These days, everyday people are taking on hero status. 
University of Tennessee at Chattanooga Master of Public Health graduate student Jasmine Pulliam is no exception. 

In order to gather information for the health department, the Chattanooga native has been working from home, checking on people who have come into contact with someone who tested positive for COVID-19.

None of the people being interviewed by Pulliam actually have the virus; the goal is to track whether they eventually show symptoms or not. From there, Hamilton County Health Department officials can determine where the virus might have previously been, where it might spread and the number of patients suffering from it.

Pulliam has five subjects to call daily, and said they have been “very calm and aware” of the situation.

“They are very cooperative and open to answering questions,” she said.
Pulliam joins UTC graduate student Mary Ferris, along with athletic training students and faculty in the Department of Health and Human Services, as they touch base daily with people who have had contact with someone ill with coronavirus.

Dawn Ford, clinical associate professor with the Master of Public Health program at UTC, trained 61 volunteers on procedures, which were developed by the Hamilton County Health Department.

From there, health department officials get in touch with her when they have people that need tracking, Ford explained.

“I assign the contacts to the volunteers and do a quick just-in-time training to go over the specific instructions,” she said.

UTC students also are involved with the Hamilton County Health Department’s Twitter campaign #AlonetogetherCHA, which promotes social distancing.

A graduate of Chattanooga High School Center for Creative Arts, Pulliam’s studies at UTC focus on chronic disease prevention and control.

At press time, there were 121 positive coronavirus test results in Hamilton County, with 13 deaths.

HAMILTON COUNTY, TN – The Hamilton County Health Department is opening a new COVID-19 community testing site at the Riverfront Parkway Emissions Testing Center, 1620 Riverfront Parkway, Chattanooga TN, 37402. The new site is being operated in partnership with the Chattanooga Police Department, Opus Inspection Inc., Tennessee National Guard, and Tennessee Department of Health.

“Thanks to this new partnership with the Tennessee National Guard, we are expanding the capacity to do more community testing,” says Health Department Administrator Becky Barnes, “The goal has been and continues to be the identification of positive cases so that we can rigorously investigate them and their contacts to contain the spread of the virus.”

The Riverfront site will complement the existing Bonnyshire community testing site which has been in operation for the past two weeks. The new site will offer service on the weekends only, while the Bonnyshire site will continue to operate during the week. No physician referral or symptoms are necessary to make an appointment at either site.

Anyone wanting a COVID-19 test should call the Health Department scheduling number 209-8393 to make an appointment. 

The new site is predicted to handle hundreds of individuals per day on the weekends it is open. For now, the Riverfront site will be in operation for the next two weekends (April 25-26 and May 2-3). The decision to continue on subsequent weekends will be made at that time based on available resources. Like the Bonnyshire samples, all samples collected at the Riverfront site will be processed at the Hamilton County Laboratory at Baylor School.

Hamilton County Health Department COVID-19 Community Testing Sites.

Call 423-209-8393 for an appointment.

For more information about COVID-19, please call the Health Department COVID-19 Hotline at 423-209-8383, or visit the Health Department COVID-19 website.

By Jeremy Rossman, Honorary Senior Lecturer in Virology and President of Research-Aid Networks, University of Kent

For COVID-19, age and sex appear to be strong predictors of who lives and who dies.

The fatality rate for the disease is estimated to be 0.66%, according to data from China. In other words, 0.66% of people who are formally diagnosed with COVID-19, die. But the rate varies dramatically for different age groups, ranging from 0.0016% for children under ten to 7.8% in people over 79. Similar rates are seen in New York city. The graph below shows the increasing fatality rate for increasingly older populations.

Similar trends are seen with the percentage of COVID-19 patients that need hospitalization (ranging from 0% in under tens to 18.4% in over 79s). Yet those over 79 do not appear to be more likely to become infected, as they represent just 3.15% of the total confirmed cases.

Recent studies have shown that gender is a risk factor, too. Men are at a greater risk of dying from COVID-19 than women.

Data from China shows that men have 1.65 times the risk of dying from COVID-19 and in New York city, the rate is 1.77 times greater. Yet overall, men and women have roughly similar risks of getting the virus.

A declining immune system?

The ability of the human immune system to fight off pathogens declines over time and is significantly reduced in those over 70. Recent results show that in bad cases of COVID-19, there is a severe deficiency in certain classes of immune cells that fight off infections. These immune cells are known to be less active in the elderly, suggesting that an age-related decline in immune function may put the elderly at risk of more severe COVID-19 disease. Yet many of the most severe cases of COVID-19 are associated with over activation of the immune system.

The immune system is composed of many different parts and so it is possible to have suppression of one component and over-activation of another. But if the age-dependency of COVID-19 disease was specifically due to immune function, we would expect babies to also show severe disease, as their immune systems are still developing. This is what is seen in most seasonal flu epidemics, where those under two and those over 65 are at a greater risk of severe disease.

Changes in ACE2 levels?

In contrast to the flu, the 2003 Sars epidemic showed a fatality rate that increased with age similar to COVID-19 (4.26% for those under 44, rising to 64.2% for those over 74) and a 1.66 times greater fatality rate in men compared with women. The absence of severe infection in babies suggests that the age and gender disparity for COVID-19 may not be due to differences in immune response but rather something specific to the Sars viruses.

Both the 2003 SARS-CoV-1 and the current SARS-CoV-2 viruses bind to and use a protein known as ACE2 to gain entry into cells. ACE2 normally helps to regulate blood pressure and is found on the surface of many different cells, including those that line the lungs. The amount of ACE2 on human cells is higher in men and increases with age.

Certain variants of the ACE2 gene in humans are also associated with different levels of ACE2 expression, and the amount of ACE2 in different populations is somewhat correlated with COVID-19 disease. Also, hypertension (high blood pressure) is known to be a significant age-dependent risk factor for severe COVID-19 disease. Hypertension is typically treated with ACE-inhibitors that have also been shown to increase the amount of ACE2.

However, it appears that COVID-19 infection results in decreased ACE2 levels, which are associated with more severe lung disease. It is not clear what happens when ACE2 levels are high to begin with, such as in older men. Simply increasing ACE2 levels does not appear to cause more severe disease.

In addition, a recent clinical trial showed that ACE-inhibitor use was associated with less severe COVID-19 disease.

ACE2 is just one component of a complex regulatory system and so changes in ACE2 levels and action may have more complicated effects on disease progression than just virus entry into cells. These effects may change as the disease progresses and the immune system is activated.

Exposure to other coronaviruses?

Other related coronaviruses have been found to cause pneumonia in elderly patients and the likelihood of exposure to a virus increases with age. We also know that the human immune system can show some cross-reactivity between different coronaviruses.

Normally, recovery from an infection generates an immune memory that protects a person from being reinfected with the same pathogen. Cross-reactivity occurs when the immune system responds to a new pathogen as if it already had a memory of it. Sometimes this can protect against infection, but sometimes it can make the disease worse.

As severe COVID-19 disease appears to result from an over-activation of the immune system, it is possible that previous exposure to related coronaviruses may create an immune memory that primes the system to overreact to COVID-19. This process could be more prevalent in older people with more past exposure to other coronaviruses.

No data shows this cross-reactivity occurs in COVID-19 disease, but analysis of COVID-19 severe infection rates in areas with previous related coronavirus outbreaks could shed some light on the matter.

A simple explanation? It is also possible that the reason why more men and elderly people are dying from COVID-19 is more simple. We know that the risk of fatal COVID-19 disease is almost twice as great if the person has underlying health conditions. Most of these health conditions show increasing prevalence with age, such as hypertension, which increases in occurrence from 7.5% in those under 40 to over 63% in those over 60. This increasing rate of predisposing health conditions could directly increase the risk of severe COVID-19 disease.

We don’t know why these health conditions put people at risk of more severe disease. We also are just beginning to understand how COVID-19 causes disease in the first place. By understanding the process of severe COVID-19 disease we will be better placed to both mitigate the risks to specific populations and to develop interventions that block the most severe disease and possibly even prevent fatalities.