2. Learning objectives
Definition of Surveillance
Introduction of COVID-19
Objectives of surveillance
Different types of surveillance
Limitations of surveillance
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3. Definition : Surveillance
Surveillance is defined as an “ongoing, systematic collection,
analysis, interpretation, and dissemination of data regarding a
health-related event for use in public health action to reduce
morbidity and mortality and to improve health.”(1)
3
4. 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 for present pandemic of COVID -19 is SARS CoV2 which is a
novel corona virus.
• Transmission of coronavirus can occur via respiratory secretion.
• The incubation period for COVID-19 is thought to extend to 14 days, with a
median time of 4-5 days from exposure to symptoms onset.(2)
• Most common symptoms are fever, fatigue, dry cough, sore throat and breathing
difficulty. Gastrointestinal symptoms include diarrhea and nausea/vomiting.
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5. Definitions to learn
Case definition
1. Suspect case
2. Probable case
3. Laboratory confirmed case
Contact definition
1. High risk contact
2. Low risk contact
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6. Suspect case
Acute onset of two or more of the following symptoms
8.Sore throat
9.Running nose
10.Shortness of breath
11.Loss of appetite in adults
12.Nausea/vomiting
13.Diarrhoea
14.Altered mental status.(3)
1.Fever with or without chills
2.Cough
3.Loss of taste
4.Loss of smell
5.General weakness
6.Headache
7.Myalgia
6
7. Probable case
A. A suspect case who is a contact of a confirmed case OR
epidemiologically linked to a cluster of confirmed cases
OR
B. An asymptomatic person who is a high risk contact of a confirmed case
OR epidemiologically linked to a cluster of confirmed cases
OR
C. If clinically suspected by a physician
OR
D. Death, not otherwise explained, in an individual with respiratory
distress preceding death AND who was a contact of a probable or
confirmed case or epidemiologically linked to a cluster of confirmed
cases.(3)
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8. Laboratory confirmed case
A person with laboratory confirmation of Covid-19
infection, irrespective of clinical signs and symptoms.(3)
8
9. Definition of a Contact
A contact is a person that is involved in any of the following:
Providing direct care without proper personal protective equipment (PPE)
for COVID-19 patients
Staying in the same close environment of a COVID-19 patient (including
workplace, classroom, household, gatherings).
Traveling together in close proximity (1 m) with a symptomatic person who
later tested positive for COVID-19.(4)
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10. High risk contact
Person who touched body fluids of a patient.
Person who had direct physical contact with the body of a patient including
physical examination without PPE.
Touched or cleaned the linens, clothes, or dishes of a patient.
Lives in the same household as the patient.
Anyone in close proximity (within 3 ft) of the confirmed case without
precautions.
Passenger in close proximity (within 3 ft) of a conveyance with a symptomatic
person who later tested positive for COVID-19 for more than 6 hours.(4)
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11. Low risk contact
• Person who shared the same space (Same class for school/worked
in same room/similar and not having a high risk exposure to
confirmed or suspect case of COVID-19).
• Person who travelled in same environment (bus/train/flight/any
mode of transit) but not having a high-risk exposure.(4)
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12. 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.
Monitor longer term epidemiologic trends and monitor trends in covid-19
deaths.
Evaluate the impact of the pandemic on health care systems and society.
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13. Different types of surveillance
Active surveillance : House to house search to identify suspect cases
Passive surveillance : Data collected from patients themselves reporting
to health facilities
Sentinel surveillance : A method for identifying missing cases and
supplementing the notified cases.(5)
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14. COVID-19 : Active surveillance
The residential areas were
divided into sectors for
ASHAs/ANMs/AWWs each
covered 100 houses
They performed active house to house visit daily
for line listing family members and those having
symptoms and also contacts of the confirmed
cases and informed higher officer,
The suspects were isolated.
The higher officer collect data from health
workers, collate and provide the cumulative
data to the control room by 4 pm daily,and also
visit houses, make arrangements for suspect
cases to designated treatment facility.(6)
District level
The control room in turn
inform the officer for
surveillance of contacts
State/National level
In the initial phase of COVID-19
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15. Containment zone and buffer zone
The containment zone is defined based on
• Index case or cluster which will be the
designated epicenter
• Geographical distribution of cases
around epicenter
• Local administrative boundaries of
urban town/city
Buffer zone
Buffer Zone is an area around the
Containment Zone, where new cases most
likely to appear.(7)
15
16. Activity in containment zone
Isolation and quarantine
Enhanced IEC
Ban local mass gathering
Closure of schools, offices, colleges
Environment disinfection
Control room establishment
Mobile specimen collection units
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18. COVID- 19 : Passive surveillance
In the initial phase of pandemic
All health facilities in the containment zone and buffer zone were listed as a
part of mapping exercise.
Such facilities reported clinically suspect cases of COVID-19 on real time basis
(including ‘Nil’ reports) to the control room at the district level
After community transmission, individual case identification, contact tracing,
and quarantining were no longer necessary.
Now, Surveillance of COVID-19 is going on for ILI (Influenza Like Illness) / SARI
(Severe Acute Respiratory Illness) cases in health facilities or outreach mobile
units or through fever clinics.
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19. Sentinel Surveillance :
To monitor the trend in prevalence of SARS-COV2 infection at district level
Sentinel group
• Low risk population: Outpatient attendees (non-ILI patients) and
pregnant women
• High risk population: health care workers
Sentinel grp
Throat/nasal
swabs for RT-PCR
tests
Blood samples for
IgG antibodies for
ELISA testing.
Collection and analysis
Data on demography collected, analyzed locally for action using
standard indicator(person, place, time)and for trend analysis.(8)
10 health
facilities/
Distric
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21. Hospital based surveillance
21
No of new confirmed cases hospitalized
No of confirmed cases discharged or
recovered
No of deaths among confirmed cases
Percent of hospital or ICU beds occupied
Proportion of hospitalized COVID-19 cases
No of confirmed cases among HCW
No of confirmed case deaths among HCW
Estimate of excess mortality
Patients with confirmed COVID-19
admitted to hospital or death should be
notified to national public health
authorities within 24 hours of
identification
22. Laboratory based surveillance :
Lab confirmed cases reported within 24 hrs
Both for NAAT (nucleic acid amplification test)
and Rapid antigen test.(9)
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23. Digital surveillance
• Digital surveillance systems are helpful
in disease containment during pandemic
• In India Aarogya Setu mobile app is a
COVID- 19 tracking app
• It helps in contact tracing
• It also help identification and prevention
of potential risk of infection
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24. COVID-19 recent situation in India (10,11)
Active cases 741830
Deaths 165101*
* COVID-19 INDIA as on : 05 April 2021, 08:00 IST (GMT+5:30) https://www.mohfw.gov.in/#
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25. Limitations of surveillance :
o Mild and sub-clinical cases are usually not seeking treatment
o Mild cases usually avoid hospital unless it is necessary
o The clinically detected cases represent only the tip of ice-berg
of the actual infected Covid-19 cases
o Lack of timeliness and completeness of reports are other
problems
25
26. References :
1. (CDC. Updated guidelines for evaluating public health surveillance systems. MMWR 2001;50 (No. RR-13)
2. CDC. Healthcare Workers [Internet]. Centers for Disease Control and Prevention. 2020 [cited 2021 Feb 4]. Available from:
https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-guidance-management-patients.html
3. 53461816061605246727.pdf [Internet]. [cited 2021 Feb 4]. Available from:
https://ncdc.gov.in/WriteReadData/l892s/53461816061605246727.pdf
4. 45899555761592998400.pdf [Internet]. [cited 2021 Feb 4]. Available from:
https://ncdc.gov.in/WriteReadData/l892s/45899555761592998400.pdf
5. Park K. Textbook of Preventive and Social Medicine. 25th edition: Bhanot Publishers;(2019)page 47
6. UpdatedContainmentPlanforLargeOutbreaksofCOVID19Version3.0.pdf [Internet]. [cited 2021 Feb 4]. Available from:
https://www.mohfw.gov.in/pdf/UpdatedContainmentPlanforLargeOutbreaksofCOVID19Version3.0.pdf
7. ContainmentandSurveillanceManualforSupervisorsincontainmentzones.pdf [Internet]. [cited 2021 Feb 4]. Available from:
https://www.mohfw.gov.in/pdf/ContainmentandSurveillanceManualforSupervisorsincontainmentzones.pdf
8. DistrictlevelFacilitybasedsurveillanceforCOVID19.pdf [Internet]. [cited 2021 Feb 5]. Available from:
https://www.mohfw.gov.in/pdf/DistrictlevelFacilitybasedsurveillanceforCOVID19.pdf
9. 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
10. india-situation-report-53.pdf [Internet]. [cited 2021 April 5]. Available from: https://cdn.who.int/media/docs/default-
source/wrindia/situation-report/india-situation-report-53.pdf?sfvrsn=49c97b8d_4
11. Latest covid 19 india report - Google Search [Internet]. [cited 2021 April 5]. Available from:
https://www.google.com/search?q=Latest+covid+19+india+report&rlz=1C1CHBF_enIN924IN924&oq=Latest+covid+19+india+rep
ort&aqs=chrome..69i57.21266j0j4&sourceid=chrome&ie=UTF-8
12. Sentinel-Surveillance-Report-Modified.docx-1.pdf [Internet]. [cited 2021 Feb 5]. Available from: https://dhs.kerala.gov.in/wp-
content/uploads/2020/05/Sentinel-Surveillance-Report-Modified.docx-1.pdf 26
