The current dynamic situation surrounding the new SARS-CoV-2 and COVID-19 pandemic raises questions. Especially for health care workers, it is essential to have up-to-date information on protective and hygienic measures in order to minimize the risk of infection in the already very challenging clinical work during the current corona crisis. Prof. Dr. med. Philip Tarr, specialist in infectiology at the Cantonal Hospital Baselland, answered questions from the audience in a video conference call.
The infectiologist pointed out that the answers to the questions were based on the current state of knowledge and that there were still many uncertainties because the data were scarce and the virus was new. “We extrapolate very strongly from SARS, MERS, influenza, etc.”. The expert also refers to the continuously updated regulations of the FOPH, which are an important basis and are also applied in the Baselland Cantonal Hospital. The following is a compact summary of the interactive web-based expert talk as part of a special edition of WebUp on 26.03.2020.
The most important questions and answers about dealing with the coronavirus
What are the most important hygiene measures?
Disinfecting hands is a very important hygiene measure and care should be taken not to touch your face if possible.
What should be disinfected in the family practice?
It is perfectly reasonable to disinfect the following surfaces in treatment rooms after patient contact: Table, chair, examination couch, door clinics, light switch. Large-scale environmental disinfection, Ebola/astronaut suits, head hoods, however, are rather not that useful. The dangerous exposures, he said, are when the viruses are inhaled or when viruses get from the hands to the face. “The few viruses it has in the environment are not very important,” the infectiologist said. Prof. Tarr also does not consider constant floor disinfection in the practice to be necessary; the virus dies within a few hours.
Can you get infected by viruses present on surfaces (e.g. on newspapers, packaging, money, etc.)?
While it is known that coronaviruses survive for several hours on surfaces, it is only a small number of viruses. In his opinion, this does not pose a risk of infection, but only through contact with secretions, whereby one inhales several million viruses (e.g. if one has close contact with an infected person without a mask).
What rules should you follow regarding social distancing?
Care should be taken to ensure that the distance is at least 180 cm. This also applies to the waiting room, meeting room, reception (possibly install plexiglass screen). Keep patients with suspected symptoms away from practices (send them to clarification centers). Don’t hold unnecessary meetings, switch to video conferencing instead. Remain in the home office whenever possible. Schools closed, restaurants closed, quarantine if necessary. From literature we know that combined interventions are significantly more effective than single measures.
As a primary care physician, do you have the ability to triage patients with suspected symptoms?
In the canton of Baselland, general practitioners can send patients with suspected symptoms directly to clarification centers.
What is known about the effectiveness of mask protection in clinical practice?
A surgical mask, he said, is sufficient in clinical practice and should be worn for all patient contacts (even though nothing about cold symptoms was mentioned at registration). Hands must be disinfected before putting on the mask. Wearing an FFP2 mask is only required for aerosol-generating tasks. It is not necessary to wear FFP2 mask and over aprons at all times. Surgical masks are known to be similarly effective against influenza, H1N1, and SARS in clinical settings, he said. FFP2 (plus face protection, overskirts) are only useful for aerosol-generating tasks. “There is still too little data for the new coronavirus, but we assume that a surgical mask is about as effective as FFP2,” adds Prof. Tarr.
What is the current regulation regarding contacts of confirmed cases?
One should systematically search for such persons and send them into self-quarantine for 10 days (criteria for “risk contacts”= indoor, at least 15 minutes, less than 180 cm, without mask). Exception: health workers may/should work applying the protective and hygienic measures, otherwise the health system collapses. Minimize aerosol-generating devices: early intubation rather than noninvasive ventilation. At present, moist inhalation is no longer performed at the Baselland Cantonal Hospital, e.g. for patients with asthma or COPD. Instead, Impramol is administered via metered-dose aerosol and preswitch chamber in consultation with the pulmonologists.
What are criteria for conducting a test?
According to Prof. Tarr, only symptomatic individuals should be tested; testing asymptomatic individuals is not useful in the current situation. This also applies to health care workers, he said. For one thing, a negative test result has poor predictive value, and for another, tests are currently a scarce commodity. “In practice, it is currently not feasible to test asymptomatic individuals every 48 hours,” the expert explains. For tests in symptomatic pesons, a negative test result is considered valid at the Baselland Cantonal Hospital if the symptom duration beforehand was at least 72 hours. This is important to be sure not to miss any viruses, explains Prof. Tarr.
How reliable are test results when performed correctly?
He recommends taking nasopharyngeal swabs, saying that they are more sensitive than throat swabs; moreover, the latter often cause nausea. Regarding technical performance of nasopharyngeal swabs, he said it is important to stay at least 15 seconds to the posterior wall of the nasopharynx, all the way back, and rotate swabs slightly. With regard to sensitivity, there are hardly any data yet; it is simply assumed that true-positive results are accurate.
How long does a swab remain positive in an infected person?
On average, a smear remains positive for about 20-22 days, in extreme cases up to 37 days. But in mild courses, the number of viruses in the swabs decreases significantly within a week of symptom onset, presumably reducing contagiousness. Exceptions are persons with a severe course, who come to the intensive care unit with respiratory distress, pneumonia, etc.. In these cases, the number of viruses can increase further during the course of the disease. But what is known from influenza, for example, is that when someone is clinically better, the number of viruses in the nasopharynx also decreases.
Does the coronavirus really pose a life-threatening risk only to the elderly and chronically ill?
Criteria under which conditions one belongs to a risk group are specified on the one hand by the FOPH and on the other hand there are also assessments of this by various professional societies. This information is reliable and is considered a general rule. But sometimes you have to look at it on a case-by-case basis, he said. He said there are rare cases of young sufferers without preexisting conditions who need to be cared for in the intensive care unit. In these, the chances of survival tend to be better, but even in these cases, a relatively long duration of ventilation is required.
Why is herd protection not an appropriate strategy regarding coronavirus?
On the one hand, the risk of serious symptoms in infected persons from risk groups is too high, and on the other hand, the capacity of the health care system is limited.
What are criteria for de-isolation after coronavirus disease?
In the Cantonal Hospital Baselland, the current criteria of the FOPH are used for de-isolation: onset of symptoms at least 10 days ago and affected person has been asymptomatic for at least 48 hours. Negative smear is not a criterion for de-isolation, which also has to do with the fact that there are a limited number of tests available.
What are criteria for de-isolation after close contact with coronavirus infected person?
For persons in quarantine due to close contact with infected person (criteria for close contact: at least 15 minutes, less than 2 m, without mask), the Cantonal Hospital Baselland consults with infectious diseases specialists. Currently, the duration of a quarantine is 10 days according to the directive of the FOPH. Prof. recommends following the recommendations of the FOPH. In individual cases, the incubation period can be up to 14 days. “If individuals leave quarantine after 10 days, they should still be cautious,” adds Prof. Tarr. This means that affected persons should then still consider hygiene and other precautionary measures.
What measures are necessary for health care workers who have had coronavirus before returning to work?
At the Baselland Cantonal Hospital, the regulations of the FOPH apply. It is very important that the person concerned observes the hygiene and precautionary measures after returning to work, for example, wearing a mask and regularly disinfecting their hands.
How long does immunity last after surviving coronavirus disease and when will antibody testing be available?
It is currently assumed that one is immune for at least a few months after surviving COVID19. He said there is hardly any empirical data on this yet, so you also don’t know whether you will still be protected in the next winter season, for example, or not. It is possible that the new coronavirus will be endemic, that is, it will not simply disappear, as is the case with certain other viruses. Antibody tests will be available very soon; at the Cantonal Hospital Baselland, it is currently assumed that this will be the case as early as next week or the week after (information status: 26.3.2020). Antibody tests are suitable for identifying people who are immune to the coronavirus, the expert said.
When is it appropriate to use antipyretic medication?
Prof. Tarr advises against using them routinely. Antipyretic drugs are useful when the general condition or subjective state deteriorates or the fever rises sharply within a short time. Paracetamol can be used as the first-choice drug, and metamizole (e.g. Novalgin®) as the second choice. According to current findings, ibuprofen should not be used, although the data available in this regard are rather limited. Regarding the use of steroids to treat pneumonia in the context of coronavirus, Prof. Tarr cautions that it is currently not known exactly how the use of immunosuppressants affects the course of the virus. This also applies to other immunosuppressive substances, he said, adding that weighing the benefits and risks is a very complex issue.
Are there binding criteria regarding resuscitation?
At the Baselland Cantonal Hospital, the guidelines of the Swiss Academy of Sciences are applied.
What is known about long-term effects of mechanical ventilation?
Little is known about this at the moment, he said, and the focus is currently on offering life-saving measures to hospitalized patients and being happy if they survive. “Right now, we’re in crisis mode and we have to see that we can manage the case load,” the infectiologist said.
Is there an explanation for different infection and mortality rates of different countries/regions?
He said not much was known about it at the current time. The higher mortality rates in Italy compared to Germany or Switzerland are probably related to overburdened health care facilities. The fact that the incidence figures (number of new cases per 100,000 inhabitants) are higher in Switzerland than in other regions of the world has something to do with the border regions, which traditionally play an important role in the Swiss economy.
Source: Forum for Continuing Medical Education (FOMF): WebUp: Expertentreff Infektiologie – Talk zum Thema COVID-19. Prof. Dr. med. Philip Tarr, Kantonsspital Baselland, 26.03.2020.
