Public health surveillance of covid 19

Public Health
Surveillance of
COVID-19
Dr. Noor Islam Bag
1st year PGT,MD(Community Medicine)
1

Learning Objectives
• 1.Epidemiology of COVID-19
• 2.Case definition
• 3.Definition of contact
• 4.Definition of COVID-19 death
• 5.Aim and Objectives of surveillance
• 6.Different Indicators of surveillance
• 7.Different types of surveillance
• 8.Chalenges & limitation of surveillance
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Epidemiology of COVID-19
• Agent- Corona virus belongs to large family of RNA viruses,some causing
infection to human and others to animals.
• The etiologic agent responsible for present pandemic of COVID -19 is SARS
CoV2 which is a novel corona virus.
• Transmission of coronavirus can occur via respiratory secretion.
• Current estimation of Incubation Period(I.P) – 2 to 14 days.
• Most common symptoms are fever,fatigue,dry cough,sore throat and breathing
difficulty.Gastrointestinal symptoms include diarrhea and nausea/vomiting.
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Case definition : Suspected case
A. AND OR
B.
C.
Clinical criteria
Epidemiological
criteria
Acute onset of fever and cough
Acute onset ANY THREE OR MORE of the following S/S
fever, cough, general weakness/fatigue, headache, myalgia,
sore throat, coryza, dyspnoea, anorexia/nausea/vomiting,
diarrhoea, altered mental status.
Residing/working in closed residential settings and humanitarian
settings, like camp and camp-like settings for displaced persons,
any time within the 14 days before symptom onset
Residing in or travel to an area with community transmission
anytime within the 14 days before symptom onset
Working in health setting, including within health facilities and
within households, anytime within the 14 days before symptom
onset.
A patient with severe acute respiratory
illness (SARI: acute respiratory infection
with history of fever or measured fever of
≥ 38 C°; and cough; with onset within the
last 10 days; and who requires
hospitalization).
An asymptomatic person not meeting
epidemiologic criteria with a positive
SARS-CoV-2 antigen-detecting rapid
diagnostic test (Ag-RDT).
OR
OR
4

Case definition: Probable case
A.
B.
C.
D.
A patient who meets clinical criteria above AND is a contact of a probable or confirmed
case or is linked to a COVID-19 cluster
A suspected case with chest imaging showing findings suggestive of COVID-19 disease.
A person with recent onset of anosmia (loss of smell) or ageusia (loss of taste) in the
absence of any other identified cause.
Death, not otherwise explained, in an adult with respiratory distress preceding death AND
who was a contact of a probable or confirmed case or linked to a COVID-19 cluster.
5

Case definition : Confirmed case
• A.
• B.
• C.
A person with a positive Nucleic Acid Amplification Test (NAAT)
A person with a positive SARS-CoV-2 Ag-RDT AND meeting either the
probable case definition or suspected criteria A OR B
An asymptomatic person with a positive SARS-CoV-2 Ag-RDT AND who
is a contact of a probable or confirmed case.
6

Definition : Contact
A contact is a person who has experienced any one of the
following exposures during the 2 days before and the 14 days
after the onset of symptoms of a probable or confirmed case:
Face to face contact with probable or confirmed
case within 1 meter and for at least 15 mnts.
Direct physical contact with a probable or
confirmed case.
Direct care for a patient with probable or
confirmed COVID-19 disease without PPE 7

Definition : COVID-19 Death
A COVID-19 death is defined for surveillance purposes as a death resulting from a
clinically compatible illness in a probable or confirmed COVID-19 case, unless
there is a clear alternative cause of death that cannot be related to COVID-19
disease (e.g. trauma). There should be no period of complete recovery between the
illness and death.
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Objectives of Surveillance
• Enable rapid detection, isolation, testing, and management of cases.
• Identify, follow-up and quarantine contacts.
• Detect and contain clusters and outbreaks among vulnerable populations.
• Guide the implementation and adjustment of targeted control measures.
Short-term
objectives
• Monitor longer term epidemiologic trends and evolution of SARS-CoV-2 virus
and monitor trends in covid-19 deaths.
• Evaluate the impact of the pandemic on health care systems and society.
• Contribute to the understanding of the co-circulation of SARS-CoV-2 virus,
influenza and other respiratory viruses, and other pathogens.
Long-term
objectives
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Different indicators for Surveillance:
• Short-term Indicators (weekly reporting -WHO ,age/sex)
No of person tested for COVID-19
No of new confirmed cases
No of new confirmed cases hospitalized
No of confirmed cases discharged or recovered
No of death in confirmed cases(CFR)
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Different indicators for Surveillance:(Cont)
Indicators to monitor longer term epidemiological trends
No of confirmed COVID-19
cases(subnational level)
Incidence rate
Percent of SARS-CoV-2 cases out of
hospitalized SARI cases
Percent of SARS- CoV-2 cases out of
outdoor ILI cases
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Indicators to monitor longer term epidemiological trends
Changes in deaths
No of COVID-19 deaths in confirmed
cases(CFR)
No of confirmed COVID-19 deaths
among hospitalized(hCFR)
Deaths of COVID-19 like illness
Estimate of excess all cause
mortality
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Changes in risk factors or co-morbidities
Percent cases with risk factors
Percent deaths with risk factors
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Indicators to Evaluate the Impact of the Pandemic on Healthcare
Systems and Society :
 No of new confirmed cases hospitalized
 No of confirmed cases discharged or recovered
 Percent of hospital or ICU beds occupied
 Percent of hospitalized confirmed COVID-19 cases
 No of confirmed cases among HCW
 No of confirmed case deaths among HCW
 Estimate of excess mortality
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Indicators to Understand the Co-circulation of COVID-
19Virus, Influenza and Other Respiratory Viruses:
Trends over time (by age, sex, region)
Percent of positive specimens for SARS-CoV-2 vs. other respiratory viruses
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Different types of surveillance:
Comprehensive routine surveillance
Testing all suspected cases
Most accurate COVID-19 indicator
Monitor trend by time/Intra country data
comparison
Impossible to apply low income,developing
country
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Different types of surveillance: (cont)
Case-based routine surveillance (reporting)
• Reporting of Probable & Confirmed cases within 48 hrs
• A update of line listing within 30 days of 1st reporting
• Low income country can apply
• Cannot be apply alone
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Different types of surveillance:(cont)
Aggregated routine surveillance:
Once weekly all countries for epidemiological trends (National level)
Weekly reporting :
1. Newly confirmed cases
2. Newly death due to COVID-19
3. New cases hospitalized
4. Discharged cases
5. Age group confirmed cases
6. Age group Deaths
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Active Surveillance: (active search of disease in certain population)
 Case findings,testing,contact tracing of all transmission cases
 All countries need quickly strenghthening active surveillance team
 Recognition,proper isolation quarantine of cases
 Contact & co-exposure identification for all recognized possible cases
 Training of public health worker and volunteers
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Syndromic (clinical) surveillance
1. Surveillance of health data according to clinical manifestation
• A suspected case
• A probable cases
• A confirmed cases
2.It helps rapid case detection by working definition
3.Information taken from surveillance utilized for making decisions about health
policy and health education
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Sentinel surveillance
1. A network of healthcare providers or hospitals are recruited to regularly report
2. Reporting units having good laboratory facilities and qualified staffs
3. Promptly understanding the magnitude of Covid-19 in certain population
3. Detection of such transmission is essential
o Notifying response actions
o Testing criteria
o Quarantine guide
o Investigation protocols
o Community mitigation actions
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Sentinel syndromic surveillance
Mild suspected cases to consult PHCP in ILI/ARI clinic for surveillance
Swabs testing done of this cases for SARS-CoV-2.
Intensity of Covid-19:
• Weekly number of positive results over all tested specimens
• Weekly number of confirmed cases over the number of ILI/ARI cases
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Laboratory based surveillance
Virological surveillance Virological sentinel surveillance ppln serologic surveillance
Lab confirmed cases
reported within 24 hrs
Both for NAAT and
Rapid antigen test
Healthcare providers
with contact,elderly
people,comorbidity,
Hospitalized SARI/ARI
cases
Using the clinical
specimens that
obtained through
national sentinel
surveillance of
ILI/ARI/SARI using
RT-PCR
Some country health care
practices contributing in
virology surveillance
collect blood samples
from persons coming for
a routine blood
testing.extra sample for
Covid-19 serology
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Hospital-based surveillance: (SARI cases)
Testing of all SARI cases admitted (ICU) / High dependency Unit of a hospital
Monitor the percentage of confirmed Covid-19 from all SARI
Sentinel hospitals chosen if catchment population well recognized/stable.
Selection of all hospitals in a given area and inhabitants of this area as denominator
Late case detection as a drawback
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Hospital-based surveillance: (nosocomial outbreak)
Covid-19 nosocomial outbreaks must be notified within 24 h of detection
Quickly manage such events, enhancing infection prevention and control measures
Contact tracing for protecting HCWs,patients,residents & health care infrastructure
Covid-19 outbreaks and the proportion of affected facilities may be used as
supplementary indicators of intensity,geographic spread,its impact on the healthcare
system
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Hospital-based surveillance
Mortality surveillance
Health care surveillance
 Hospitalised confirmed Covid-19 deaths & elderly who die in long-term care facilities
 This surveillance remains a vital tool for measuring the disease severity
 The surveillance data is also easy to collect,available and frequently updated
 Notifies the effect of Covid-19 on the capability of the healthcare system
 Information concerning the availability or lacks of essential resources as hospital beds, ICU beds,
ventilators, PPE and healthcare personnel shortages
 WHO, NGOs and rich countries can help low-income nations, according to their deficiencies, and
based on such surveillance reports
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Help-lines, surveys, participatory surveillance
 Consultations calls with sentinel doctors
 Calls to health care telephone help-lines (at regional or national levels)
 Consultations of online health care apps
 Self-assessment tools for advice on Covid-19 testing
 Low cost
 Helps in decreasing the rate of hospital-acquired infection by isolation
 Follow-up of the contact and mild cases at home
 Gives reassurance of the isolated cases as they are under supervision of
consultants
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Electronic reporting systems
 Web-based tools for reporting disease & epidemics
 Electronic record dashboards, and other electronic tools are needed to assist surveillance system
 American CDC utilizes interactive Germ data dashboard, bio-informatics in the cloud, application
programming interfaces (APIs), Fast Healthcare Interoperability Resources (FHIR), and SMART
(Substitutable Medical Apps, Reusable Technology) on Fast Healthcare Interoperability Resources
(FHIR) apps to enhance the surveillance system
 In KSA, the Health Electronic Surveillance Network (HESN) utilized rapid reporting, updating and
giving feedback about Covid-19 cases
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Digital surveillance
oUSA ankle bracelet technology to enforce quarantine among Covid-19 patients
o South Korea a GPS apparatus track the locations, send alerts to authorities
o Hong Kong authorities requires a bracelet an app for all travelers
o Social media search indexes (SMSI),China as an early predictor Covid-19 outbreak
o Singapore individuals report their locations with photographic proof
o Thailand is using an app and SIM cards for travelers to enforce their quarantine
o India is planning to manufacture location and temperature-monitoring bands
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Event-based surveillance
Robust event-based surveillance rapidly detect any changes in the overall COVID-19
situation
EBS captures unstructured information from formal and informal channels such as
online content, radio broadcasts and print media across all relevant sectors
Many web-based systems have been developed over the years to support EBS activities
 Converge through the WHO-led Epidemic Intelligence from Open Sources (EIOS)
initiative
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Challenges & limitations of surveillance
Challenges
Public health surveillance in low-resource countries differs from
surveillance in developed nations
1.More must be done with less
2.Strengthening surveillance system in developing countries is more
complicated due to deficiency of resources and lack of adequate training
3.sustainability of the surveillance is more challenging
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Challenges & limitations of surveillance
Limitations
1. There is major under ascertainment/under reporting of total Covid-19 cases
from different countries
2. There is still uncertainty due lack of big longitudinal studies and clinical trial
3. Mild and sub-clinical cases are usually not seeking treatment
4. The testing capacity may limited for only severe cases
5. Mild cases usually avoid hospital unless it is necessary
6. The clinically detected cases represent only the tip of ice-berg of the actual
infected Covid-19 cases
7. Generalized under-detection of the imported cases is another limitation
8. Lack of timeliness and completeness of reports are other problems 32

References:
• 1. Ibrahim NK. Epidemiologic surveillance for controlling Covid-19 pandemic: types, challenges and
implications. J Infect Public Health. 2020;13(11):1630–8.
• 2. Public health surveillance for COVID-19: interim guidance [Internet]. [cited 2021 Jan 24]. Available
from: https://www.who.int/publications-detail-redirect/who-2019-nCoV-surveillanceguidance-2020.8
• 3. COVID-19: What You Need to Know [Internet]. [cited 2021 Jan 24]. Available from:
https://webcache.googleusercontent.com/search?q=cache:aVRxYFcxaegJ:https://www.cdc.gov/coronavirus/2
019-ncov/downloads/global-covid-19/surveillance-strategies-human-
infection.pdf+&cd=15&hl=en&ct=clnk&gl=in
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