Communicable diseases prioritized for surveillance and epidemiological research: results of a standardized prioritization procedure in Germany, 2011.

Abstract

To establish strategic priorities for the German national public health institute (RKI) and guide the institute's mid-term strategic decisions, we prioritized infectious pathogens in accordance with their importance for national surveillance and epidemiological research.
We used the Delphi process with internal (RKI) and external experts and a metric-consensus approach to score pathogens according to ten three-tiered criteria. Additional experts were invited to weight each criterion, leading to the calculation of a median weight by which each score was multiplied. We ranked the pathogens according to the total weighted score and divided them into four priority groups.
127 pathogens were scored. Eighty-six experts participated in the weighting; "Case fatality rate" was rated as the most important criterion. Twenty-six pathogens were ranked in the highest priority group; among those were pathogens with internationally recognised importance (e.g., Human Immunodeficiency Virus, Mycobacterium tuberculosis, Influenza virus, Hepatitis C virus, Neisseria meningitides), pathogens frequently causing large outbreaks (e.g., Campylobacter spp.), and nosocomial pathogens associated with antimicrobial resistance. Other pathogens in the highest priority group included Helicobacter pylori, Respiratory Syncytial Virus, Varicella zoster virus and Hantavirus.
While several pathogens from the highest priority group already have a high profile in national and international health policy documents, high scores for other pathogens (e.g., Helicobacter pylori, Respiratory syncytial virus or Hantavirus) indicate a possible under-recognised importance within the current German public health framework. A process to strengthen respective surveillance systems and research has been started. The prioritization methodology has worked well; its modular structure makes it potentially useful for other settings.

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Communicable Diseases Prioritized for Surveillance and
Epidemiological Research: Results of a Standardized
Prioritization Procedure in Germany, 2011
Yanina Balabanova1*, Andreas Gilsdorf1, Silke Buda1, Reinhard Burger1, Tim Eckmanns1, Barbara
Ga ¨rtner2, Uwe Groß3, Walter Haas1, Osamah Hamouda1, Johannes Hu ¨bner4, Thomas Ja ¨nisch5, Manfred
Kist6, Michael H. Kramer7, Thomas Ledig8, Martin Mielke1, Matthias Pulz9, Klaus Stark1, Norbert
Suttorp10, Uta Ulbrich11, Ole Wichmann1, Ge ´rard Krause1
1Robert Koch Institute, Berlin, Germany, 2Institute of Microbiology and Hygiene, University of Saarland, Homburg, Germany, 3Department of Medical Microbiology,
University of Go ¨ttingen, Go ¨ttingen, Germany, 4Division of Infectious Diseases, University Medical Center Freiburg, Freiburg, Germany, 5Department for Infectious
Diseases, Section Clinical Tropical Medicine, University of Heidelberg, Heidelberg, Germany, 6Institute for Medical Microbiology and Hygiene, University of Freiburg,
Freiburg, Germany, 7Division for Communicable Diseases, AIDS and Prevention of Epidemics, Federal Ministry of Health, Berlin, Germany, 8Family Practice ‘‘Dr. Thomas
Ledig und Jansen Rolf’’, Ditzingen, Germany, 9Governmental Institute of Public Health of Lower Saxony, Hannover, Germany, 10Department of Infectious Diseases and
Respiratory Medicine, Charite ´ University Medicine Berlin, Germany, 11Dortmund Regional Health Authorities, Dortmund, Germany
Abstract
Introduction: To establish strategic priorities for the German national public health institute (RKI) and guide the institute’s
mid-term strategic decisions, we prioritized infectious pathogens in accordance with their importance for national
surveillance and epidemiological research.
Methods: We used the Delphi process with internal (RKI) and external experts and a metric-consensus approach to score
pathogens according to ten three-tiered criteria. Additional experts were invited to weight each criterion, leading to the
calculation of a median weight by which each score was multiplied. We ranked the pathogens according to the total
weighted score and divided them into four priority groups.
Results: 127 pathogens were scored. Eighty-six experts participated in the weighting; ‘‘Case fatality rate’’ was rated as the
most important criterion. Twenty-six pathogens were ranked in the highest priority group; among those were pathogens
with internationally recognised importance (e.g., Human Immunodeficiency Virus, Mycobacterium tuberculosis, Influenza
virus, Hepatitis C virus, Neisseria meningitides), pathogens frequently causing large outbreaks (e.g., Campylobacter spp.), and
nosocomial pathogens associated with antimicrobial resistance. Other pathogens in the highest priority group included
Helicobacter pylori, Respiratory Syncytial Virus, Varicella zoster virus and Hantavirus.
Discussion: While several pathogens from the highest priority group already have a high profile in national and
international health policy documents, high scores for other pathogens (e.g., Helicobacter pylori, Respiratory syncytial virus
or Hantavirus) indicate a possible under-recognised importance within the current German public health framework. A
process to strengthen respective surveillance systems and research has been started. The prioritization methodology has
worked well; its modular structure makes it potentially useful for other settings.
Citation: Balabanova Y, Gilsdorf A, Buda S, Burger R, Eckmanns T, et al. (2011) Communicable Diseases Prioritized for Surveillance and Epidemiological Research:
Results of a Standardized Prioritization Procedure in Germany, 2011. PLoS ONE 6(10): e25691. doi:10.1371/journal.pone.0025691
Editor: Igor Mokrousov, St. Petersburg Pasteur Institute, Russian Federation
Received July 5, 2011; Accepted September 8, 2011; Published October 4, 2011
Copyright: ? 2011 Balabanova et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: The study was funded internally by Robert Koch Institute. The funders had no role in study design, data collection and analysis, decision to publish, or
preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
* E-mail: lenzy@rki.de
Introduction
The large number of infectious agents with different pathogen-
specific, host-specific and socio-economic characteristics makes the
allocation of the limited resources available within the area of
prevention and control of communicable diseases both challenging
and controversial. The amount of attention, efforts and funds spent
on surveillance, control and research of infectious pathogens varies
greatly between pathogens, settings and over time. This distribution
often appears to be ambiguous, potentially guided by senior leaders’
research interests, short-term political agenda or residuals of historic
situations [1]. As many pathogens are potentially harmful for
humansandmaypresentseriouspublichealththreats,itisnecessary
to prioritize the resources dedicated for surveillance and epidemi-
ological research of infectious diseases. This needs to be done
sensibly and rationally bearing in mind different aspects of
pathogens’ characteristics, their impact on societies and long-term
consequences of their presence or introduction into populations.
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The rational and transparent setting of priorities for investment
into health research is therefore becoming an essential part of
research planning [2–4]. Usefulness of prioritization, irrespective
of its methodology, has been demonstrated by several research
groups [5–11]. Prioritization can provide directions for future
resource allocation and strategic planning at different levels
(institutional, regional, national or international) and act as a
platform for inter-disciplinary debate involving decision-makers,
researchers, clinicians and the general public [8,12].
Although today there are a number of published tools to guide
the process of setting priorities, only a few publications openly
describe the methodology in sufficient detail and transparency to
allow reproducibility or adaptation in other settings [2,3,8,13].
Furthermore, very little is published in terms of actual prioritiza-
tion results.
The Department for Infectious Disease Epidemiology of the
Robert Koch Institute (RKI), German national public health
institute, is in charge of national surveillance, prevention, control
strategies and epidemiological research in the field of infectious
diseases. Together with external senior experts the Department
initiated a prioritization process aiming to (1) develop a rational
system for setting priorities in the area of infectious diseases using a
metric-consensus approach, and (2) rank most common pathogens
in accordance with their importance for national surveillance and
epidemiological research to guide future work of the RKI.
Methods
In the absence of established standards we designed a
methodology using elements of our previous work in 2004
[14,15] and experiences of other groups [2,3,10,11,13]. Our
multi-staged prioritization process included compilation of the list
of pathogens to be prioritized, development of evaluation criteria,
weighting of criteria and scoring of the pathogens. The
methodology was based on the core domain for good practices
in setting priorities for research in health, such as legitimacy and
fairness [3,8], and represents the further development of the work
from 2004.
Delphi process participants
The core team (YB, AG, GK) contacted relevant leading
national public health institutions with the request to name a
representative to take part in the Delphi consensus process that
aimed at assessing the feasibility of the methodology and the
relevance of the suggested criteria, as well as to discuss possible
improvements and pathogens’ scores. Ten external senior experts
(BG, UG, JH, TJ, MK, MKr, TL, MP, NS, UU) were nominated.
They represented the National Committee of Infectious Disease
Epidemiology, the German Society of Hygiene and Microbiology,
the German Society of Infectious Disease Specialists, the German
Society of Epidemiologists, the National Reference Laboratories,
the German Federal Ministry of Health, the RKI Scientific
Committee, the German Federal Chamber of Physicians and the
German Medical Association. Ten internal experts (GK, AG, YB,
SB, RB, TE, OH, KS, OW, MM) represented units and
departments of the RKI working in the field of infectious diseases.
The participants shared expertise in bacteriology, virology,
mycology, parasitology, general infectious diseases, tropical
medicine, general medicine, epidemiology, public health, veteri-
nary health and infection control.
Selection of pathogens
Tomaintainabroaderapproach,wedecidedtoevaluatepathogens
rather than diseases for their importance. A list of pathogens was
compiled according to the following selection criteria: (a) notifiable
accordingtotheGermanlawforthecontrolofinfectiousdiseases[16],
(b) reportable within the European Union [17], (c) reportable to the
WHO under the International Health Regulations [18], (d) agents
with potential for deliberate release [19], and (e) pathogens
represented in dedicated chapters in an established infectious diseases
manual [20] and occurring in Germany. Some pathogens were
grouped together when biologically and clinically plausible. The list of
pathogens was reviewed by the RKI experts and the Delphi process
participants.
Prioritization criteria and scoring
The twelve criteria used during our previous prioritization
process in 2004 [14,15] were further modified according to the
feedback received from a broad group of different experts [21].
The newly suggested criteria and their three-tiered definitions
were then reviewed by internal and external experts. The initial
scoring of all pathogens according to each criterion was performed
by the core team and internal experts from the RKI. The data
supporting the scoring decisions and references to the data sources,
or experts’ own explanations were recorded in a structured format.
The internal scoring was followed by a modified two-round Delphi
consensus process (internal round with RKI and joint round with
additional external experts) where scores were discussed.
Weighting
Independent of the scoring, we invited a panel of external
experts to assign a weight to each criterion. This invitation was
sent to all 16 federal public health institutions, all 18 national
reference centers, 49 consulting laboratories, 9 scientific and
professional societies working in the area of control, prevention
and research of infectious diseases and to all 72 participants of the
2006 online survey [21]. External experts were asked to assign a
value ranging from 0 to 10 to each criterion, thus reflecting the
criterion’s contextual importance for surveillance and epidemio-
logical research. The value 0 reflects the lowest and 10 the highest
level of importance of a criterion. More than one criterion could
be assigned the same weight, similarly to techniques used in other
prioritization exercises [5]. The final criterion’s weight was defined
by the median value of all weights assigned by the participating
experts.
Ranking of the pathogens
Each score was multiplied by the weight for the respective
criterion. The sum of these weighted scores reflects the total
weighted score of a pathogen. The total weighted scores were
finally re-scaled to a range from 0 to 100 in order to facilitate final
interpretation.
Following the experience from Canada [11], we did not focus
on the exact numerical score assigned to a pathogen. The
interpretation of the final weighted scores and their corresponding
sequential ranks was done in priority groups reflecting four priority
levels (the highest, high, medium and low priority). The cut-off
limits for the groups were based on the equal ranges of 25 (0–25,
26–50, 51–75, 76–100). Distribution of the pathogens was later
compared with their positions in the 2004 priority list.
Results
Selection of pathogens and scoring
In total 127 pathogens were selected for prioritization. Drug-
resistant strains were scored under the common pathogen group
and were not assessed as a separate entity. During the Delphi
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rounds, changes in pathogens’ scores were made based on the
consensus approach.
The Delphi process also resulted in the recommendation to
remove the criterion ‘‘Emerging potential’’ due to its ambiguous
meaning (i.e. each infectious pathogen has an ability to emerge or
re-emerge) and to rephrase the definitions of some criteria. The
final criteria and their definitions are presented in Table 1. The
detailed scores are available in the Table S1.
Criteria weighting
All criteria were weighted by a total of 86 experts (14 RKI and
72 external experts). All Delphi discussion participants took part in
the weighting.
The opinions regarding importance of individual criteria varied
greatly across the participants for some criteria, while it was similar
for others. For example, eleven participants considered the
criterion ‘‘Public attention’’ to be of a low importance (scoring it
‘‘2’’) and the same number considered it to be of a relatively high
importance (scoring it ‘‘6’’). At the same time, other criteria such
as ‘‘Case fatality rate (CFR)’’ and ‘‘Trend’’ were weighted in a
similar way by the majority of the respondents. When looking at
the median weights, the criterion ‘‘Case fatality rate’’ was
considered the most important criterion (median weight of ‘‘9’’)
while ‘‘Trend’’ and ‘‘Public attention’’ (both with a median weight
of ‘‘5’’) were considered the least important ones (Table 2).
We analyzed weights assigned by the experts working in
different areas of medicine: epidemiologists and public health
specialists (n=43), laboratory specialists (n=35) and clinicians
(n=8) (Table 2). Several criteria were assessed similarly across the
groups (for example, the criteria ‘‘Prevention’’, median weight of
‘‘8’’, or ‘‘Trend’’, median weight of ‘‘5’’). At the same time, the
criterion ‘‘Incidence’’ was seen as one of the most important by
Table 1. Prioritisation criteria and definitions of the corresponding scores.
No.Criteria
Scoring values
2 210
+ +1
1Incidence (including illness and
symptomatic infection)
,1/100 0001–20/100 000
.20/100 000
2Work and school absenteeism*
This pathogen causes a negligible
proportion of absenteeism due to
an infectious illness
This pathogen causes a small to
moderate proportion of absenteeism
due to an infectious illness
This pathogen causes a large
proportion of absenteeism due
to an infectious illness
3Health care utilization (primary
care and hospitalisation)*
This pathogen causes a negligible
proportion of health care utilization
due to an infectious illness
This pathogen causes a small to
moderate proportion of health care
utilization due to an infectious illness
This pathogen causes a large
proportion of health care utilization
due to an infectious illness
4 Chronicity of illness or sequelae*This pathogen causes a negligible
amount of chronicity or persistent
sequelae (estimate prevalence of
those being ,0.1/100 000 population)
This pathogen causes a small to
moderate amount of chronicity or
persistent sequelae (estimated
prevalence of those being
0.1–1.0/100 000 population)
This pathogen causes a large
amount of chronicity or persistent
sequelae (estimated prevalence of
those being .1.0/100 000
population)
5Case fatality rate**
,0.01%0.01–1%
.1%
6 Proportion of events requiring
public health actions (see Note
2 for explanation)**
A small proportion of the estimated total
number of events or exceptional events
require public health actions (,25%)
A moderate to large proportion of the
estimated total number of events
require public health actions (25–75%)
Almost all of the estimated total
number of events require public
health actions (.75%)
7 Trend**Diminishing incidence rates Stable incidence ratesIncreasing incidence rates
8Public attention (including
political agenda and public
perception)*
Risk perception of this pathogen by
general public is low and it is not
high on political agenda
Risk perception of this pathogen by
general public is moderate and informal
political expectations/agenda is present
This pathogen implies
international duties or its risk
perception by general public is
high or it is explicitly high on
political agenda
9 Prevention possibilities and needs
(including vaccines)**
Preventive potential seems low or the
disease does not require prevention or
effective prevention strategies are
well-established; no need for significant
strategy modification
Measures for prevention are established
but there is need to improve their
effectiveness
Need for prevention is established
but currently no effective preventive
measures are available
10Treatment possibilities and needs
(including AMR)**
Medical treatment is rarely necessary or
effective regimens are well-established;
no need for significant modifications
Medical treatment regimens are
established but there is need to
improve their effectiveness
Need for medical treatment is
established but currently no effective
treatment is available or AMR limits
treatment options
AMR=antimicrobial resistance.
Note 1. All criteria apply to the geographical settings where the prioritization is conducted; the time-frame applicable to the requested epidemiological data should be
defined prior to the process initiation and depend on a frequency with which pathogens are planned to be re-scored. The RKI conducted re-scoring relevant for
Germany using a time-frame of 5 years. Indicated numerical thresholds apply to a country where the prioritization process is conducted; when the prioritization is
conducted in other geographical settings, different thresholds may need to be considered.
Note 2. Event is defined as the occurrence of a disease that is unusual with respect to a particular time, place or circumstances. For certain infectious diseases one case
may be sufficient to constitute an event (e.g. polio virus). Public health actions are any kind of targeted actions aiming to identify the nature of the event and/or to
apply control measures in response to the event occurrence.
*assessed against the total burden of infectious diseases.
**assessed for each particular pathogen in question, e.g., for the criterion ‘‘Treatment possibilities and needs’’ it therefore refers to availability and adequacy of
treatment for each case of an illness caused by a particular pathogen and does not take into account the incidence of illnesses or the availability of preventive measures.
doi:10.1371/journal.pone.0025691.t001
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epidemiologists and public health experts (median weight of ‘‘8’’)
and laboratory specialists (median weight of ‘‘7’’) but was seen as
one of the least important by clinicians (median weight of ‘‘5.5’’).
Almost the reverse situation was observed with the criteria ‘‘Work
and school absenteeism’’ and ‘‘Health care utilization’’ that were
seen to be important by clinicians but perceived as of lower
importance by the two other groups.
Pathogen ranking
Table 3 presents the allocation of the pathogens into four
priority groups according to their weighted total score. The highest
priority group contains 26 (20.5%) pathogens. Among those are
the pathogens that already received the highest priority in our
previous prioritization process, such as HIV, Mycobacterium
tuberculosis, Staphylococcus aureus including methicillin resistant strains
(MRSA), Influenza virus, Hepatitis C virus, Campylobacter spp.,
Neisseria meningitidis, Legionella pneumophila, Varicella zoster virus
(VZV). It additionally contains a number of pathogens responsible
for nosocomial infections (e.g., Klebsiella spp., Pseudomonas ssp.,
Enterococcus spp.) and Respiratory syncytial virus (RSV) that were
not evaluated by us previously. Helicobacter pylori and Hantavirus
now belong to this group, while in 2004 both pathogens held
medium priority positions. Other pathogens that were scored
highest in 2004 were now assessed to be in the medium priority
group (e.g., Parvovirus B19).
The high priority group contains 39 (30.7%) and the medium
priority group - 45 (35.4%) pathogens. A number of pathogens
that were ranked as the least important in 2004 (Vibrio cholera,
Francisella tularensis, Bacillus anthracis, Bartonella quintana) were now
assigned to the medium and high priority groups.
Out of 17 pathogens from the low priority group in 2011, 11
were newly added.
Discussion
This prioritization approach allowed us to benefit from the
cumulative knowledge of many experts. The results of our work
seem convincing to us; they support our current activities as well as
indicate new directions for the future work. For example, the
ranking of the majority of the pathogens found in the highest
priority group (e.g., HIV, M.tuberculosis, Influenza virus, Neisseria
meningitides, Legionella pneumophila) is in line with strategic goals
identified by a number of international agencies that focus both on
resource-constrained health systems and on industrialized coun-
tries such as Germany [4,9,22–24]. The decision to evaluate a
broad range of nosocomial pathogens in the current prioritization
and their high ranks indicate a growing recognition of the problem
of antimicrobial resistance and healthcare associated infections
(HAI) and are in line with a number of new strategic international
and national policies calling for enhancement of HAI surveillance
activities and capacities [4,25].
The positioning of Helicobacter pylori, Hantaviruses, RSV and
VZV among the pathogens in the highest priority group helped us
to identify the under-recognized importance of the diseases with
respect to surveillance and epidemiological research and call for
actions in this respect.
Indeed, although there is a large amount of clinical and
laboratory research dedicated to Helicobacter pylori and a number of
clinical guidelines are available, very little is done in terms of
public health surveillance, despite the growing rates of antimicro-
bial resistance seriously compromising treatment [26,27].
RSV remains the most common respiratory pathogen in infants
and young children worldwide, often resulting in serious lower
respiratory tract infections [28], yet a routine surveillance system
for RSV based on virological testing of sentinel respiratory samples
has only been initiated recently, and the burden of disease at the
population level in Germany is largely unknown. The placement
of RSV in the highest priority group is particularly unusual as
pathogens causing diseases in limited population groups, i.e. here
in young children, are often believed to be of a lower overall
importance.
The incidence of human disease caused by Hantavirus
fluctuates significantly over time; its incidence has peaked in
endemic areas in Germany in recent years, which may have
contributed to the higher ranking of this pathogen in the 2011
prioritization and the call to enhance research activities. A
population-based seroprevalence survey will indeed be initiated
within the RKI-funded network of reference laboratories.
VZV, a virus that causes two frequent diseases in children and
adults, was ranked as a pathogen with the highest importance both
Table 2. Median weight of each criteria defined by experts from different professional groups (criteria are ranked according to
their priority positions among all participants).
Criterion All participants (n=86)
Area of professional activity
Epidemiologists and public
health specialists (n=43)Laboratory experts (n=35)Clinicians (n=8)
Case fatality rate 9.09.09.0 8.0
Prevention possibilities and needs8.08.08.0 8.0
Proportion of events requiring
public health actions
8.08.08.07.5
Chronicity of illness or sequelae 8.07.08.08.5
Incidence7.08.0 7.0 5.5
Treatment possibilities and needs
(including AMR)
7.0 6.08.07.0
Health care utilization 6.0 6.06.08.0
Work and school absenteeism 6.05.0 7.08.0
Trend 5.05.0 5.0 5.0
Public attention5.05.0 4.04.0
doi:10.1371/journal.pone.0025691.t002
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Table 3. List of pathogens in groups of priority (n=127), Germany.
Highest priority group: scores
between 76 and 100 (n=26)
High priority group: scores
between 51 and 76 (n=39)
Medium priority group: scores
between 26 and 50 (n=45)
Low priority group: scores
between 0 and 25 (n=17)
Campylobacter spp Acinetobacter Bacillus anthracisActinomycosis
Chlamydia trachomatisAdenovirusBacillus cereusAstrovirus
Clostridium difficile Arthropod-borne viral encephalitides Bartonella quintanaChlamydia pneumoniae
Escherichia coli, shiga toxin
producing (STEC/HUS)
Aspergillus spp.Bordetella pertussis Coxsackievirus
Escherichia coli (non-gastro illnesses)Brucella spp Borrelia burgdorferiCyclospora cayetanensis
Enterobacter spp. Corynebacterium ulcerans and
Corynebacterium pseudotuberculosis
Burkholderia cepaciaEntamoeba histolytica
Enterococcus spp. (blood) Prions causing Creutzfeldt Jakob Diseases Burkholderia pseudomallei and malleiFungi (other)*
Hantavirus Crimean–Congo hemorrhagic fever virusCandida spp.Helminths (flukes)**
Helicobacter pyloriCryptosporidium parvum/hominis Chlamydia psittaciHelminths (nematodes)***
Hepatitis B virusDengue fever virusCitrobacter spp.Helminths (tapeworms)****
Hepatitis C virusEarly summer meningoencephalitis virus and
other tick-borne meningoencephalitis viruses
Clostridium botulinum HHV -6 and 7 (roseolovirus)
Human immunodeficiency virus (HIV)Ebola and Marburg virusClostridium perfringens Histoplasma capsulatum
Influenza virusEnteroviruses spp. incl. echoviruses Clostridium tetaniKlebsiella granulomatis
Klebsiella spp.Epstein-Barr virus (HHV-4) CoronavirusesMolluscipoxvirus
Legionella pneumophila Giardia lambliaCorynebacterium diphtheriaeMycobacterium leprae
Measles virusHaemophilus influenzaeCoxiella burnetiiPneumocyctis jiroveci
Mycobacterium tuberculosisHepatitis A virus CryptococcosisUnidentified agent causing
Kawasaki syndrome
Neisseria meningitidisHepatitis D virusCytomegalovirus (HHV-5)
Pseudomonas ssp. Hepatitis E virusEscherichia coli, enteropathogenic
(non STEC/HUS), enterotoxigenic
strains, enteroinvasive, enteroaggregative
and diffuse-adeherence strains
Respiratory syncytial virus (RSV) Human papilloma virus (HPV) Francisella tularensis
Salmonella spp. (non-typhi and non-
paratyphi)
Lassa fever virus Herpes simplex virus (HSV)-1
Staphylococcus aureus incl. methicillin
resistant (MRSA) and Staphylococcus
aureus, toxigenic
Listeria monocytogenes Herpes simplex virus (HSV)-2
Staphylococcus epidermidis/
Coagulase-negative staphylococci
Microspora and trichophytonHHV-8 (Kaposi’s sarcoma associated)
Streptococcus pneumoniaeMumps virus Human T-cell lymphotrophic virus (HTLV)
Streptococcus spp. other than
Steptococcus. pneumoniae
Mycoplasma spp. Leishmania spp.
Varicella zoster virus (VZV) Neisseria gonorrhoeaeLeptospira interrogans
NorovirusMycobacterium, other (non-tuberculous)
Parainfluenza viruses Parvovirus B 19
Pediculosis (head, body and pubic lice)Plasmodium spp.
Polio virusRhinoviruses
Rabies virusRickettsia prowazekii, typhi and
Orientia tsutsugamushi
Rotavirus Rickettsia spp.
SARS coronovirus (SARS-CoV)Rubella virus
Toxoplasma gondiiSalmonella paratyphi and Salmonella typhi
Variola virusSarcoptes scabiei
Viruses, others causing hemorrhagic
fevers (Chikungunya, Rift Valley)
Shigella spp.
West Nile virusStenotrophomonas (Pseudomonas) maltophilia
Yellow fever virus Treponema pallidum
Yersinia enterocolitica and pseudotuberculosisTrichinella spiralis
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in 2004 and in 2011. Country-wide sentinel surveillance has been
recently implemented for VZV after the implementation of a
routine childhood Varicella vaccination program in 2004 [29].
The low priority group contains both pathogens with very low
incidence in Germany (e.g., Mycobacterium leprae or helminths)
and those much more common (e.g., Roseolovirus or Chlamydia
pneumoniae), supporting our approach that the importance of a
pathogen is defined by multiple factors rather than by its incidence
or prevalence alone. Complex surveillance systems exist for some
pathogens that were assigned to the medium priority group, for
example, Francisella tularensis or Yersinia pestis. Although the amount
of research that should be dedicated to those medium- and low-
priority pathogens must be revised, undoubtedly the need to
investigate outbreaks associated with these pathogens, to maintain
diagnostic capacity and to continue efficient surveillance to pick up
increasing trends of these rare illnesses, remains.
Similarly to other research groups that initiated processes for
setting priorities [2,8,13], we found the compilation of the data
necessary for the scoring process to be challenging due to a limited
availability of reliable and published information. Participants did
not find it easy to maintain sufficiently broad judgements despite
the highly specialized expertise and focused research interest of
some experts. Some degree of subjectivity can therefore never be
avoided. Another limitation of our study was the difficulty to
appropriately account for the decreasing trends of vaccine-
preventable diseases that followed successful implementation of
effective prevention programmes. Therefore, relatively low scoring
of the respective pathogens for some of the criteria should not
question the need to maintain adequate surveillance capacity for
these illnesses.
In the applied methodology, we aimed at following the main
principles of good practice in setting priorities in health research
[3] and to reach maximum levels of objectivity, transparency, and
reproducibility by integrating the following components: 1) a
broad but systematic and reproducible selection of pathogens,
rather than respective diseases to be included in the prioritization,
2) an explicit definition of each of the ten criteria using a three-
tiered grading approach, 3) a comprehensive individual pathogen-
specific scoring according to the best available evidence reviewed
by a multidisciplinary expert group, and 4) a separate weighting of
the criteria based on the involvement of a broad range of internal
and external experts. Although this approach required intensive
preparation, we believe it assured a high level of objectivity and
transparency as demanded by Nuyens et al [7].
Our pathogen-specific approach allowed us to conduct prioriti-
zation not influenced by programmatic views and to compare
pathogens’ ranking within a group of diseases as well as across the
groups (e.g., a pathogen being targeted by an antimicrobial
resistance programme as well as by a zoonoses programme). This
approach helped us uncover some differences in the importance of
pathogens belonging to the same group, e.g., Neisseria gonorrhoeae and
Trichomonias vaginalis.
Marked differences were observed in the weighting of the
criteria between different professional groups. As the invitation to
participate in the weighting was sent to various institutions and
often forwarded further, it is not feasible to estimate the response
rate. However, we received responses from at least one member of
each contacted institution. The weighting of criteria is likely to
correlate with societal values and reflect socio-economic, cultural
and health system structure in a country. The fact that in
Germany the criterion ‘‘Case fatality rate’’ was considered to be of
the most importance, may reflect the high level of individualiza-
tion and relative affluence of the German health care system.
Comparisons to other countries are difficult since similar studies
are lacking. One of the few other priority-setting initiatives with an
explicit weighting procedure was conducted in Spain in which the
criterion ‘‘Burden and importance of illness’’ was identified to be
among the first three most relevant from a total of nine criteria, the
other two being ‘‘Potential to change health outcomes’’ and
‘‘Potential to translate new knowledge into clinical or health
services practices’’ [5]. We can conclude that weighting needs to
be explicitly addressed in any prioritization exercise and it is
particularly appropriate for a national public health institute in
order to reflect expectations from a broad range of professionals as
the respective stakeholders [30]. One way to even expand the
societal perspective of the prioritization exercise could be to
involve patients’ representatives, similarly to how it has been done
by Gooberman-Hill et al [31], for example.
Conclusions: The prioritization methodology presented here
is based on the systematic evaluation of evidence and the
Highest priority group: scores
between 76 and 100 (n=26)
High priority group: scores
between 51 and 76 (n=39)
Medium priority group: scores
between 26 and 50 (n=45)
Low priority group: scores
between 0 and 25 (n=17)
Trichomonias vaginalis
Trypanosoma brucei gambiensi and brucei
rhodesiensi
Vaccinia virus
Vibrio cholera
Vibrios (non-cholera): V. parahaemolyticus, V.
vulnificus and V. cholerae (non O1 and O139)
Yersinia pestis
*Fungi (other) group includes: Blastomyces, Fonsecaea , Phialophora, Cladosporium, Fonsecaea, Coccidioides immitis and posadasii, Actinomyces, Sporothrix,
Paracoccidioides, Zygomycota.
**Helminths (flukes) group includes: Clonorchis sinensis, Opisthorchis felineus, Opisthorhis viverrini, Fasciolopsis buski, gigantica and hepatica, Paragonimius, Schistosoma.
***Helminths (nematodes) group includes: Ancylostoma braziliense and caninum, Angiostrongylus, Ascaris lumbricoides, Capillaria philippinensis, hepatica and aerophila,
Dranculuse meditensis, Enterobius vermicularis, Filaria (Onchocerca volvulus, Loa loa, Wuchereria bancrofti, Brugia malayi and Brugia timori). hookworms (Ancylostoma
duodenale and Necator americanus), Strongyloides stercoralis, Toxocara canis and cati, Trichuris trichiura. Trichinella spiralis was scored as a separate pathogen.
****Helminths (tapeworms) group includes: Diphyllobotrium latum, Echinococcus granulosus, Echinococcus multilocularis, Hymenolepsis nana, Taenia saginata, Taenia
solium.
doi:10.1371/journal.pone.0025691.t003
Table 3. Cont.
Communicable Diseases Prioritization, Germany
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Page 7

involvement of a broad range of external experts. We feel that the
results provide internal consistency and are plausible in the public
health perspective. Our comprehensive and transparent approach
makes the results defensible and shall give guidance for current
needs in surveillance and epidemiological research in Germany.
The list of ranked pathogens established here will serve as a
reference for our mid-term strategic decisions, which will include
strengthening the existing or introduction of new surveillance
systems for pathogens from the high priority group (e.g., RSV,
VZV or Helicobacterpylori) and re-consideration of the research and
surveillance needs for those from the lowest priority group. It has
already influenced the decision process on the need for the
installation of new and continuation of existing national reference
centers in Germany and the internal planning for the respective
allocation of resources (GK personal communication). We plan to
conduct a re-assessment of priorities within a five-year time frame
based on the same methodology. The prioritization tool or its
components can be applied across different areas of infectious
diseases (by re-weighting prioritization criteria by different
professional groups for different purposes) and in different
geographical areas (by re-scoring pathogens according to their
characteristics relevant for particular countries or continents). We
hope that the presentation of our methodology could be helpful to
other institutions that choose to prioritize their resources based on
a transparent and standardized process.
Supporting Information
Table S1
veillance and epidemiological research. Results of patho-
gen scoring.
(XLS)
Communicable diseases prioritized for sur-
Acknowledgments
We would like to thank all members of the Department for Infectious
Disease Epidemiology, RKI for useful discussions, expert consultations and
for taking part in the pathogens’ scoring: C. Adlhoch, M.Altmann,
K.Alpers, M.Askar, K.Atzpodien, B. Bartmeyer, H.Bernard, J.Benzler, J.
Bielecke, B.Brodhun, U.Buchholz, W.Cai, S.Dudareva, M.Faber, G.Falk-
enhorst, L.Fiebig, C.Frank, B.Greute ´laers, M.Dehnert, W.Haas, B.Hauer,
W.Hellenbrand, J.Hermes, M.Kang, J.Koch, K.Ko ¨pke, S.Lassen,
G.Laude, U.Marcus, D.Matysiak-Klose, A.Milde-Busch, M.Nachtnebel,
S.Nielsen, I.Noll, R.Offergeld, S.Reiter, C.Remschmidt, A.Reuß, U.Re-
xroth, T.Rieck, B.Rosner, I.Scho ¨neberg, B.Schweickert, A.Siedler, P.
Sto ¨cker, T.Su ¨ß, A.Takla, B.Ultsch, E.Velasco, L.Voß, M.Wadl, B.Weiss,
D.Werber, H.Wilking, and R.Zimmermann.
We thank as well all colleagues who took part in the weighting procedure
and Blair Prochnow for editorial support in the finalization of the
manuscript.
Author Contributions
Conceived and designed the experiments: YB AG GK. Performed the
experiments: YB AG GK SB TE WH OH KS OW RB BG UG JH TJ
M.Kist M.Kramer MM TL MP NS UU. Analyzed the data: YB AG GK
SB TE WH OH KS OW RB BG UG JH TJ M.Kist M.Kramer MM TL
MP NS UU. Contributed reagents/materials/analysis tools: YB AG GK.
Wrote the paper: YB AG GK.
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