By Claudia Finkelstein, Michigan State University
With the holidays ahead, many people consider visiting relatives or friends in the coming weeks. At the same time, cases of COVID-19 are rising to their highest level since the beginning of the pandemic. As a doctor, daughter of vulnerable seniors, and mother of young adults, I have thought a lot about whether tests will help me decide whether it is safe to see my family.
Tests can help you make sure you and your loved ones stay healthy, but COVID-19 testing isn’t as simple as yes or no, infected or safe. There are many factors to consider when using a coronavirus test to safely plan your vacation trips.
Some tests are better than others
There are basically two categories of tests.
Antibody tests that look for evidence of a previous infection cannot tell you if you currently have COVID-19 and are not helpful in planning a family visit.
The other category of tests looks for clues about the virus in your body. There are two types of these virus tests – RT-PCR tests and rapid antigen tests – and these are used to prevent the coronavirus from spreading.
No laboratory test for COVID-19 is 100% accurate. While false positives are certainly not a good thing, a false negative result – testing negative when you actually have the virus – is the greater danger if you are planning on seeing a family. The false negative rates for RT-PCR tests are between 2% and 29%. Much of this area is due to different manufacturers and user errors. While these tests are pretty accurate, they often involve a visit to a health care provider and are slightly expensive – around $ 100, although the cost varies widely by state – and can take up to three days to get results. RT-PCR tests are the best tests available, but for some people, especially if you’re seeing someone in an at-risk age group, the 29% false negative rate in the upper range can leave more uncertainty than you’d like.
In comparison, rapid antigen tests are faster and cheaper, but less accurate than RT-PCR tests. You will usually get results within a day of taking the test, but false negative rates can be up to 50%. They are most likely to be accurate when given to people with symptoms within a week of the onset of symptoms. However, rapid tests are not diagnostic tests for a person. They’re much better at monitoring whole populations where people can be tested repeatedly, and frankly, make little sense as a one-time test.
A quick test may give you immediate results at a lower cost, but it shouldn’t be the only thing you use to make a travel decision. When a family member’s health is at stake, accuracy is your friend. RT-PCR tests are generally considered more accurate.
Timing is important
Regardless of which virus test you use, the results are only accurate for the moment you were tested and only reflect the test’s ability to detect the virus. Of course, a negative result today does not prevent you from getting infected tomorrow.
But with the coronavirus, a negative test doesn’t mean you haven’t been exposed to the virus either. The time between contact with the virus and the start of the release of infectious virus particles – the incubation period – varies between two and 14 days. For example, it is possible that you will be exposed today, test negative tomorrow, and become contagious a few days later.
In addition, it is possible to spread the virus before you show symptoms – if you are presymptomatic – or if you don’t develop symptoms at all.
Minimize risk, accept uncertainty
If you have any symptoms at all, stay home first. If you don’t have symptoms, you can start thinking about traveling for the holidays.
Knowing that tests are not perfect, it is safest to perform a strict self-quarantine 14 days before your visit. Testing can be a helpful data point, but quarantine is the more foolproof option.
If you can’t quarantine for 14 days, your best bet is to limit your potential exposure to the virus, isolate for as long as possible before you travel and get tested.
If you are concerned about being an asymptomatic carrier and cannot isolate, you should get a test at least five days after your last possible exposure. This will maximize the chance that a test will detect the virus if you are infected.
Remember that traveling itself also carries the risk of exposure. Driving with reasonable precautions – wearing a mask, washing hands, and social distancing – appears to be safer than flying.
The flight process – the crowded airports, bus rides, and cramped seats on the plane – is a serious exposure risk. Ideally, isolate yourself at your destination for as long as possible after the flight and have yourself tested. That’s a lot of alone time and waiting for test results, but I can’t think of any greater effort than the safety of loved ones.
You are not alone in this
Maintaining health is a group work and it only takes one infected person to cause an outbreak. Openly discuss the precautions that the people you visit take and the possibilities of social distancing during the visit.
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Remember that a negative test in a group of travelers is just that negative test. Just because you test negative doesn’t mean you can assume that other people in your household are negative too. Everyone must be tested and follow the same isolation measures as much of the spread occurs at smaller private gatherings in a confined space.
Many people want to see our loved ones on vacation. However, there are tremendous life and death reasons to carefully plan your visit and use information, isolation, and testing wisely. You can decide the risk is too high and that’s fine. However, if you do choose to go on vacation, a strict 14-day quarantine is the safest option. Tests can help you make a decision, but they’re not the only thing to rely on.
Claudia Finkelstein, Associate Professor of Family Medicine, Michigan State University
This article is republished by The Conversation under a Creative Commons license. Read the original article.