COVID-19 and the Public Health Disease Investigation Process

posted by Colette Rossiter on Thursday, April 16, 2020

Iowa’s public health system plays a critical role in monitoring and investigating infectious diseases. Clay County Public Health Nurse Colette Rossiter responds to a number of questions people have asked about the role of public health, particularly related to the current COVID-19 pandemic.

What happens when a case of a disease such as COVID-19 is reported to public health?
Certain diseases, if not controlled, may endanger the health of the public. Because of this, Iowa law mandates that these diseases be reported to and investigated by public health. COVID-19 is the newest disease on that list.

When a case of a disease such a COVID-19 is reported to us through our state health department (Iowa Department of Public Health), we:

Notify the healthcare provider who ordered the test, who in turn calls the patient to inform them of the positive result.
If COVID-19, the healthcare provider is asked if appropriate personal protective equipment was used when assessing and testing the patient.
Conduct a case investigation.

What does a case investigation involve?
Through an interview with the case (patient), we gather information to help us:

Determine possible sources of the case’s infection.
Identify people who may be at risk of contracting the illness.
Provide the case with guidance and education regarding prevention of further spread.

Describe the types of questions you ask when interviewing the patient?
Since our goal is to stop or minimize further spread of disease, we ask questions that will help us achieve that. For COVID-19, typical questions include:

When did your symptoms begin?
What specific symptoms did you have? Are you still experiencing symptoms?
Do you have any preexisting conditions?
Did you travel anywhere in the past 14 days?
What is your occupation?
Did you work after your symptoms started or during the 48 hours before experiencing symptoms?
Who are you household contacts? Do any of them have similar symptoms?

An important part of this interview is education. For COVID-19, we review isolation at home guidance for the patient and household contacts. We reinforce prevention measures such as distancing from others in the home, hand washing, and frequent cleaning of high touch surfaces.

Does your process change based on the type of infectious disease and its specific nature?
Each disease has specific modes of transmission, infectious periods, etc. So investigations are uniquely tailored to each disease. However, the goals of containment and control remain the same.

After initial steps, what are some longer term steps?
For COVID-19, in particular, we want to assess for recovery. So we will contact the case 7 days after symptoms started to see if they are well and have met the criteria to discontinue isolation. If they have not, we will continue to call them every 3 days until the conditions are met. This also gives us an opportunity to visit with the patient and answer any questions they may have. At the state level, epidemiologists analyze the information we gathered during the interview to help “connect the dots” and apply further control measures, if needed to slow the spread.

How far out do you reach to people who may have been in contact with the patient?
Each disease we investigate is different in terms of the scale of contact tracing. During the interview, we identify those at greatest risk of becoming infected. In Iowa, we know that household contacts and healthcare workers have largely been affected by COVID-19. And more recently, we have seen outbreaks in long-term care facilities and large meat packing plants. Overall, our focus is on risk. So, at this time, we do not track everywhere the case has been, yet zero in on identification of those at greatest risk of contracting the disease.

In addition, we balance the public’s “need to know” with patient privacy. Confidentiality is extremely important and a legal requirement. We would look at expanding our notification processes if/when it is needed to protect the health of the public.

Many people may recall a few years ago when we had a measles case in the area and through public health, we shared where the infected person had been during their infectious period. Can you address how and why sharing of the first identified COVID patient was different?
COVID-19 and measles are very different in their levels of contagiousness and modes of transmission. Measles is one of the most highly infectious diseases. Even though both diseases are spread through respiratory droplets, measles is airborne and can remain infectious in the air for up to 2 hours after an infectious person leaves an area! So with the case of measles, it was important to make public notifications of the places where the case had been during the infectious period due to the nature of that disease.

How has the coronavirus pandemic been similar to other public health incidents you’ve managed over the years? How has it been different?
About 10 years ago, we experienced another pandemic: The H1N1 (swine flu) influenza pandemic. Similarly, the virus caused respiratory illness, was novel, and no one had immunity to it. However, H1N1 influenza was a “flu”. We have experience with flu. So a vaccine was able to be developed fairly rapidly (about 5-6 months). In addition, because it was a flu, many older adults had some level of immunity based on the fact that they had received annual flu shots for several years.

What are you seeing in the community that is beneficial to addressing this pandemic? What are you seeing that community members should be doing differently?
Social distancing practices are working! Our community has taken their responsibility seriously. We have only had 2 confirmed cases of COVID-19, yet we don’t want to let our guard down. Testing is still limited due to a national shortage of testing materials. Confirmed cases continue to increase in the state as a whole. With that said, there are still few reminders for everyone:

Stay home as much as possible; limit outings only to what’s unavoidable
Distance yourself from others (at least 6 feet) when out doing essential tasks
Send ONE person to the grocery store
Wear a cloth mask when out to protect others from YOU (you may have the virus but no symptoms)
Continue to wash your hands and clean high touch surfaces frequently.

coronavirus