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Community spread and a sharp rise in case numbers
July 12, 2020

M

ac Ernest is a retired physician. Before moving to Oriental in 2014,

Mac Ernest

Mac was the Chair of the Dept of Obstetrics and Gynecology at Carolinas Healthcare in Charlotte. Prior to that he was Professor of Obstetrics-Gynecology at Wake Forest medical school in Winston-Salem.

In addition to patient care and teaching, his research has included studying infectious diseases.

Mac has been providing a series of columns about COVID-19. This column was prepared with the assistance of Sharon Stephenson MD, Ros Cheetham MSc and Diana Silimperi MD.

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On Sunday, March 29, Pamlico County had our first reported case of COVID-19. Six days later, we had our second. During the entire month of April, we only had 5 cases, and only 4 cases in May, all now recovered. As we moved into June, we saw a rapid increase in cases and one death, and now in July we see new cases almost daily. What is going on?

Reported cases of COVID-19 by month, as of July 12, 2020.

(Source: https://covid19.ncdhhs.gov/dashboard/cases Note that the totals shown on the state dashboard may differ slightly from data issued by the County because of timing.)

Cases in April and May

Early cases in our county were from individuals who were clearly exposed to an infected person by travelling outside the county (sometimes to a known “hotspot”) or by contact with a visitor coming from another state or county. In these situations, an individual entered Pamlico County already harboring the virus from exposure outside the county, became ill, was tested and found to have COVID-19.

Many times in these situations, the individual can determine when and where the exposure occurred, and can identify people whom he or she contacted in the period before and after symptoms appeared. The Health Department can then identify those contacts, quarantine them until certain that they are not infected, and thereby reduce further exposure or transmission to others in the county. The growth in the number of cases in this situation can be relatively slow and that is what we saw in April and May.

June and July: Community Spread

Now, many of the newest cases have no history of any obvious exposure to an infected person, nor have those infected visited some other place with a high rate of cases. In other words, we simply don’t know how they contracted the infection. Infectious disease experts refer to this as “community spread”.

When there is community spread, the virus is present in a significant number of individuals in a location – in our case, Pamlico County. Many of these individuals may be asymptomatic or presymptomatic, exposing many people to the virus even though they don’t leave the county.

One person with coronavirus can infect 2-3 other people. Each of those can infect another 2-3 people. And so on.

Experts estimate that, on average, every person infected with coronavirus will infect another 2-3 individuals. Frequently, the person spreading the infection feels well and has no idea that they are contagious. Generally, those who do get infected during community spread do not know the source of their infection.

Why did the case count increase so quickly?

Community spread is much more rapid because a larger number of people are spreading the virus without being aware of it. Though the Health Department still can do contact tracing once a person tests positive, they may be missing others who are infected and spreading the virus unknowingly.

Because of this, community spread does not depend on direct contact with a known infected person or traveling to another county which has a higher rate of COVID or documented community spread. When community spread is occurring, everyone outside one’s immediate family and shared living circle MUST be considered as potentially infected.

What can we do to slow community spread?

The rate of community spread depends on the degree to which individuals protect themselves and others by social distancing and wearing masks, and by careful handwashing (the 3 Ws). Even when community spread is occurring, it can be slowed by physical distancing and widespread practice of wearing a face covering when in public.

On the other hand, community spread can rapidly accelerate when large gatherings and close contact without masks or physical distancing occurs. Large gatherings of family members who do not live together (especially when those family members come to visit in Pamlico County from elsewhere) are important sources of community spread here and in other locations.

We in Pamlico County need to realize that the chance of a COVID-19 infection today is much more likely than one month ago, and will continue to grow until one or more of the following occur:

• An effective vaccine for the coronavirus is developed and delivered to a large portion of the population: Vaccine development is challenging, and no date has been set for large scale vaccination against the novel coronavirus.
• “Herd immunity” is adequate: Herd immunity occurs when a sizable portion of a population develops some form of immunity to a disease. We do not yet know how long antibodies will be effective with this disease; it varies from infection to infection and may need to be as high as 70% for the coronavirus causing COVID-19 infections. Currently, it appears that about 10-12% of folks in North Carolina have antibodies to the virus.
• An effective treatment for the virus is available: While a number of drugs are currently under investigation, we do not have a reliable means to treat this specific organism and must rely on treating complications of the disease.

The only option available RIGHT NOW:

Extreme care in reducing community spread becomes the norm: Avoiding large gatherings, wearing a face covering when around others, physical distancing, and compulsive handwashing are some of the critical practices that must occur on a large scale to reduce spread in our community.

During this period of community spread of COVID-19, we in Pamlico County have an opportunity to change the course of this disease and slow its progress by changing our behavior: wearing a face covering, practicing physical distancing and careful handwashing, and avoiding large groups (25 people outside, 10 inside).

We can work together to prevent our friends and family members from becoming ill, or we can stand by and watch those about whom we care suffer the consequences of our inaction.

How we proceed is entirely up to us.

More details from the NCDHHS COVID-19 Dashboard: (from July 12, 2020)

Further breakdown of infection rates among Pamlico County residents as of July 12, 2020.