As international travel has opened up around the world, travelers find themselves facing more requirements than they did before. One of these requirements, often required by countries in order to enter them or by airlines in order to get on a flight, is a test for COVID-19 called a PCR test. People who want to travel should understand what a PCR test is so they can make sure they get the right test before they travel. This should ease their anxiety over entry requirements. It will also help ensure that they can make their trip as scheduled.
A PCR test is a certain kind of test used to detect the presence of the COVID-19 virus. The test looks for certain genetic material that is only present in COVID. To do this, a sample must be taken from the respiratory tract of the person being tested. This may be done in the form of a nasal swab or by obtaining saliva. In a PCR test, specialized laboratory conditions and equipment are used to amplify the amount of genetic material available. Specifically, lab technicians apply a special enzyme that turns viral RNA into DNA. The double helix of DNA is then unwound. The DNA is then copied, using a primer that only allows the replication of COVID DNA. This process is repeated 30-40 times, so there is significantly more genetic material from COVID that is available.
Finally, the genetic material is run through a specialized machine. This equipment tries to detect the viral DNA. If it does detect DNA from COVID-19, then the test is positive. If it does not detect DNA from COVID-19, then the test is negative. Because of the DNA amplification process, PCR tests are very accurate. They can detect even the smallest amount of viral genetic material. The amplification is key to the test’s accuracy. Other tests, without amplification, can only detect viral genetic material when it is above certain levels.
This means that the virus must replicate beyond a certain point in the human body before the test will work. PCR tests do have a few downsides. They must be handled and performed by skilled technicians. They also require expensive and specialized equipment and can take 12 hours - several days to complete. Finally, they are more expensive than other types of tests.
The PCR test is considered the gold standard of COVID-19 tests. This means that it is the most accurate way to determine whether a person has the virus. As such, it is helpful for travelers and for countries alike. When a PCR test is required for entry into a country, travelers can be as sure as possible that everyone entering the country does not have COVID. Similarly, governments can be as sure as possible that they are not allowing COVID into their country.
Note that there is no sure thing.
Because the PCR tests must be taken with plenty of time to get results before travel, there is a gap between when the test is taken and when travel occurs. Travelers can contract COVID-19 during that gap and still have a negative test. These travelers will bring COVID with them when they travel. However, the PCR test is the best option for limiting the spread of COVID. As technology develops and advances, there may be even better options in the future.
PCR test results are used at entry points to determine whether or not a particular traveler can enter a country. People with negative PCR tests are permitted to enter, as long as the rest of their paperwork is in order. People with positive PCR tests are not permitted to enter. They may also be required to isolate and quarantine, as required by the government of the country they are trying to enter.
Different countries may require PCR test results to be presented in different ways. Some will look for a certified electronic copy of test results that were submitted online. This may be an email or a QR code that they can scan when a person tries to enter. Others may require a hard copy of PCR test results. Travelers will need to get this hard copy from the place where they took their PCR test, or they may need to print it out on their own. If a country does not specify what form they want PCR test results in, travelers should have both available.
Note that a PCR test may not be all that travelers need in order to enter a particular country. They may also need a visa or other travel permission, some sort of health form, etc. It is up to every traveler to know what they need to have to enter a country. They will need to make sure that they have this paperwork ready before they travel.
It is likely that PCR tests will stick around for a while. They will either be used until COVID-19 is no longer a concern. This could happen if the spread slows dramatically, if most of the world is protected by the vaccine, or if a viable treatment for the condition means no one needs to worry anymore. The tests may also be phased out if a better testing solution arrives. If technology develops in a way that provides accurate testing on the spot, for instance, governments may simply test travelers as they arrive. However, it is likely that PCR tests will be used for travel for the foreseeable future.