Therefore, in central ventilation and air conditioning systems, regular servicing and control are very important, for example, to avoid false flows of the extracted air. The airflow must be consistently separated from each other so that the air extracted in one room cannot reach other areas of a building.
Besides, the use of high-performance separation filters (HEPA filters as in hospitals or laboratories) is important, which can hold back both coronaviruses and released droplets. It is also recommended to regularly replace the room air with fresh air via opening windows, as this can further reduce aerosols.
Is it possible to become infected with coronaviruses via food or objects?
There is currently no evidence of food infections, and similarly, infection via objects seems unlikely (no reliable evidence). However, transmissions due to smear infections over surfaces that have recently been contaminated with viruses are conceivable and cannot be ruled out. How quickly COVID-19 viruses are inactivated on different surfaces is not yet sufficiently investigated.
Therefore, when in contact with surfaces that may have come into contact with other people outside the close family environment, one should wash one's hands well and, if necessary, disinfect them at certain workplaces (see also public transport, professional environment above).
Can COVID-19be transferred to canteens and other community catering facilities via crockery and cutlery?
As shown above, an infection via smear infection by such contaminated objects is conceivable if it has previously been coughed up or sneezed, or if someone has touched these objects with viruses on his hands, then they enter the mouth with food. Whether the viral load is then sufficient to infect others is not sufficiently investigated.
In principle, strict hygiene rules should always be observed in catering establishments, as numerous infections (including bacterial infections) can occur. If hygiene strictly adheres to a COVID-19 infection via food or objects in the canteens is rather unlikely.
Is the virus inactivated by washing by hand or in the dishwasher?
Coronaviruses are sensitive to fat-releasing substances such as alcohols and surfactants, which are contained in soaps and dishwashing detergents. These viruses are also inactivated in the dishwasher at 60°C or higher temperatures during washing and drying.
Washing with soap must be done thoroughly and long enough. This is true in dishwashers. In the sink, the cutlery and dishes should be soaked in warm soapy water (45°C) for a while and then rinsed well.
More detergent should be used for colder water. The subsequent drying also contributes to the inactivation. There is not yet sufficient investigation data on these measures, but the inactivation is plausible.
For the related SARS coronavirus, a laboratory study showed that treatment with a commercially available detergent for 5 minutes at room temperature led to complete virus activation. (https://academic.oup.com/cid/article/41/7/e67/310340).
Can coronaviruses be transmitted by touching surfaces such as cash, card terminals, doorknobs, smartphones, handles of shopping carts, packaging, or bags?
Can coronaviruses be transmitted via baked goods or fresh fruit and vegetables and similar foods?
Coronaviruses can get onto baked goods, fruits, or vegetables by directly sneezing or coughing from an infected person. However, they cannot reproduce in or on food; they need a living animal or human host. A smear infection of another person appears possible only if the virus is transmitted via the hands or the food itself to the mucous membranes of the nose of the eyes or the mouth and throat shortly after contamination. Again, the recommendations on the general rules of hygiene of everyday life apply, such as regular hand washing and keeping hands out of the face.
In the case of baked goods as well as fruit and vegetables in shops, the general hygiene rules must also be strictly observed, irrespective of the COVID-19 problem; various infections can generally occur if this is not observed.
Sellers should always wear a mouth-nose cover and change disposable gloves from customer to customer (especially because of cash – better is the use of payment cards, which only the customer touches). Thorough washing of foods such as fruits and vegetables and frequent hand washing during processing should be strictly observed.
Can coronaviruses be transmitted via milk from cows fed with potentially contaminated food?
A transfer of COVID-19 via milk, as for other foods, is unlikely, according to the current state of knowledge. The Federal Institute for Risk Assessment is not yet aware of any COVID-19 infections via this transmission path. The Friedrich-Loeffler-Institute and the Robert Koch-Institute are not yet aware of any information from China or other countries affected by COVID-19, which suggests a special role of feed for home and farm animals. There is no evidence to date that feeds is a vehicle for coronaviruses.
Can coronaviruses be transmitted via meat and meat products?
Contamination of meat or meat products with coronaviruses could theoretically take place during slaughter or meat cutting and processing. However, the Federal Institute for Risk Assessment is not yet aware of any COVID-19 infections related to the consumption of meat products or contact with contaminated meat products. Farm animals used for meat production are not, according to current knowledge, infected with COVID-19 and therefore cannot transmit the virus to humans via this route.
Coronaviruses can be transmitted from an infected person to sausage and meat. Here too, the hygiene rules already mentioned apply strictly. Infection chains in slaughterhouses are not likely through meat contamination, but from person to person, especially through the respiratory tract. However, smear infections via previously contaminated meat are also conceivable here.
To protect yourself from virus transmission, it is always important to observe the general rules of hygiene of everyday life such as regular hand washing and keeping hands away from the face even when preparing food. Furthermore, meat should generally be sufficiently and evenly heated before consumption, also for protection against possible other pathogens, until leaking meat juice is clear and the meat has adopted a whitish (poultry), grey-pink (pig) or grey-brown color (beef). Further information on hygiene in the handling of food was provided in previous teaching letters.
People's usual questions about COVID-19 can be answered from chapters 1-14 above. The answers to the following questions or topics are also derived from the points discussed above.
Da few things are emphasized again, follow concise answers to common questions.
Other common questions
What the people are worried about:
2. Back to work
Where work assignments are possible under the protective measures and rules of conduct, the state governments and health authorities determine. It is important to comply with the recommended rules of conduct.
4. Second Corona wave
This is possible.
5. What is the risk for children in schools?
Children appear to be less likely to be affected by a manifestation of COVID-19 infection. When they are affected, they are mild or asymptomatic often. Precisely because they usually have closer contact with other children, they can spread the virus many times if they are infected.
Even with the changes in school (smaller classes, hygiene, and distance rules – new forms of instruction with more shares of homeschooling, etc.), it will hardly be possible to avoid the closer contacts of children in kindergarten, daycare, and school.
The precautions for reducing the number of transmissions by children and adolescents will still have to be adapted to the experiences to be made, which can vary greatly from region to region.
Only if the rules of conduct are consistently adhered to – the same applies to children and adolescents –the high number of infections will be avoided as long as it has not yet been achieved vaccination or even higher "contamination" with herd immunization.
5. What happens if I need medical care now? Is it safe to go to the hospital?
If medical treatments are necessary, these should be perceived. It is also important to pay attention to the rules of conduct. If doctors or hospitals do not take sufficient precautions, contact the health department. Appropriate facilities will then be obliged to take sufficient measures or will be closed. Only treatments with a doctor or in the hospital, which can be postponed for a long time without any problems (let the doctors decide), you should postpone at this time.
6. What about vacations on the seaside? Going to Hotels?
Health recommendations for trips abroad are given by the authorities. The German authority has issued a travel warning for unnecessary tourist travel to countries outside the EU/ Schengen areas. The Robert Koch Institute does not make any recommendations and does not offer travel medical advice.
In general, it must be said that traveling in regions with higher infection rates has higher risks, even if the hygienic measures and rules of conduct are introduced in the hotels as recommended.
However, as long as there is no herd immunity, an infection can also take place in the own country with lower case numbers if one or more infected persons and especially superspreaders occur in your vicinity.
All hygienic measures and rules of conduct cannot prevent the spread completely, since only the immunization (vaccination or sufficiently high penetration) can prevent the spread.
It is a risk assessment that always depends on the current developments in a region as well as on the own consistent implementation of the rules of conduct.
Read the points on possible routes of infection.
This shows that at present, in theory, an infection can always occur anywhere – with different frequencies (you habitually reflexively grasp yourself in the face - on the mouth and eyes or the nasal mucous membranes).
If no infectious person is in close contact, negligent behavior (disregard of the rules of conduct) can have no consequences, but often one does not know if there are infectious persons in your environment, as even the superspreaders can be without symptoms. As a rule, infectivity exists 1-3 days before the first symptoms of the disease and there are on average 43% asymptomatic histories in infected people. Besides, COVID-19 transmission to other people via smear infections (e.g. coughed on objects) cannot be excluded.
It does not matter if it's the holiday at the lake or in the mountains. Crucial is the presence of infectious people with whom one can come into closer contact and whose aerosols are contaminated.
When staying outdoors, the risk of infection is often lower (especially in nature, where you are not in crowds and where there is more wind). Staying in the hotel and restaurant, on the other hand, can also be the place of contagion in such holiday areas – always provided that there is an infectious person there.
7. What are the risks of eating in restaurants?
The same statements apply here as on the previous points. It is safer to dine outdoors in the restaurant in good ventilation conditions. The tables must have a distance between it of 2m and in the corridors as well as the toilets, people must not meet without the minimum distance. Staff must consistently comply with all rules of conduct. Otherwise, it is safer to get the food home from the restaurant.
Infections are more likely to occur in restaurants if you stay there longer indoor and have a lively conversation. If there is a higher number of customers or guests, the risk of infection increases anyway, but in the restaurant, it is often riskier because you usually stay there longer than, for example, in a shop.
The local conditions should, therefore, be taken into account – e.g. whether the protective measures are well implemented, and care should be taken to ensure that there are not too many guests there, as well as the ventilation is very good. If air conditioning is available, the protection criteria for such a system must be guaranteed.
8. What are the risks in Shopping Malls?
Here the same points apply. In several places, disinfectants should always be provided for the hands in and in front of the shops – via an automatic application (spraying) so that the disinfectant bottles do not have to be touched. The possible relaxation of certain measures always depends on the current infection data in the area. The distance rules should always be supported in the individual stores with markings on the floor and corresponding barriers. Stores that do not do so pose a higher risk if there are infected people on site.
9. If I am a business owner, how do I secure the health of my customer
The same statements apply here.
10. How do I detect old and lonely people?
That is the job of health boards, but everyone should keep a good look at their surroundings and neighbor-hood and ask other people (especially elderly) if they need help, or what they can bring from shopping and put in front of the door. There are local aid organizations or self-help groups that should be contacted.
11. Is it safe to meet your family and have family events?
The rules of conduct also apply to family celebrations when family members meet who do not meet daily in the close house community. Only in the closer house community and with fewer cases of infection in the region, gatherings of e.g. 2-3 families are rather safer. In general, however, it can be said that one should pay particular attention to the older (70+) with the rules of conduct – especially if there are existing pre-diseases.
Otherwise, larger family reunions are likely to be possible if there are no risk groups among them and there are only small numbers of cases in the region anyway. No one can take the risk assessment away from you. You need to familiarize yourself with the items 1-15 covered to be able to assess some things yourself better. Family reunions should be more advantageous in terms of tracking infected people and disrupting chains of infection.
12. Having a Drink
Can coronaviruses cause respiratory infections by transmission via drinking vessels in restaurants or in community catering facilities, such as canteens?
According to the World Health Organization (WHO), there is so far no evidence that the coronavirus COVID-19 is transmitted by water (a drink). In the current outbreak with COVID-19, the oral-alimentary transmission pathway (via the esophagus and stomach) does not play a role according to the current state of knowledge. Virus contamination of drinking vessels is conceivable if such a vessel has not been sufficiently cleaned in the meantime.
What if I am dating a new partner? How do I know they are not sick?
At this stage, you cannot be sure whether the infection is possible with new partners because even asymptomatic individuals can be infectious. Of course, these are probabilities and therefore the risk is always dependent on local case numbers. Also, the different routes of infection play a role (where and under what circumstances one meets the person). The recommended rules of conduct are always important as long as there is no vaccination and herd immunization.
13. What is when I meet someone who recovered from Corona? Is he a risk?
Currently, experts believe that recovering patients have a low risk of developing COVID-19 a second time. Initial studies have shown that individuals develop specific antibodies after undergoing SARS-CoV-2 infection that can neutralize the virus in laboratory tests.
However, it is still unclear how robust and permanent this immune status is being built up and whether there may be differences from person to person. Experience with other coronavirus diseases such as SARS and MERS suggests that at least partial immune status could last up to 3 years.
Prof. Dr. Werner Seebauer is Dean of Studies – Association of German Preventologists, Head of Preventive Medicine Department of Institute of Transcultural Health Sciences (European University Viadrina) and Head of Preventive Medicine – NESA (The New European Surgical Academy). Since 2000, prof. dr. Werner Seebauer worked only in preventive medicine, after ten years spent at the Frankfurt University Hospital. He is also involved in the medical professionals training for nutrition and prevention.
