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Why a single test is not good enough

The September 29th Garden Island describes two COVID cases that were picked up as positive on Kaua‘i. It describes how the cases were related to mainland travel but fortunately neither case was contagious during the time they were traveling to Kaua‘i. The article states they became contagious while they were in quarantine and therefore did not pose a risk to the other travelers. That is very good news but it is important to point out that as of October 15th this good news story could have turned into a very bad news story.

Those two people were in quarantine because that is the law at this time. After October 15th, they could have received a preflight COVID test. It would have been negative because they were apparently in the incubation phase and their COVID tests would still be negative. They would have then come off the flights and gone on with their everyday activities possibly exposing a lot of people because after October 15 if you have a negative preflight test you do not need to quarantine! Please note that with a proper two test system they most likely would have been picked up prior to going out into the community as they were with our current quarantine system.

The reason the single preflight test will miss so many people who are going to become contagious has become a political football with state government officials and others downplaying the risk of a single pretest. The reason that a single test could miss 30-40% of those who may become infectious is an important point for us to reach a scientific agreement on.

The science is this: the natural or common course of this illness consists of a 3-4 day incubation (or longer). The incubation period starts when the virus enters your body and begins using your cells as little factories producing more and more of the virus. For the first three days of incubation, no test we currently have can detect the virus because the numbers are so low. On day four the virus often explodes into greater numbers and estimates are that 33% percent of tests might be positive on day four, meaning 67% of those tested will still have a negative test. On days five to six, the viral load may be quite high and the person may start to have symptoms, but even by day eight, 20% of the tests could be negative. Even though people can remain very sick for a long time with this virus, by day 12-14 most people are much less contagious to others.

They may remain quite ill even as the virus is eliminated since the virus can damage so many organ systems. For many it is like a hurricane went through leaving a wake of destruction.

To review…. there are about 12-14 days from the day one catches the virus until they are much less contagious. For the first four of those days you will most likely have a negative test even though the virus is in your body and your test could even still be negative on day eight. That means that if you test hundreds of people with a single pretest, one third or more of those people may have the virus and the test will not show it. In addition, anybody could catch the virus after their test, in the airport, or during the long flight.

Many places show that high percentages of people who are tested have the virus but what we really don’t know is what percentage of those who want to travel will have the virus. We do know that many nations around the world are not letting travelers in from the United States because our disease is so widespread. If we estimate that one percent of those traveling may have the virus, we could be letting in 32 infected people for every 10,000 arrivals. If we had 1000 visitors a day that would be 100 people a month bringing infections into our community.

The safest way to contain the virus is a well-monitored 14 day quarantine. If we want to shorten the quarantine, we could consider requiring a negative pretest and at least a negative second test after 6-7 days in quarantine. It is not as safe as 14 days in quarantine but much safer than a single pretest with no quarantine. As was pointed out in another article in the Garden Island on Sept. 29, thanks to our mayor, district health officer and our community efforts we have been one of the most COVID- free counties in the world. As I understand it, Mayor Kawakami and Dr Berreman are also in support of a two test system.

There are a growing number of people who can work remotely, want to come to a safe place, and will be happy that we are remaining so strict. My hope and suggestion is that we stay strict, go to no less than a 7 day quarantine and require at least two tests. I think we should also give a lot of consideration to the advantages of attracting visitors who want to stay a while and want to be as safe as we have been. Consider writing to the Governor and Lt Governor; a single pretest and no quarantine is simply too dangerous.

This column represents a sharing of information. No content on this column should ever be used as a substitute for direct medical advice from your doctor or other qualified clinicians.


Lee A Evslin, MD is a Board Certified Pediatrician and Fellow of The American Academy of Pediatrics. He was a former healthcare administrator on Kaua‘i and periodically writes a column for The Garden Island.
Source: The Garden Island

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