RATIONALE FOR THE CLASSIFICATION OF THE SARS-COV-2 VIRUS - BAUA
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Committee on Biological Agents (ABAS) – Decision 1/2020 update of 1 October 2020 Page 1
Classification of SARS-CoV-2 as a risk group 3 biological agent
Committee on Biological Agents (ABAS)
Decision 1/2020 of 19 February 2020 (update of 1.10.2020)
Rationale for the classification of the SARS-CoV-2 virus
as a risk group 3 biological agent
Background
Cases of a new type of respiratory disease were reported for the first time in the Chinese city of
Wuhan (Hubei Province, People's Republic of China) in December 2019. All patients were
reported of having previous contact to a food market in Wuhan where fish, marine and other wild
animals were marketed. During the course of infection, some patients developed severe
pneumonia. On 11 February 2020, the disease was officially designated “Coronavirus Disease
2019” (COVID-2019) by the WHO. Based on available data, it was estimated that approximately
2 % of infected people died. By sequencing the virus genome upon isolation from patients, the
pathogen has been identified as a new member of the Coronaviridae family and has been
assigned to the subgenus Sarbecovirus (subfamily Orthocoronavirinae, genus Betacoronavirus)
by the International Committee on Taxonomy of Viruses (ICTV). The sequence data showed more
than 85 percent sequence identity to SARS-like coronaviruses previously detected in bats (Bat-
SL-CoVZC45, Bat-SL-CoVZXC21). Based on this information, the novel human coronavirus was
classified as type 2 of SARS-CoV (Severe acute respiratory syndrome-related coronavirus,
SARS-CoV-2).
SARS-CoV-2 was recognized as the causative agent of a systemic infection often manifested as
severe pneumonia. In addition, it was shown that SARS-CoV-2 infection could be associated with
endothelial dysfunction, deep venous thrombosis and microinfarctions in blood vessels of the renal
and coronary system. High amounts of SARS-CoV-2 have been detected in the respiratory system
of infected patients. Particularly in non-ventilated rooms and building areas, rapid human-to-human
transmission has been observed to occur by droplets and aerosols. Furthermore, SARS-CoV-2 can
be transmitted before onset of Covid-19 symptoms (fever, cough, and pneumonia) and as well as
by individuals with asymptomatic infection. Some SARS-CoV-2 infected individuals develop only
mild symptoms of a common cold, which are not recognized as COVID-19 by the affected
individuals or third persons. Thereby, efficient spreading of the infection occurred and resulted in
the current pandemic. On 1 October 2020, more than 33 million of infected people have been
diagnosed and registered worldwide. Among the infected individuals, 1.014.352 have died resulting
in a case fatality rate of 2.98 % (Johns-Hopkins-University). In Europe (EU including UK) more than
3 million infections have been registered, 190.272 infected people have died (average case fatality
rate: 5.7 %). Case fatality rate may vary from 1.7 % (Austria), 2.3 % (Denmark) and 3.3% (Germany)
to 5.3 % (The Netherlands), 11.4 % (Italy) and 9.3 % (United Kingdom). Further details and data is
provided by Johns-Hopkins-University, USA [15], and the ECDC, Sweden [17]. Since July 2020,
the case fatality rate decreased notably as compared to the situation in spring. At present, about
1 % of infected people in Germany die from COVI-D19 [13, RKI, daily situation report of
28.9.2020]. Several reasons are discussed for the declining lethality:
(I) Currently, younger people become infected, mostly not developing severe COVID-19.
Committee on Biological Agents (Ausschuss für Biologische Arbeitsstoffe, ABAS) – www.baua.de/abasCommittee on Biological Agents (ABAS) – Decision 1/2020 update of 1 October 2020 Page 2
Classification of SARS-CoV-2 as a risk group 3 biological agent
(II) Due to changes in the regimen of routine diagnostic testing from ill to healthy individuals (e.g.
travelers, teachers, nurses, clinicians), mild or asymptomatic infections become detected
more frequently.
(III) Clinicians and practitioners are gaining more experience to treat COVID-19 patients.
Remdesivir is available for antiviral chemotherapy of severely ill patients.
Rationale for a classification in risk group 3
SARS-CoV-2 is similar to SARS-CoV-1, a member of the subgenus Sarbecovirus, which is
pathogenic to humans and has triggered the 2002/3 SARS epidemic (mortality rate 9.6 %). Albeit
to a lesser extent, similarities of SARS-CoV-2 to MERS-CoV were observed. MERS-CoV is the
causative agent of the Middle East respiratory syndrome, a severe lung disease (mortality rate
34 %) reported from citizens of the Arabian Peninsula states. SARS-CoV-1 and MERS-CoV are
both classified as risk group 3 agents. At present, no antiviral therapy and preventive vaccines
are available for SARS-CoV-2. Therefore, also SARS-CoV-2 is assigned to risk group 3. This
assignment is further supported by epidemiological data indicating a high potential for human-to-
human transmission.
Classification of SARS-CoV-2 in risk group 4 is not justified according to definition and criteria laid
down in the national guideline TRBA 450 “Criteria for the classification of biological agents”. In this
context, it is mandatory to consider the severity of the disease caused by the respective biological
agents. Assignment to risk group 4 is reserved to biological agents causing severe disease in almost
all infected individuals independent of age and gender. In general, infections by risk group 4 viruses
are associated with high fatality rates of 30 % and higher. These criteria are met with all virus species
causing hemorrhagic fever (e.g. ebola virus, south-american hemorrhagic fever virus, [21]). With
SARS-CoV-2, the situation is different:
(I) Only distinct groups of SARS-CoV-2 infected individuals are reported to develop severe
courses of the disease. Data provided by the Robert Koch-Institute demonstrate that the
majority of fatal cases (86 %) is observed with infected patients above 70 years of age. Mean
age of deceased patients is 82 years [16]. The situation is similar in Bavaria, the federal state
most severely affected by the SARS-CoV-2 infection: here, 85% of the deceased were at an
age of more than 70 years, although their proportion is only 14 % among all registered
COVID-19 cases in Bavaria [14].
(II) As expected for patients of advanced age, almost all deceased COVID-19-patients suffered
from co-morbidities, i. e. obesity, coronary heart disease, asthma, copd, diabetes mellitus
type 2, peripheral artery disease and neurodegenerative disorders [16].
(III) Furthermore, first data demonstrate that a significant number of SARS-CoV-2 infected
individuals do not develop symptoms or that symptoms are transient, mild and similar to
diseases known as “common cold” (cough, sneezing etc.). Based on the detection of SARS-
CoV-2 specific antibodies, a study initiated in North Rhine Westphalia (Heinsberg)
demonstrates that the number of persons with prior SARS-CoV-2–infection exceeds that of
individuals diagnosed and registered for acute infection by a factor of ten. Similar data is
obtained from still ongoing studies on the prevalence of SARS-CoV-2 specific antibodies in the
population of the Oberpfalz region in Germany (personal communication, Prof. Dr. B. Schmidt,
University of Regensburg). One study estimates the proportion of registered infected persons
at 9.2 % [18]. Thus, actually about 11 times more individuals are infected as compared to the
number reported as infected. A similar situation was observed with the COVID-19 outbreak that
occurred on board of the cruise ship Diamond Princess in spring 2020. Of all 3711 people on
board (passengers and personnel), 712 were diagnosed as SARS-CoV-2 infected of which 410
Committee on Biological Agents (Ausschuss für Biologische Arbeitsstoffe, ABAS) – www.baua.de/abasCommittee on Biological Agents (ABAS) – Decision 1/2020 update of 1 October 2020 Page 3
Classification of SARS-CoV-2 as a risk group 3 biological agent
(58 %) persons showed no symptoms at the time of testing [19]. Therefore, it is highly probable
that a significant number of SARS-CoV-2 infected individuals remain asymptomatic or do not
develop severe COVID-19.
This recent data confirms and justifies the assignment of SARS-CoV-2 to risk group 3 of biological
agents. As opposed to this, neither epidemiological nor clinical data requires and justifies an
assignment to risk group 4. Classification in risk group 2 could be reconsidered in the future if
protective vaccines or antiviral therapies become available.
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Committee on Biological Agents (Ausschuss für Biologische Arbeitsstoffe, ABAS) – www.baua.de/abasCommittee on Biological Agents (ABAS) – Decision 1/2020 update of 1 October 2020 Page 5
Classification of SARS-CoV-2 as a risk group 3 biological agent
22. TRBA 450 “Criteria for the classification of biological agents”:
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rules/Rules/TRBA/pdf/TRBA-450.pdf?__blob=publicationFile&v=2
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