COVID-19

Letter to the Community: September 10, 2020

Posted

Hello Thurston County! I hope you had a great Labor Day weekend. I enjoyed the beautiful sunshine and warm weather.

I look forward to reading the questions that come in each week from residents. From the questions that were sent in, I have selected three to answer.

Question 1: What are false positive results for COVID-19 tests and what is their significance?

In a perfect world, every positive COVID-19 test result would mean a person has COVID-19 and a negative test result would mean they do not have the disease. However, every test can sometimes give a false positive, meaning the test shows someone has a condition when they really don’t. A false negative means the test does not show a person has a disease when they do.

Tests that are approved by the Food and Drug Administration for Emergency Use Authorization for SARS-CoV-2 detection have specific standards that must be meet in order to be approved. The risk of a false positive is that someone who does not have COVID-19 would isolate for 10 days and their close contacts would be tested for the disease.

Science has proven, someone who has had COVID-19 may continue to test positive even after they have recovered from the disease and finished their isolation period. In this situation, it would not be considered a false positive because the person had a known infection and likely there are pieces of viral genetic material and proteins picked up by the test. The CDC has studied whether these individuals are releasing infectious particles and they found in most cases these positive test results do not reflect the shedding of infectious particles after the isolation period has ended.

There is far greater risk to the community when someone actually has the disease, but the test result come back negative; this is called a false negative. With our current testing, false negatives are far more common than false positives and often occur when people are tested too soon after they have been infected and have not started shedding viral particles. A false negative result occurs if no infectious particles were contained in the sample due to how it was taken or if the viral material is too small for the test to detect it. Thurston County disease investigators instruct someone who has symptoms of COVID-19 and has had a known exposure to the virus to isolate for at least 10 days and remain fever free for 24 hours without medication.

The COVID-19 tests are effective but not perfect. We use testing, contact tracing, isolation and quarantine, and preventative measures to help minimize the effect of false positive and false negative test results.

Question 2: My son will be coming home from college for the holidays in several months. His dad is a very high-risk individual for contracting COVID-19. Does my son need to get tested when he comes home? Should his dad isolate? What do you recommend for our situation?

Great question! Since COVID-19 has an incubation period of 14 days, the safest course of action would be for your son to quarantine away from his father for 14 days upon return from school. The CDC recommendation for high-risk individuals is to avoid contact with people who may have been exposed to COVID-19 within the preceding 14 days. This is why people being admitted to high-risk settings, like

long-term care facilities, are quarantined for 14 days before being allowed to join the population even if they have had a COVID-19 test and it is negative. At this time, there is no current public health recommendation to test people who have not been identified as close contacts and who do not have symptoms of COVID-19.

Question 3: Do students from other places (counties, states, countries) who are living on a college campus within Thurston County actually count as county residents with regard to their positive or negative test results?

Very good question! At this time, only students who list their permanent residence as an address in Thurston County are counted towards our county COVID-19 case counts. We keep track of which cases are in colleges as well as their institution name. By tracking the number of cases contracted outside of our county, we can more accurately monitor our in-county transmission rates.

The case investigation of Thurston County residents who test positive for COVID-19, including those away at college, is performed by Thurston County Public Health and Social Services. So, if a college student receives a call from a case investigator from their county of residence, it is important to answer and share the requested information.

Thank you for the excellent questions! Please submit your questions for next week to tcphss.pio@co.thurston.wa.us. Have a great week everyone!

Wishing you the best of health,

Dimyana Abdelmalek, MD, MPH

Health Officer, Thurston County

Comments

No comments on this story | Please log in to comment by clicking here
Please log in or register to add your comment