Examples of clear/accurate and unclear/potentially misleading website content
| Information item | Example of unclear/potentially misleading information | Example of clearer and more accurate communication |
| Who should take the test? |
“you can do the swab test between 1–5 days post exposure."
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This is likely to be too early for the PCR molecular virus test specified to be sufficiently sensitive. Median time between exposure and symptom onset is around 5 days,54 so this proposed timing is likely pre-symptomatic when sensitivity is lower. |
“Ideally samples should be taken from symptomatic individuals between days 1–5 from symptom onset. However, there are many cases when virus can be detected later into the illness."
20
It would also be helpful to communicate that taking the test too early or late when it is less accurate may result in the test missing COVID-19 when it is present. |
| Test accuracy |
“This test offers 99.9% reliability"
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“What is the accuracy of the test? 99.9%" 29 It is unclear what the terms ‘accuracy’ or ‘reliability’ mean. | No website provided a full explanation of accuracy, we suggest our own example as follows (data provided for example and text can be amended to clearly indicate molecular or antibody tests) “Test accuracy: The tests are sometimes inaccurate. If you have a negative result (indicating you have not got COVID-19) then the test is very likely to be correct. If you get a positive result (indicating you have got COVID-19) then the result is less accurate. Of the people who test positive, 92 in 100 do actually have COVID-19. Of the people who test negative, more than 99 in 100 do not have COVID-19. Here is more detail on the science: Test accuracy was measured in an independent evaluation of 158 people with COVID-19 and 364 people without COVID-19 (give reference for the underlying evidence). The test had a sensitivity of 98% and a specificity of 99.2%. That means that if 1000 people are tested, and 100 of those have COVID-19, then 98 of the 100 people with COVID-19 will be detected and two will be missed (test negative). Of the 900 people who do not have COVID-19, 892 will test negative, and eight will test positive (and believe they have COVID-19 when they do not).“ |
| Interpreting test results of molecular virus tests |
“This highly accurate test will give you peace of mind that you can't infect others. This test is relevant when people who have been isolating wish to return to their household, community or workplace and need to know that they aren't infectious”
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This refers to the PCR molecular virus test, which is known to have low sensitivity so people testing negative may still be infected and infectious to others. Reasons for taking the PCR test cited as “You need to know if you are infectious or not” and “You want to let your household members know if they need to self-isolate” 25 |
“If you have tested positive for COVID-19, self-isolation is recommended so that you do not pass the virus to others…If your results are negative and you’re having symptoms, continue to follow isolation precautions and ask your healthcare provider if you need further testing.”
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Linking information on the low negative predictive value of the PCR test to recommendations to continue self-isolation may strengthen the message. |
| Interpreting test results of antibody tests |
"A positive test result indicates that you have been exposed to COVID-19 and your immune system has produced antibodies in response to the virus. If you have had no symptoms for at least 7 days, you should have some level of immunity to COVID-19 and may not be able to transmit the virus to others or become infected by it again."
19
We do not currently know whether the presence of antibodies infers immunity. | “There is still a great deal about COVID-19 immunity that we do not yet fully understand… If your IgG test is positive it means you have had COVID-19 exposure sufficiently to make an antibody response to the virus. There is currently no scientific evidence confirming if the presence of antibodies correlates to immunity or how long the antibodies will last for.” 21 |