COVID-19: Prevention

To prevent infection with SARS-CoV-2 (novel coronavirus: 2019-nCoV) or COVID-19 (corona virus disease 2019), attention must be paid to reducing individual risk factors. Behavioral risk factors

  • Avoid contact with ill persons during the phase of infection.

Note the routes of transmission of the pathogen (route of infection):

  • By droplet infection, i.e. primarily via secretions of the respiratory tract (respiratory system): the infection can enter through mucous membranes of the respiratory tract or indirectly through hands, which are then brought into contact with oral or nasal mucosa, as well as the conjunctiva of the eyes.
    • Possibly also by aerosolization of the virus during normal breathing; however, to date, it is thought that pathogens spread via the respiratory air are probably not at high enough doses to lead to infection (animal studies with ferrets). At choir rehearsals or in restaurants, there are situations in which SARS-CoV-2 has been transmitted via aerosols.
    • The U.S. Centers for Disease Control and Prevention (CDC) indicates that SARS-CoV-2 can also be transmitted via aerosols, even over a distance longer than six feet (about 1.8 meters) in enclosed spaces “with only poor ventilation.”
  • Possibly also fecal-oral/smear infection is conceivable Note: SARS-CoV-2 is detectable in stool samples longer than in respiratory secretions.
  • Vertical infection, i.e., through infected mothers:
    • Transplacental transmission, i.e., transmission via the placenta (placenta), of SARS-CoV-2 from a pregnant woman affected by COVID-19 during late pregnancy to her offspring.
    • 30 hours postpartum (after birth).
    • Through breast milk? (SARS-CoV-2 RNA was detected in the breast milk of one of the women for four consecutive days): one infant was infected (mother wore a mouth–nose protection when handling the infant, hands and breasts were disinfected, and breast pump and other breastfeeding utensils were regularly disinfected).Note: Pasteurization of breast milk using the Holder method (heated to 62.5°C for 30 minutes) reliably inactivates SARS-CoV-2.

    In a small observational study (9 women), no vertical transmission (transmission) of the pathogen was detected in women who became ill in the 3rd trimester (third trimester of pregnancy).

Infectivity

  • In liquid or dried material, coronavirus SARS-CoV-2 remains infectious for 9 days, for example, on doorknobs, doorbells, etc.
  • On stainless steel and plastics: 3 days.
  • In aerosols in the air: 3 hours
  • On smooth surfaces such as those of cell phone displays and ATMs, SARS-CoV-2 coronavirus can survive for up to 28 days at 20 °C.

Prevention factors (protective factors)

  • Vitamin D: Vitamin D deficiency is associated with a critical course in COVID-19.
  • Normal weight (ie, weight reduction in the presence of obesity):
    • Obesity (BMI (body mass index) > 40)-patients < 60 years of age with obesity were twice as likely to require hospitalization for COVID-19 as those of normal weight; BMI > 35: 7-fold increased risk; obese patients COVID-19 patients were particularly likely to require ICU care
  • Cytokine inhibitors (cytokine-blocking drugs): tumor necrosis factor alpha (TNFα), interleukin-6, and interleukin-1; according to one study, cytokine inhibitors are thought to limit SARS COV-2 virus infection from the beginning so that antibodies are not produced.
  • Androgen deprivation therapy (ADT) for prostate carcinoma (prostate cancer) appears to be partially protective against SARS-CoV-2 infection. Transcription of TMPRSS2 – a transmembrane serine proteinase – regulated by the androgen receptor plays a role. GnRH agonists or antagonists or androgen receptor blockers drive down the expression of TMPRSS2.

Preventive measures

Notice: In China, 70% of SARS-CoV-2 infections occurred within the household.Disinfecting the home daily reduced the risk of infection by 77% and wearing nasal-mouth protection (MNS) by 79%. The following prevention measures are effective:

  • Isolation and quarantine measures are essential!
    • Social distancing:
      • Mind.1.5 meters (1.0 meters is associated with a risk of infection of 3% / with each additional meter distance (up to 3 m), the risk is halved again; a smaller distance with a risk of about 13%).
      • Of coughing or sneezing people (at least 2-3 m distance).
      • Walkers: 4-5 meters, joggers and slow cyclists: at least 10 meters, fast cyclists: -20 meters and avoid the slipstream of like-minded people.
    • Assembly bans and school closures
    • Avoid handshakes and hugs of greeting.
  • Turn away when coughing and sneezing, if possible sneeze into the crook of the elbow (= cough etiquette).
    • Use disposable handkerchiefs
  • As little as possible touch mouth, nose or eyes with your own hands.
  • For most epidemiologists, hand hygiene has the greatest importance in the containment of pandemics and epidemics.
  • Hand washing including forearms (also applies to the face if you have been with people indoors).
    • Moisten hands under running (warm) water.
    • Thoroughly soap all parts of the hand incl. interspaces and forearms (20-30 sec.). After spreading the soap, interlock fingers and rub back and forth; do the same with palm to back of hand, also interlocking fingers (disinfectant additives are usually not necessary).
    • Thoroughly wash off the soap scum.
    • Thoroughly dry all parts of the hand including interstices and forearms (change towel daily in the process).
    • If necessary, then use hand disinfection (see below).
      • Always after:
        • Direct contact with other people
        • Coming home
        • Coughing and sneezing
        • Blowing the nose
        • Going to the toilet
        • Contact with sick people
        • Contact with animals
      • Always before:
        • Food preparation
        • The food
  • Hand disinfection: in addition to frequent washing of hands with soap and water or cleaning hands with alcoholic solutions, disinfectants should be used:Apply agents with proven efficacy, with the range of action “limited virucidal” (effective against enveloped viruses), “limited virucidal PLUS” or “virucidal”.
    • Disinfectants based on 62-71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite (NaClO) can effectively inactivate the pathogen within one minute.
    • Alcohol–water mixtures based on 70% v/v 2-propanol or 80% v/v ethanol are sufficiently effective against bacteria and coronaviruses at an exposure time of 30 seconds and a volume of 3 ml.
  • Surface disinfection: before disinfection should always be previously cleaned surfaces. Cleaning should progress from the least to the most contaminated areas and from top to bottom.Disinfectants: ethanol (concentration 70 to 90%) with chlorine-based products such as hypochlorite (concentration of 0.1%) for general disinfection. For large areas contaminated with blood and body fluids, hypochlorite at a concentration of 0.5% is recommended.
  • Nasal-mouth protection (MNS): risk of infection: about 3%, compared to 13% without a mask.
    • All members of the household of SARS-CoV-2 infected persons and the ill personNote: Neither cotton masks nor surgical masks can safely stop SARS-CoV-2 from coughing COVID-19 patients.
    • People who have had contact with infected people and do not know if they may have contracted it
    • Medical personnel who care for the sick (for this, see “Further therapy/general measures).

    Announcement of the Robert Koch Institute on MNS (April 2020): the precautionary wearing of a mask when shopping and on public transport helps to minimize the risk of transmission of the virus to others. This is true even for people who are asymptomatic.More on MNS:

    • Face masks can provide a significant reduction in the output of influenza and corona viruses.
    • A group of researchers from England and Hong Kong also recommends considering broad mask recommendations, provided there are enough masks.
    • Mouth-to-nose protection can not only protect against infection with SARS-CoV-2.It also prevents carriers from ingesting the viruses in larger quantities, which could prevent severe disease in the event of infection. The mouth-nose covering limits the amount of viruses ingested (variolation) through a filtering effect and leads to less severe and more often asymptomatic courses.
    • Recommendations for making textile face masks.
    • Reprocessing: e.g. 70 °C dry heat for 60 minutes.

    Note: Only so-called FFP2 and FFP3 respirators can prevent infection by droplet transmission.The Robert Koch Institute has issued regulations for the reuse of mouth-nose protection and FFP masks: see here.

  • Eye protection (glasses, goggles, visor): without the protection about 16% risk of infection – with these measures about 6%.
  • Clothing regularly wash and ventilate.
  • Window ventilation in terms of shock ventilation (brief air exchange: about 3-10 minutes) to lower the risk of infection depending on:
    • Room type: office room after 60 minutes; meeting room after 20 minutes.
    • Minimum duration of shock ventilation: summer up to 10 minutes (taking into account the outside temperature); spring/fall: 5 minutes; winter 3 minutes.
  • Control of room air: a relative humidity of 40 to 60% can reduce the spread of viruses and absorption through the nasal mucosa. The reason is that with higher humidity, droplets grow faster and fall to the ground earlier, so they are less inhaled by healthy.
  • Vaccinations for people 65+ and immunodeficiency (immune deficiency): catch up pneumococcal vaccination if not already done!
  • Measures to strengthen the immune system (see below “immunodeficiency – immune deficiency – susceptibility to infection / further therapy“): see also “Further therapy / nutritional medicine“.