Question

Topic: Screening for Covid-19. Epidemiology

In December 2019, cases of a severe and a unique pneumonia were recognized in Wuhan, China. Initial case definition and diagnosis required a combination of symptoms (fever, dry cough and pneumonia) and positive chest CT (computerized tomography) results. The pneumonia associated with this disease resulted in what are described as “ground glass opacities” in chest CT scans.

1. Was this case definition very sensitive or very specific? Explain your answer briefly. (3pts)

2. Would such a case definition result in an under or over estimation of case fatality, and why? (2pts)

The disease, later named CoVid-19, by the WHO was determined to be viral in origin and likely infectious by person to person contact. As concerns increased about the disease spreading screening programs at airports looked for increased temperatures and coughing in travelers. It was thought at the time only symptomatic cases were contagious.

3. Would you consider this screening to be more sensitive or more specific or neither? Explain your answer briefly. (3pts)

4. If the assumption that only symptomatic cases were contagious what would have been the advantages of this screening approach? (2pts)

Answer 1

QUESTIONS AND ANSWERS

Question .1: Was this case definition very sensitive or very specific? Explain your answer briefly. (3pts)

Answer: This case definition was very sensitive and specific to certain extent. This definition tells only peripheral information about the pandemic at the time of its emergence. Based on the given information, we can’t predict the treatment and prognosis. Hence it may become sensitive information to the public. It requires detailed data to be specific.

Question.2: Would such a case definition result in an under or over estimation of case fatality, and why? (2pts).

Answer: This definition is not much informative for the public as well as the health department to understand the severity of the disease completely. It requires thorough studies and data for the effective analysis and planning of the treatment. It requires evidenced based practice and a comprehensive approach to plan the care for this disease .This definition don’t meet those requirements. Hence such a case definition may result in an under or over estimation of case fatality.

Question .3: Would you consider this screening to be more sensitive or more specific or neither? Explain your answer briefly. (3pts)

Answer: This screening can be sensitive to an extent but not more specific. Because this screening is not adequate as it focuses only on airport, leaving other transport ways. It may create a sensitivity issue in the public as screening initiate queries about the disease and its prevention.

Question.4: If the assumption that only symptomatic cases were contagious what would have been the advantages of this screening approach? (2pts)

Answer: If only symptomatic cases were contagious, screening approach can be effective to an extent. But it should focus not only in airport, but also everywhere. If this assumption is wrong, the spread of disease may be rapid and even be fatal and this screening won’t be enough as the asymptomatic cases also become contagious.