Lesson 4: Health Information Systems and Epidemiological Surveillance

What are Health Information Systems (HIS) on mortality, morbidity and risk factors used for?

They are systems that allow estimating the SIZE and TREND of health problems in the community.

What do these systems help to do?

Identify the facts, collect data, verify, analyse (interpretation), and disseminate-distribute results and necessary recommendations.

What are the uses of Health Information Systems?

• Estimate the magnitude and trend of a health problem

• Impact assessment of interventions

• Transmit information to citizens, government and decision-makers

Where is the information taken from in health service–based HIS?

From the users of the health services.

What are examples of records in health service–based HIS?

Data from hospitals (e.g., number of beds per public hospital).

What are examples of surveys in health service–based HIS?

Surveys on hospital morbidity (e.g., number of patients under surgical treatment).

What are notifying systems in health services HIS?

Mandatory notifying diseases, drugs abuse, induced abortion (voluntary pregnancy interruption).

Where is the information taken from in population-based HIS?

From each individual or a representative sample.

What are examples of records in population-based HIS?

Mortality, births, late fetal deaths, diseases.

What are examples of surveys in population-based HIS?

• Interview surveys (national health survey, surveys on disabilities, drug abuse, behaviours related to health)

• Medical exams

• General population surveys (active population survey)

What are notifying systems in population-based HIS?

Victims of traffic accidents, work accidents, professional diseases.

Questionnaire

research tools used to collect data on health, exposures, and risk factors from individuals or populations to study disease patterns and their causes

What is reliability (fiabilidad)?

The ability to reproduce the same results when we repeat the questionnaire.

What is validity (validez)?

The ability to measure what we intend to measure.

What is a pilot test?

A pilot trial.

MANDATORY NOTIFICATION DISEASEs

What does mandatory reporting refer to?

New cases of these diseases seen during the week.

What is the time unit for mandatory reporting?

The week.

What are the reporting modalities?

Manual and computerised survey.

Who reports mandatory notification diseases?

Reporting is by primary and specialised care upwards to the Ministry of Health.

EPIDEMIOLOGICAL SURVEILLANCE SYSTEM (ES)

What are the objectives of an Epidemiological Surveillance System?

• Identify health problems

• Guidance and stimulation of public health interventions

• Suggesting hypotheses for epidemiological research

• Information planning and dissemination

What is the usefulness of epidemiological surveillance?

It contributes to the prevention and control of disease and is used to determine whether a disease previously considered unimportant becomes important.

What are the qualitative attributes of an ES?

Simplicity, flexibility, acceptability.

What are the quantitative attributes of an ES?

Sensitivity, representativeness, fast, cost.

OUTBREAK OR EPIDEMIC SITUATION

What situations lead to an epidemic outbreak?

• Relevant increase in the number of cases in relation to expected values

• Appearance of a disease, health problem or health risk in an area until then free of

• Presence of any relevant event of collective acute intoxication due to accident, handling or consumption

• Occurrence of a catastrophe that can affect community health

OUTBREAK INVESTIGATION

What must be included in the clinical definition of a case?

Laboratory diagnostic criteria.

What are the classifications of cases in an outbreak?

• Suspicious: compatible with clinical definition (symptoms)

• Probable: compatible with clinical definition AND epidemiologically related to a confirmed case or coming from an endemic area

• Confirmed: compatible with clinical definition AND confirmed by the laboratory

What do methods of surveillance include in an outbreak?

Mode of notification (numeric and/or nominal, individualized, urgent, weekly, using a notification chart) and the possibility of using an epidemiological card to provide complementary information.

What do control methods include in an outbreak?

Preventive measures and control of patients, contacts and environment: ISOLATION, VACCINATION, PROPHYLAXIS.